forked from Apple-2-HW/TommyPROM
118 lines
6.1 KiB
Markdown
118 lines
6.1 KiB
Markdown
---
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title: Overview
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description: "TommyPROM Arduino based programmer for 28C256 EEPROMs"
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has_children: false
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nav_order: 1
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---
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# TommyPROM - An Arduino-based EEPROM programmer
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This is a simple EEPROM programmer and reader that can be assembled using an Arduino and a
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few additional parts. It has been successfully built using the Arduino UNO, Nano and
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Boarduino models.
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The original code was specific to the 28C256 32Kx8 EEPROM, but it has been extended to also support Intel 8755A EPROMS and some 29C010 Flash.
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## Design
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The 28C design can be used with other 5V EEPROMS as well. Many 5V chips, including UV
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EPROMs, such as the 2716, 2764, 27C2001 and 27C040, can be read, but not written, with the
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basic hardware. Some pin changes may be needed to get the signals to the correct pins on
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the device. See the [Extending the design](extending) page for details on suggested
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hardware and software changes needed to support new EPROM and EEPROM families.
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The PROM-specific code is modular and can be easily adapted to support additional devices.
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There are currently drivers and hardware designs for 28C series EEPROMS and the Intel
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8755A EPROM.
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Some 29C series chips, like the 29C010 can be written with the 28C hardware. The 29C
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series only differs from the 28C in that the 29C chips erase and write an entire sector at
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a time. The 29C010 and some 29C020 chips use a 128 byte sector, which matches the XModem
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buffer in the current code. Other 29C020s and all 29C040s use a 256 byte sector and
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cannot be written without code changes to buffer up an entire 256 byte block of data
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before writing.
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Features include:
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* Simple hardware design that can be assembled on a breadboard.
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* ROM images transfers using XMODEM - no special host client needed.
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* Support for fast block EEPROM writes - a 32K EEPROM will program in just a few seconds.
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* Optimized code that supports the timing requirements needed to unlock the 28C series Software Protection Algorithm.
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* Modular software design to easily support other EEPROM and EPROM families.
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The [hardware](hardware) page has descriptions of the hardware designs and links to schematics. The [software](software) page has class definitions and more information
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on the software design.
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The project was inspired by the
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[MEEPROMMER programmer](http://www.ichbinzustaendig.de/dev/meeprommer-en).
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## Compiling
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Open the TommyPROM.ino file in the Arduino IDE. It should automatically open the cpp and h
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files as well. The default code programs 28C series chips using Arduino Nano hardware. To
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use this version, just compile and upload it to the Arduino.
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**Note well** that this code has been optimized for the Aduino UNO and Nano hardware so
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that it can run quickly enough to meet 28C series chip timing requirements for SDP
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unlocking. To use different Arduino hardware, like the Micro, the board-specific code in
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PromDevice.cpp and PromAddressDriver.cpp must be change to match the port mappings between
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the ATmega chip and the Arduino I/O pins.
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To use the 8755A version of the code and matching hardware, uncomment PROM_IS_8755A and
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comment out the other PROM_IS_xx choices in Configure.h.
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## Operation
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To use the programmer, connect the Arduino USB to the host computer and run a terminal
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program, such as TeraTerm (Windows) or Minicom (Linux). The Arduino development Serial
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Monitor can also be used as a terminal initially, but it does not support XMODEM
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transfers, so the READ and WRITE commands can't be used.
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Set the terminal's serial parameters to 115200 baud, 8 bits, no parity, 1 stop bit to
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match the Arduino. Press the Enter key. If the connection is successful, TommyPROM will
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display a menu of options.
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Most of the commands take a start address parameter, always entered as 1 to 5 hex
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characters. Leading zeros are not required. If needed, the end address parameter is also
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in hex. Parameters are separated by a space. For example, either of the commands:
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d0000 01ff
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d0 1ff
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will dump memory from 0000H to 01ffH. Note that commands and parameters can be entered in
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uppercase or lowercase.
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The R command is used to read from a PROM and save a binary image on the host. The W
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command receives a file from the host and writes (burns) it into the device. The R
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command needs a start and end address. The W command determines the end address from the
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received file size.
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The READ and WRITE commands both use XMODEM CRC to complete the file transfers. Many
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terminal programs default to XMODEM Checksum format, so be sure to select XMODEM CRC as
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the format. Once the READ or WRITE command is issued to the programmer, the transfer must
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be started on the host program.
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The files used for READ and WRITE are simple binary images. This can be created directly
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by [asm85](http://github.com/TomNisbet/asm85) or can be converted from S-record or Intel
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HEX using an external utility.
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## Troubleshooting
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* Verify that the Arduino type you are using is a supported board or that its I/O port definitions match one of the supported boards. Some other Arduino boards, like the
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Duemilanove, appear to be compatible but have not been tested. Others, like the Micro,
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have different port mappings and definitely will not work without software changes.
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* If the code doesn't appear to be working, concentrate on the read operations first to
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verify that the data and address paths are good.
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* 28C series EEPROMS, like the X28C256, sometimes ship from the factory with Data
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Protection enabled. Use the UNLOCK command to disable this. See the
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[28C256 Notes](28C256-notes) for more information.
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* Re-check all hardware connections and verify the the control pins are going to the
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Arduino pins that match the definitions in the code.
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* This repo contains a standalone program called HardwareVerify that allows low-level
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access to the address, data, and control lines through a menu-driven interface. See the [troubleshooting](troubleshooting) section for more tips.
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## Further Work
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* [ ]Add a new PromDevice class for 27 series EPROMS.
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* [x] Additional error checking in the CmdLine code.
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