Welcome Noel
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Mark
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- 13 Dec 2013 22:33
- Forum: INTRODUCE YOURSELF
- Topic: Hi all!
- Replies: 3
- Views: 5565
- 08 Dec 2013 19:54
- Forum: MAGROM
- Topic: Who wants a MAGROM board?
- Replies: 21
- Views: 29666
Re: Who wants a MAGROM board?
V5 is built and lightly tested, it seems to be working fine. It's now down to 6 chips. It has all of Mark's suggestions implemented, plus *grom instead of the 74xx138 doing rom 7 detection. The MTX500 I tested it on has one of Andy's Rememorizor PAL's fitted, but that shouldn't make any difference....
- 07 Dec 2013 14:58
- Forum: GENERAL DISCUSSIONS
- Topic: "The Source" - Second Printing, now taking orders . . . .
- Replies: 12
- Views: 13467
Re: "The Source" - Second Printing, now taking orders . . .
Hi Dave
I would be interested, so yes please
(I think I have already messaged you via Facebook, but just wanted to remind you )
Mark
I would be interested, so yes please
(I think I have already messaged you via Facebook, but just wanted to remind you )
Mark
- 06 Dec 2013 01:33
- Forum: GENERAL DISCUSSIONS
- Topic: It's a bit quiet in here...
- Replies: 3
- Views: 4993
Re: It's a bit quiet in here...
..is everyone making plans for Xmas? So far only busy putting up decorations (haven't found time to do any other Christmas stuff so far...), but also busy with other retro computers, electronics, fixing the gates, plus loads of other real life stuff... PS, do we need an off topic forum? ;) Yes! :!:...
- 30 Nov 2013 22:30
- Forum: MAGROM
- Topic: Who wants a MAGROM board?
- Replies: 21
- Views: 29666
Re: Who wants a MAGROM board?
@ Martin, if a revised design is produced whereby the /ROM7 signal is generated on board, you may also want to consider adding !RE/CPM to the logic. Use the last free OR gate in U1 with one input being !RE/CPM and the other input being A15. Then route the output to U2B (74LS00) in place of the A15 s...
- 30 Nov 2013 22:03
- Forum: MAGROM
- Topic: Who wants a MAGROM board?
- Replies: 21
- Views: 29666
Re: Who wants a MAGROM board?
Off topic a bit, but... Dave, while on that web page of yours I noticed some errors with the PAL logic equations. The second line for the /CEA equation should have A13 true and not inverted. Also both the equations for /CE64 should have A13 true and not inverted. I have not checked any others, but y...
- 30 Nov 2013 19:26
- Forum: MAGROM
- Topic: Who wants a MAGROM board?
- Replies: 21
- Views: 29666
Re: Who wants a MAGROM board?
Not having looked at a schematic of a game cartridge (let alone getting my hands on a real game cartridge), I cannot be sure if they use /GROM. However, looking at schematic for the MTX main board, these are my thoughts... First of all, keep in mind that R0, R1 and R2 originate from a 74LS273 latch ...
- 30 Nov 2013 00:57
- Forum: MAGROM
- Topic: Who wants a MAGROM board?
- Replies: 21
- Views: 29666
Re: Who wants a MAGROM board?
Okay, this draft amendment schematic reduces the chip count by two :D . U1, U6, U8 stay the same type (but U1 and U8 have some wiring changes) as per Martin's schematic. U2 has now been changed to a 74LS00 NAND chip. U3 has been deleted. U4 has now been changed to a 74LS30 NAND chip. U5 has now been...
- 29 Nov 2013 11:21
- Forum: MAGROM
- Topic: Who wants a MAGROM board?
- Replies: 21
- Views: 29666
Re: Who wants a MAGROM board?
Of course
Details soon...
Mark
Details soon...
Mark
- 29 Nov 2013 03:28
- Forum: MAGROM
- Topic: Who wants a MAGROM board?
- Replies: 21
- Views: 29666
Re: Who wants a MAGROM board?
About the ROM board. Having had a quick look, I think even if we stay with "TTL" logic chips and one ROM, the chip count can be reduced by at least one, may be more .
Mark
Mark