diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ffe8340
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,9 @@
+*.bin
+*.hex
+*.d
+*.elf
+*.map
+*.o
+*.elf
+src/version.h
+src/mapfile
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..6bccd68
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "libopencm3"]
+ path = libopencm3
+ url = https://github.com/libopencm3/libopencm3
diff --git a/COPYING b/COPYING
new file mode 100644
index 0000000..4432540
--- /dev/null
+++ b/COPYING
@@ -0,0 +1,676 @@
+
+ GNU GENERAL PUBLIC LICENSE
+ Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc.
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+ The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works. By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users. We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors. You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+ To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights. Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+ For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received. You must make sure that they, too, receive
+or can get the source code. And you must show them these terms so they
+know their rights.
+
+ Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+ For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software. For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+ Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so. This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software. The systematic
+pattern of such abuse occurs in the area of products for individuals to
+use, which is precisely where it is most unacceptable. Therefore, we
+have designed this version of the GPL to prohibit the practice for those
+products. If such problems arise substantially in other domains, we
+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+ Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary. To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
+
+ The precise terms and conditions for copying, distribution and
+modification follow.
+
+ TERMS AND CONDITIONS
+
+ 0. Definitions.
+
+ "This License" refers to version 3 of the GNU General Public License.
+
+ "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+ "The Program" refers to any copyrightable work licensed under this
+License. Each licensee is addressed as "you". "Licensees" and
+"recipients" may be individuals or organizations.
+
+ To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy. The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+ A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+ To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy. Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+ To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies. Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+ An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License. If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+ 1. Source Code.
+
+ The "source code" for a work means the preferred form of the work
+for making modifications to it. "Object code" means any non-source
+form of a work.
+
+ A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+ The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form. A
+"Major Component", in this context, means a major essential component
+(kernel, window system, and so on) of the specific operating system
+(if any) on which the executable work runs, or a compiler used to
+produce the work, or an object code interpreter used to run it.
+
+ The "Corresponding Source" for a work in object code form means all
+the source code needed to generate, install, and (for an executable
+work) run the object code and to modify the work, including scripts to
+control those activities. However, it does not include the work's
+System Libraries, or general-purpose tools or generally available free
+programs which are used unmodified in performing those activities but
+which are not part of the work. For example, Corresponding Source
+includes interface definition files associated with source files for
+the work, and the source code for shared libraries and dynamically
+linked subprograms that the work is specifically designed to require,
+such as by intimate data communication or control flow between those
+subprograms and other parts of the work.
+
+ The Corresponding Source need not include anything that users
+can regenerate automatically from other parts of the Corresponding
+Source.
+
+ The Corresponding Source for a work in source code form is that
+same work.
+
+ 2. Basic Permissions.
+
+ All rights granted under this License are granted for the term of
+copyright on the Program, and are irrevocable provided the stated
+conditions are met. This License explicitly affirms your unlimited
+permission to run the unmodified Program. The output from running a
+covered work is covered by this License only if the output, given its
+content, constitutes a covered work. This License acknowledges your
+rights of fair use or other equivalent, as provided by copyright law.
+
+ You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force. You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
+with facilities for running those works, provided that you comply with
+the terms of this License in conveying all material for which you do
+not control copyright. Those thus making or running the covered works
+for you must do so exclusively on your behalf, under your direction
+and control, on terms that prohibit them from making any copies of
+your copyrighted material outside their relationship with you.
+
+ Conveying under any other circumstances is permitted solely under
+the conditions stated below. Sublicensing is not allowed; section 10
+makes it unnecessary.
+
+ 3. Protecting Users' Legal Rights From Anti-Circumvention Law.
+
+ No covered work shall be deemed part of an effective technological
+measure under any applicable law fulfilling obligations under article
+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+ When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
+is effected by exercising rights under this License with respect to
+the covered work, and you disclaim any intention to limit operation or
+modification of the work as a means of enforcing, against the work's
+users, your or third parties' legal rights to forbid circumvention of
+technological measures.
+
+ 4. Conveying Verbatim Copies.
+
+ You may convey verbatim copies of the Program's source code as you
+receive it, in any medium, provided that you conspicuously and
+appropriately publish on each copy an appropriate copyright notice;
+keep intact all notices stating that this License and any
+non-permissive terms added in accord with section 7 apply to the code;
+keep intact all notices of the absence of any warranty; and give all
+recipients a copy of this License along with the Program.
+
+ You may charge any price or no price for each copy that you convey,
+and you may offer support or warranty protection for a fee.
+
+ 5. Conveying Modified Source Versions.
+
+ You may convey a work based on the Program, or the modifications to
+produce it from the Program, in the form of source code under the
+terms of section 4, provided that you also meet all of these conditions:
+
+ a) The work must carry prominent notices stating that you modified
+ it, and giving a relevant date.
+
+ b) The work must carry prominent notices stating that it is
+ released under this License and any conditions added under section
+ 7. This requirement modifies the requirement in section 4 to
+ "keep intact all notices".
+
+ c) You must license the entire work, as a whole, under this
+ License to anyone who comes into possession of a copy. This
+ License will therefore apply, along with any applicable section 7
+ additional terms, to the whole of the work, and all its parts,
+ regardless of how they are packaged. This License gives no
+ permission to license the work in any other way, but it does not
+ invalidate such permission if you have separately received it.
+
+ d) If the work has interactive user interfaces, each must display
+ Appropriate Legal Notices; however, if the Program has interactive
+ interfaces that do not display Appropriate Legal Notices, your
+ work need not make them do so.
+
+ A compilation of a covered work with other separate and independent
+works, which are not by their nature extensions of the covered work,
+and which are not combined with it such as to form a larger program,
+in or on a volume of a storage or distribution medium, is called an
+"aggregate" if the compilation and its resulting copyright are not
+used to limit the access or legal rights of the compilation's users
+beyond what the individual works permit. Inclusion of a covered work
+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
+
+ 6. Conveying Non-Source Forms.
+
+ You may convey a covered work in object code form under the terms
+of sections 4 and 5, provided that you also convey the
+machine-readable Corresponding Source under the terms of this License,
+in one of these ways:
+
+ a) Convey the object code in, or embodied in, a physical product
+ (including a physical distribution medium), accompanied by the
+ Corresponding Source fixed on a durable physical medium
+ customarily used for software interchange.
+
+ b) Convey the object code in, or embodied in, a physical product
+ (including a physical distribution medium), accompanied by a
+ written offer, valid for at least three years and valid for as
+ long as you offer spare parts or customer support for that product
+ model, to give anyone who possesses the object code either (1) a
+ copy of the Corresponding Source for all the software in the
+ product that is covered by this License, on a durable physical
+ medium customarily used for software interchange, for a price no
+ more than your reasonable cost of physically performing this
+ conveying of source, or (2) access to copy the
+ Corresponding Source from a network server at no charge.
+
+ c) Convey individual copies of the object code with a copy of the
+ written offer to provide the Corresponding Source. This
+ alternative is allowed only occasionally and noncommercially, and
+ only if you received the object code with such an offer, in accord
+ with subsection 6b.
+
+ d) Convey the object code by offering access from a designated
+ place (gratis or for a charge), and offer equivalent access to the
+ Corresponding Source in the same way through the same place at no
+ further charge. You need not require recipients to copy the
+ Corresponding Source along with the object code. If the place to
+ copy the object code is a network server, the Corresponding Source
+ may be on a different server (operated by you or a third party)
+ that supports equivalent copying facilities, provided you maintain
+ clear directions next to the object code saying where to find the
+ Corresponding Source. Regardless of what server hosts the
+ Corresponding Source, you remain obligated to ensure that it is
+ available for as long as needed to satisfy these requirements.
+
+ e) Convey the object code using peer-to-peer transmission, provided
+ you inform other peers where the object code and Corresponding
+ Source of the work are being offered to the general public at no
+ charge under subsection 6d.
+
+ A separable portion of the object code, whose source code is excluded
+from the Corresponding Source as a System Library, need not be
+included in conveying the object code work.
+
+ A "User Product" is either (1) a "consumer product", which means any
+tangible personal property which is normally used for personal, family,
+or household purposes, or (2) anything designed or sold for incorporation
+into a dwelling. In determining whether a product is a consumer product,
+doubtful cases shall be resolved in favor of coverage. For a particular
+product received by a particular user, "normally used" refers to a
+typical or common use of that class of product, regardless of the status
+of the particular user or of the way in which the particular user
+actually uses, or expects or is expected to use, the product. A product
+is a consumer product regardless of whether the product has substantial
+commercial, industrial or non-consumer uses, unless such uses represent
+the only significant mode of use of the product.
+
+ "Installation Information" for a User Product means any methods,
+procedures, authorization keys, or other information required to install
+and execute modified versions of a covered work in that User Product from
+a modified version of its Corresponding Source. The information must
+suffice to ensure that the continued functioning of the modified object
+code is in no case prevented or interfered with solely because
+modification has been made.
+
+ If you convey an object code work under this section in, or with, or
+specifically for use in, a User Product, and the conveying occurs as
+part of a transaction in which the right of possession and use of the
+User Product is transferred to the recipient in perpetuity or for a
+fixed term (regardless of how the transaction is characterized), the
+Corresponding Source conveyed under this section must be accompanied
+by the Installation Information. But this requirement does not apply
+if neither you nor any third party retains the ability to install
+modified object code on the User Product (for example, the work has
+been installed in ROM).
+
+ The requirement to provide Installation Information does not include a
+requirement to continue to provide support service, warranty, or updates
+for a work that has been modified or installed by the recipient, or for
+the User Product in which it has been modified or installed. Access to a
+network may be denied when the modification itself materially and
+adversely affects the operation of the network or violates the rules and
+protocols for communication across the network.
+
+ Corresponding Source conveyed, and Installation Information provided,
+in accord with this section must be in a format that is publicly
+documented (and with an implementation available to the public in
+source code form), and must require no special password or key for
+unpacking, reading or copying.
+
+ 7. Additional Terms.
+
+ "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law. If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+ When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
+it. (Additional permissions may be written to require their own
+removal in certain cases when you modify the work.) You may place
+additional permissions on material, added by you to a covered work,
+for which you have or can give appropriate copyright permission.
+
+ Notwithstanding any other provision of this License, for material you
+add to a covered work, you may (if authorized by the copyright holders of
+that material) supplement the terms of this License with terms:
+
+ a) Disclaiming warranty or limiting liability differently from the
+ terms of sections 15 and 16 of this License; or
+
+ b) Requiring preservation of specified reasonable legal notices or
+ author attributions in that material or in the Appropriate Legal
+ Notices displayed by works containing it; or
+
+ c) Prohibiting misrepresentation of the origin of that material, or
+ requiring that modified versions of such material be marked in
+ reasonable ways as different from the original version; or
+
+ d) Limiting the use for publicity purposes of names of licensors or
+ authors of the material; or
+
+ e) Declining to grant rights under trademark law for use of some
+ trade names, trademarks, or service marks; or
+
+ f) Requiring indemnification of licensors and authors of that
+ material by anyone who conveys the material (or modified versions of
+ it) with contractual assumptions of liability to the recipient, for
+ any liability that these contractual assumptions directly impose on
+ those licensors and authors.
+
+ All other non-permissive additional terms are considered "further
+restrictions" within the meaning of section 10. If the Program as you
+received it, or any part of it, contains a notice stating that it is
+governed by this License along with a term that is a further
+restriction, you may remove that term. If a license document contains
+a further restriction but permits relicensing or conveying under this
+License, you may add to a covered work material governed by the terms
+of that license document, provided that the further restriction does
+not survive such relicensing or conveying.
+
+ If you add terms to a covered work in accord with this section, you
+must place, in the relevant source files, a statement of the
+additional terms that apply to those files, or a notice indicating
+where to find the applicable terms.
+
+ Additional terms, permissive or non-permissive, may be stated in the
+form of a separately written license, or stated as exceptions;
+the above requirements apply either way.
+
+ 8. Termination.
+
+ You may not propagate or modify a covered work except as expressly
+provided under this License. Any attempt otherwise to propagate or
+modify it is void, and will automatically terminate your rights under
+this License (including any patent licenses granted under the third
+paragraph of section 11).
+
+ However, if you cease all violation of this License, then your
+license from a particular copyright holder is reinstated (a)
+provisionally, unless and until the copyright holder explicitly and
+finally terminates your license, and (b) permanently, if the copyright
+holder fails to notify you of the violation by some reasonable means
+prior to 60 days after the cessation.
+
+ Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+ Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License. If your rights have been terminated and not permanently
+reinstated, you do not qualify to receive new licenses for the same
+material under section 10.
+
+ 9. Acceptance Not Required for Having Copies.
+
+ You are not required to accept this License in order to receive or
+run a copy of the Program. Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance. However,
+nothing other than this License grants you permission to propagate or
+modify any covered work. These actions infringe copyright if you do
+not accept this License. Therefore, by modifying or propagating a
+covered work, you indicate your acceptance of this License to do so.
+
+ 10. Automatic Licensing of Downstream Recipients.
+
+ Each time you convey a covered work, the recipient automatically
+receives a license from the original licensors, to run, modify and
+propagate that work, subject to this License. You are not responsible
+for enforcing compliance by third parties with this License.
+
+ An "entity transaction" is a transaction transferring control of an
+organization, or substantially all assets of one, or subdividing an
+organization, or merging organizations. If propagation of a covered
+work results from an entity transaction, each party to that
+transaction who receives a copy of the work also receives whatever
+licenses to the work the party's predecessor in interest had or could
+give under the previous paragraph, plus a right to possession of the
+Corresponding Source of the work from the predecessor in interest, if
+the predecessor has it or can get it with reasonable efforts.
+
+ You may not impose any further restrictions on the exercise of the
+rights granted or affirmed under this License. For example, you may
+not impose a license fee, royalty, or other charge for exercise of
+rights granted under this License, and you may not initiate litigation
+(including a cross-claim or counterclaim in a lawsuit) alleging that
+any patent claim is infringed by making, using, selling, offering for
+sale, or importing the Program or any portion of it.
+
+ 11. Patents.
+
+ A "contributor" is a copyright holder who authorizes use under this
+License of the Program or a work on which the Program is based. The
+work thus licensed is called the contributor's "contributor version".
+
+ A contributor's "essential patent claims" are all patent claims
+owned or controlled by the contributor, whether already acquired or
+hereafter acquired, that would be infringed by some manner, permitted
+by this License, of making, using, or selling its contributor version,
+but do not include claims that would be infringed only as a
+consequence of further modification of the contributor version. For
+purposes of this definition, "control" includes the right to grant
+patent sublicenses in a manner consistent with the requirements of
+this License.
+
+ Each contributor grants you a non-exclusive, worldwide, royalty-free
+patent license under the contributor's essential patent claims, to
+make, use, sell, offer for sale, import and otherwise run, modify and
+propagate the contents of its contributor version.
+
+ In the following three paragraphs, a "patent license" is any express
+agreement or commitment, however denominated, not to enforce a patent
+(such as an express permission to practice a patent or covenant not to
+sue for patent infringement). To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+ If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients. "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+ If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+ A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License. You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+ Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+ 12. No Surrender of Others' Freedom.
+
+ If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License. If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all. For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+ 13. Use with the GNU Affero General Public License.
+
+ Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work. The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+ 14. Revised Versions of this License.
+
+ The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time. Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+ Each version is given a distinguishing version number. If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation. If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+ If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+ Later license versions may give you additional or different
+permissions. However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+ 15. Disclaimer of Warranty.
+
+ THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+ 16. Limitation of Liability.
+
+ IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+
+ Copyright (C)
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see .
+
+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ Copyright (C)
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+.
+
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..358c687
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,18 @@
+ifneq ($(V), 1)
+MFLAGS += --no-print-dir
+Q := @
+endif
+
+all:
+ $(Q)if [ ! -f libopencm3/Makefile ]; then \
+ echo "Initialising git submodules..." ;\
+ git submodule init ;\
+ git submodule update ;\
+ fi
+ $(Q)$(MAKE) $(MFLAGS) -C libopencm3 lib
+ $(Q)$(MAKE) $(MFLAGS) -C src
+
+clean:
+ $(Q)$(MAKE) $(MFLAGS) -C libopencm3 $@
+ $(Q)$(MAKE) $(MFLAGS) -C src $@
+
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..c80376b
--- /dev/null
+++ b/README.md
@@ -0,0 +1,2 @@
+# pill\_6502
+
diff --git a/circle.yml b/circle.yml
new file mode 100644
index 0000000..b446182
--- /dev/null
+++ b/circle.yml
@@ -0,0 +1,10 @@
+version: 1
+test:
+ override:
+ - PATH=/home/ubuntu/pill_6502/gcc-arm-none-eabi-7-2017-q4-major/bin/:${PATH} make
+ - cp src/pill_6502.bin $CIRCLE_ARTIFACTS/
+ - cp src/pill_6502.elf $CIRCLE_ARTIFACTS/
+dependencies:
+ pre:
+ - wget -O armgcc.tar.bz2 'https://developer.arm.com/-/media/Files/downloads/gnu-rm/7-2017q4/gcc-arm-none-eabi-7-2017-q4-major-linux.tar.bz2?revision=375265d4-e9b5-41c8-bf23-56cbe927e156?product=GNU%20Arm%20Embedded%20Toolchain,64-bit,,Linux,7-2017-q4-major'
+ - tar -xvjf armgcc.tar.bz2
diff --git a/libopencm3 b/libopencm3
new file mode 160000
index 0000000..3922cc7
--- /dev/null
+++ b/libopencm3
@@ -0,0 +1 @@
+Subproject commit 3922cc7d3ea362b816cc1de6d3287375afbe58aa
diff --git a/src/Makefile b/src/Makefile
new file mode 100644
index 0000000..77707ce
--- /dev/null
+++ b/src/Makefile
@@ -0,0 +1,68 @@
+ifneq ($(V), 1)
+MAKEFLAGS += --no-print-dir
+Q := @
+endif
+
+OPT_FLAGS ?= -O2
+
+CFLAGS += -Wall -Wextra -Werror -Wno-char-subscripts\
+ $(OPT_FLAGS) -std=gnu99 -g3 -MD \
+ -I.
+LDFLAGS += $(OPT_FLAGS)
+
+SRC = \
+ cdcacm.c \
+ main.c \
+
+CROSS_COMPILE ?= arm-none-eabi-
+CC = $(CROSS_COMPILE)gcc
+OBJCOPY = $(CROSS_COMPILE)objcopy
+
+OPT_FLAGS = -Os
+CFLAGS += -mcpu=cortex-m3 -mthumb \
+ -DSTM32F1 -DDISCOVERY_STLINK -I../libopencm3/include \
+ -I .
+LDFLAGS_BOOT := $(LDFLAGS) --specs=nano.specs \
+ -lopencm3_stm32f1 -Wl,--defsym,_stack=0x20005000 \
+ -Wl,-T,bluepill.ld -nostartfiles -lc \
+ -Wl,-Map=mapfile -mthumb -mcpu=cortex-m3 -Wl,-gc-sections \
+ -L../libopencm3/lib
+LDFLAGS = $(LDFLAGS_BOOT)
+
+LDFLAGS += --specs=nosys.specs
+
+all: pill_6502.bin
+
+host_clean:
+ -$(Q)$(RM) pill_6502.bin
+
+OBJ = $(SRC:.c=.o)
+
+pill_6502.elf: version.h $(OBJ)
+ @echo " LD $@"
+ $(Q)$(CC) -o $@ $(OBJ) $(LDFLAGS)
+
+%.o: %.c
+ @echo " CC $<"
+ $(Q)$(CC) $(CFLAGS) -c $< -o $@
+
+%.bin: %.elf
+ @echo " OBJCOPY $@"
+ $(Q)$(OBJCOPY) -O binary $^ $@
+
+%.hex: %
+ @echo " OBJCOPY $@"
+ $(Q)$(OBJCOPY) -O ihex $^ $@
+
+.PHONY: clean host_clean FORCE
+
+clean: host_clean
+ $(Q)echo " CLEAN"
+ -$(Q)$(RM) -f *.o *.d *~ *.elf *.bin $(HOSTFILES)
+ -$(Q)$(RM) -f mapfile version.h
+
+version.h: FORCE
+ $(Q)echo " GIT version.h"
+ $(Q)echo "#define FIRMWARE_VERSION \"`git describe --always --dirty`\"" > $@
+
+-include *.d
diff --git a/src/bluepill.ld b/src/bluepill.ld
new file mode 100644
index 0000000..0c6c351
--- /dev/null
+++ b/src/bluepill.ld
@@ -0,0 +1,40 @@
+/*
+ * This file is part of the libopenstm32 project.
+ *
+ * Copyright (C) 2010 Thomas Otto
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see .
+ */
+
+/* Define memory regions. */
+MEMORY
+{
+ rom (rx) : ORIGIN = 0x08000000, LENGTH = 8K
+ data (rwx) : ORIGIN = 0x08002000, LENGTH = 128K-8K
+
+ ram (rwx) : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+SECTIONS
+{
+ .user_data (NOLOAD) :
+ {
+ . = ALIGN(4);
+ *(.user_data)
+ . = ALIGN(4);
+ } > data
+}
+
+/* Include the common ld script from libopenstm32. */
+INCLUDE libopencm3_stm32f1.ld
diff --git a/src/cdcacm.c b/src/cdcacm.c
new file mode 100644
index 0000000..4e441cf
--- /dev/null
+++ b/src/cdcacm.c
@@ -0,0 +1,264 @@
+// vim: tabstop=8 softtabstop=8 shiftwidth=8 noexpandtab
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2010 Gareth McMullin
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library. If not, see .
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+#include "cdcacm.h"
+#include "version.h"
+
+/* Serial ACM interface */
+#define CDCACM_PACKET_SIZE 128
+#define CDCACM_UART_ENDPOINT 0x03
+#define CDCACM_INTR_ENDPOINT 0x84
+
+static const struct usb_endpoint_descriptor uart_comm_endp[] = {{
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bEndpointAddress = CDCACM_INTR_ENDPOINT,
+ .bmAttributes = USB_ENDPOINT_ATTR_INTERRUPT,
+ .wMaxPacketSize = 16,
+ .bInterval = 255,
+}};
+
+static const struct usb_endpoint_descriptor uart_data_endp[] = {{
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bEndpointAddress = CDCACM_UART_ENDPOINT,
+ .bmAttributes = USB_ENDPOINT_ATTR_BULK,
+ .wMaxPacketSize = CDCACM_PACKET_SIZE,
+ .bInterval = 1,
+}, {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+ .bEndpointAddress = 0x80 | CDCACM_UART_ENDPOINT,
+ .bmAttributes = USB_ENDPOINT_ATTR_BULK,
+ .wMaxPacketSize = CDCACM_PACKET_SIZE,
+ .bInterval = 1,
+}};
+
+static const struct {
+ struct usb_cdc_header_descriptor header;
+ struct usb_cdc_call_management_descriptor call_mgmt;
+ struct usb_cdc_acm_descriptor acm;
+ struct usb_cdc_union_descriptor cdc_union;
+} __attribute__((packed)) uart_cdcacm_functional_descriptors = {
+ .header = {
+ .bFunctionLength = sizeof(struct usb_cdc_header_descriptor),
+ .bDescriptorType = CS_INTERFACE,
+ .bDescriptorSubtype = USB_CDC_TYPE_HEADER,
+ .bcdCDC = 0x0110,
+ },
+ .call_mgmt = {
+ .bFunctionLength =
+ sizeof(struct usb_cdc_call_management_descriptor),
+ .bDescriptorType = CS_INTERFACE,
+ .bDescriptorSubtype = USB_CDC_TYPE_CALL_MANAGEMENT,
+ .bmCapabilities = 0,
+ .bDataInterface = 2,
+ },
+ .acm = {
+ .bFunctionLength = sizeof(struct usb_cdc_acm_descriptor),
+ .bDescriptorType = CS_INTERFACE,
+ .bDescriptorSubtype = USB_CDC_TYPE_ACM,
+ .bmCapabilities = 2, /* SET_LINE_CODING supported*/
+ },
+ .cdc_union = {
+ .bFunctionLength = sizeof(struct usb_cdc_union_descriptor),
+ .bDescriptorType = CS_INTERFACE,
+ .bDescriptorSubtype = USB_CDC_TYPE_UNION,
+ .bControlInterface = 1,
+ .bSubordinateInterface0 = 2,
+ }
+};
+
+const struct usb_interface_descriptor uart_comm_iface[] = {{
+ .bLength = USB_DT_INTERFACE_SIZE,
+ .bDescriptorType = USB_DT_INTERFACE,
+ .bInterfaceNumber = 1,
+ .bAlternateSetting = 0,
+ .bNumEndpoints = 1,
+ .bInterfaceClass = USB_CLASS_CDC,
+ .bInterfaceSubClass = USB_CDC_SUBCLASS_ACM,
+ .bInterfaceProtocol = USB_CDC_PROTOCOL_AT,
+ .iInterface = 4,
+
+ .endpoint = uart_comm_endp,
+
+ .extra = &uart_cdcacm_functional_descriptors,
+ .extralen = sizeof(uart_cdcacm_functional_descriptors)
+}};
+
+const struct usb_interface_descriptor uart_data_iface[] = {{
+ .bLength = USB_DT_INTERFACE_SIZE,
+ .bDescriptorType = USB_DT_INTERFACE,
+ .bInterfaceNumber = 2,
+ .bAlternateSetting = 0,
+ .bNumEndpoints = 2,
+ .bInterfaceClass = USB_CLASS_DATA,
+ .bInterfaceSubClass = 0,
+ .bInterfaceProtocol = 0,
+ .iInterface = 0,
+
+ .endpoint = uart_data_endp,
+}};
+
+const struct usb_iface_assoc_descriptor uart_assoc = {
+ .bLength = USB_DT_INTERFACE_ASSOCIATION_SIZE,
+ .bDescriptorType = USB_DT_INTERFACE_ASSOCIATION,
+ .bFirstInterface = 1,
+ .bInterfaceCount = 2,
+ .bFunctionClass = USB_CLASS_CDC,
+ .bFunctionSubClass = USB_CDC_SUBCLASS_ACM,
+ .bFunctionProtocol = USB_CDC_PROTOCOL_AT,
+ .iFunction = 0,
+};
+
+static void cdcacm_set_modem_state(usbd_device *dev, int iface, bool dsr, bool dcd)
+{
+ char buf[10];
+ struct usb_cdc_notification *notif = (void*)buf;
+ /* We echo signals back to host as notification */
+ notif->bmRequestType = 0xA1;
+ notif->bNotification = USB_CDC_NOTIFY_SERIAL_STATE;
+ notif->wValue = 0;
+ notif->wIndex = iface;
+ notif->wLength = 2;
+ buf[8] = (dsr ? 2 : 0) | (dcd ? 1 : 0);
+ buf[9] = 0;
+ usbd_ep_write_packet(dev, 0x82 + iface, buf, 10);
+}
+
+static int cdcacm_control_request(usbd_device *dev,
+ struct usb_setup_data *req, uint8_t **buf, uint16_t *len,
+ void (**complete)(usbd_device *dev, struct usb_setup_data *req))
+{
+ (void)dev;
+ (void)complete;
+ (void)buf;
+ (void)len;
+
+ switch(req->bRequest) {
+ case USB_CDC_REQ_SET_CONTROL_LINE_STATE:
+ cdcacm_set_modem_state(dev, req->wIndex, true, true);
+ return 1;
+ case USB_CDC_REQ_SET_LINE_CODING:
+ if(*len < sizeof(struct usb_cdc_line_coding))
+ return 0;
+
+ return 1;
+ }
+ return 0;
+}
+
+static void send_chunked_blocking(char *buf, int len, usbd_device *dev, int endpoint, int max_packet_length) {
+ uint16_t bytes_written = 0;
+ uint16_t total_bytes_written = 0;
+ uint16_t bytes_remaining = len;
+
+ do {
+ uint16_t this_length = bytes_remaining;
+ if (this_length > max_packet_length) this_length = max_packet_length;
+
+ bytes_written = usbd_ep_write_packet(dev, endpoint, buf + total_bytes_written, this_length);
+ bytes_remaining -= bytes_written;
+ total_bytes_written += bytes_written;
+ } while (bytes_remaining > 0);
+}
+
+extern char *process_serial_command(char *buf, int len);
+
+static void usbuart_usb_out_cb(usbd_device *dev, uint8_t ep)
+{
+ (void)ep;
+
+ char buf[CDCACM_PACKET_SIZE];
+ char reply_buf[256];
+
+ static char typing_buf[2048] = {0};
+ static int typing_index = 0;
+
+ int len = usbd_ep_read_packet(dev, CDCACM_UART_ENDPOINT,
+ buf, CDCACM_PACKET_SIZE);
+
+
+ int j = 0;
+ for(int i = 0; i < len; i++) {
+ gpio_toggle(GPIOC, GPIO13);
+
+ // Echo back what was typed
+ // Enter sends a CR, but an LF is needed to advance to next line
+ if (buf[i] == '\r') reply_buf[j++] = '\n';
+ reply_buf[j++] = buf[i];
+
+ typing_buf[typing_index++] = buf[i];
+
+ if (buf[i] == '\r' || buf[i] == '\n') {
+ char *response = process_serial_command(typing_buf, typing_index);
+ typing_index = 0;
+
+ for (size_t k = 0; k < strlen(response); ++k) {
+ reply_buf[j++] = response[k];
+ }
+
+ // prompt
+ reply_buf[j++] = '>';
+ reply_buf[j++] = ' ';
+ }
+ }
+
+ send_chunked_blocking(reply_buf, j, dev, CDCACM_UART_ENDPOINT, CDCACM_PACKET_SIZE);
+}
+
+static void usbuart_usb_in_cb(usbd_device *dev, uint8_t ep)
+{
+ (void) dev;
+ (void) ep;
+}
+
+void cdcacm_set_config(usbd_device *dev, uint16_t wValue)
+{
+ (void) wValue;
+
+ /* Serial interface */
+ usbd_ep_setup(dev, CDCACM_UART_ENDPOINT, USB_ENDPOINT_ATTR_BULK,
+ CDCACM_PACKET_SIZE, usbuart_usb_out_cb);
+ usbd_ep_setup(dev, 0x80 | CDCACM_UART_ENDPOINT, USB_ENDPOINT_ATTR_BULK,
+ CDCACM_PACKET_SIZE, usbuart_usb_in_cb);
+ usbd_ep_setup(dev, CDCACM_INTR_ENDPOINT, USB_ENDPOINT_ATTR_INTERRUPT, 16, NULL);
+
+ usbd_register_control_callback(dev,
+ USB_REQ_TYPE_CLASS | USB_REQ_TYPE_INTERFACE,
+ USB_REQ_TYPE_TYPE | USB_REQ_TYPE_RECIPIENT,
+ cdcacm_control_request);
+
+ /* Notify the host that DCD is asserted.
+ * Allows the use of /dev/tty* devices on *BSD/MacOS
+ */
+ cdcacm_set_modem_state(dev, 2, true, true);
+}
+
+
diff --git a/src/cdcacm.h b/src/cdcacm.h
new file mode 100644
index 0000000..22183b4
--- /dev/null
+++ b/src/cdcacm.h
@@ -0,0 +1,9 @@
+// vim: tabstop=8 softtabstop=8 shiftwidth=8 noexpandtab
+
+#include
+
+extern const struct usb_interface_descriptor uart_comm_iface[];
+extern const struct usb_interface_descriptor uart_data_iface[];
+extern const struct usb_iface_assoc_descriptor uart_assoc;
+
+void cdcacm_set_config(usbd_device *dev, uint16_t wValue);
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..27b6249
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,143 @@
+// vim: tabstop=8 softtabstop=8 shiftwidth=8 noexpandtab
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2010 Gareth McMullin
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library. If not, see .
+ */
+
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+#include
+
+#include "cdcacm.h"
+#include "version.h"
+
+static usbd_device *usbd_dev;
+
+const struct usb_device_descriptor dev_descr = {
+ .bLength = USB_DT_DEVICE_SIZE,
+ .bDescriptorType = USB_DT_DEVICE,
+ .bcdUSB = 0x0200,
+ .bDeviceClass = 0,
+ .bDeviceSubClass = 0,
+ .bDeviceProtocol = 0,
+ .bMaxPacketSize0 = 64,
+ .idVendor = 0x05ac,
+ .idProduct = 0x2227,
+ .bcdDevice = 0x0200,
+ .iManufacturer = 1,
+ .iProduct = 2,
+ .iSerialNumber = 3,
+ .bNumConfigurations = 1,
+};
+
+
+const struct usb_interface ifaces[] = {{
+ .num_altsetting = 1,
+ .iface_assoc = &uart_assoc,
+ .altsetting = uart_comm_iface,
+}, {
+ .num_altsetting = 1,
+ .altsetting = uart_data_iface,
+}};
+
+const struct usb_config_descriptor config = {
+ .bLength = USB_DT_CONFIGURATION_SIZE,
+ .bDescriptorType = USB_DT_CONFIGURATION,
+ .wTotalLength = 0,
+ .bNumInterfaces = sizeof(ifaces)/sizeof(ifaces[0]),
+ .bConfigurationValue = 1,
+ .iConfiguration = 0,
+ .bmAttributes = 0xC0,
+ .bMaxPower = 0x32,
+
+ .interface = ifaces,
+};
+
+static const char *usb_strings[] = {
+ "satoshinm",
+ "Pill 6502",
+ "6502",
+ "Pill 6502 UART Port",
+};
+
+void sys_tick_handler(void)
+{
+ gpio_toggle(GPIOC, GPIO13);
+}
+
+
+static void usb_set_config(usbd_device *dev, uint16_t wValue)
+{
+ cdcacm_set_config(dev, wValue);
+}
+
+char *process_serial_command(char *buf, int len) {
+ (void) len;
+
+ if (buf[0] == 'v') {
+ return "Pill 6502 version " FIRMWARE_VERSION;
+ } else {
+ return "invalid command, try ? for help";
+ }
+
+ return "";
+}
+
+static void setup_clock(void) {
+ rcc_clock_setup_in_hsi_out_48mhz();
+ rcc_periph_clock_enable(RCC_GPIOC);
+
+ systick_set_clocksource(STK_CSR_CLKSOURCE_AHB_DIV8);
+ /* SysTick interrupt every N clock pulses: set reload to N-1
+ * Period: N / (72 MHz / 8 )
+ * */
+ systick_set_reload(8999); // 1 ms
+ systick_interrupt_enable();
+ systick_counter_enable();
+}
+
+static void setup_gpio(void) {
+ // Built-in LED on blue pill board, PC13
+ gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_2_MHZ,
+ GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
+ gpio_set(GPIOC, GPIO13);
+
+}
+
+/* Buffer to be used for control requests. */
+uint8_t usbd_control_buffer[128];
+
+int main(void)
+{
+ setup_clock();
+ setup_gpio();
+
+ usbd_dev = usbd_init(&st_usbfs_v1_usb_driver, &dev_descr, &config, usb_strings,
+ sizeof(usb_strings)/sizeof(char *),
+ usbd_control_buffer, sizeof(usbd_control_buffer));
+ usbd_register_set_config_callback(usbd_dev, usb_set_config);
+
+ while (1)
+ usbd_poll(usbd_dev);
+}
+