AtomBusMon/target
David Banks b9d6359be4 Checked in initial work on lx9_dave target (see full comment)
The .ucf files look like they are for a completely different board
(the lx9 starter board, not the epizza board). So these need to be
reworked completely.

Also, the following signals needs adding to the top level 6502 design:
- OEAH (output)
- OEAL (output)
- OED  (output)
- ML   (output)
- VP   (output)
- BE   (input)

The system will not work without some attention to these.

Minimally, in the FPGA design we can tie them as follows:
- OEAH (output) - set to 0 (address bus always enabled)
- OEAL (output) - set to 0 (ditto)
- OED  (output) - set to !phi2 (data bus driven in second half of clock)
- ML   (output) - set output to 1 (and fit P3 link between pins 2 and 3)
- VP   (output) - set output to 1 (and don't fit P4 link)
- BE   (input)  - ignore input

The current adapter design does not fully support the implementation of BE
as it does not provide a way to tristate RNW. That would require the addition
of a seperate level shifter, e.g. a 74LVC1G125

Change-Id: I1bf11c5ef8318c5ebfa942cb4bd07f750d0b370d
2018-11-20 09:42:58 +00:00
..
common Updated Makefile for 64-bit build 2018-02-15 13:05:49 +00:00
godil_250 LX9 support: massive refactor of the build system 2017-07-26 14:59:20 +01:00
godil_500 LX9 support: massive refactor of the build system 2017-07-26 14:59:20 +01:00
lx9_dave Checked in initial work on lx9_dave target (see full comment) 2018-11-20 09:42:58 +00:00
lx9_jason Pinout change for LX9: DIP pins 37 and 38 needed swapping 2017-08-09 16:37:41 +01:00
lx9_jason_flipped Added build for a flipped version of Jason's level shifter, so USB comes out at the pin 1 end (better for Beeb) 2017-08-09 18:16:11 +01:00
Makefile Added lx9_jason_flipped to build 2017-09-22 22:57:54 +01:00