Search found 15 matches

by cmorley
Sun Aug 18, 2019 3:55 pm
Forum: 8 BIT CORNER
Topic: 27C400/27C800 EPROM emulator
Replies: 24
Views: 1358

Re: 27C400/27C800 EPROM emulator

Working well in a rev 5 Amiga 500. The data buffers are HCT so 5v CMOS output levels - won't require pull ups like a 27C400 does in a rev 5... The wire goes to the _RESET signal to get ROM swithcing from the keyboard with ctrl+ A +A. (ROM switching can also be done via the USB which might be useful ...
by cmorley
Sun Aug 18, 2019 3:29 pm
Forum: 8 BIT CORNER
Topic: 27C400/27C800 EPROM emulator
Replies: 24
Views: 1358

Re: 27C400/27C800 EPROM emulator

I did a PCB to adapter to an Acorn Master MOS (1Mbit 128Kx8 mask ROM). Just sent the PCB order off.
Master MOS adapter.jpg
Master MOS adapter.jpg (133.09 KiB) Viewed 26 times
by cmorley
Wed Aug 14, 2019 6:36 pm
Forum: PC FOR SALE & WANTED
Topic: SOLD - A500/A2000 megachip
Replies: 2
Views: 90

Re: A500/A2000 megachip

Sure you can have it. I replied to you PM.

Chris
by cmorley
Sun Aug 11, 2019 7:00 pm
Forum: 8 BIT CORNER
Topic: 27C400/27C800 EPROM emulator
Replies: 24
Views: 1358

Re: 27C400/27C800 EPROM emulator

Ha. Typical...

I'm building up the balance of the 10x PCBs I got for these prototypes and I have run out of 100nF 0402 caps! I'll put a Mouser order in tomorrow.

So looking like posting out back end of next week. I'll PM people to arrange the details with them.
by cmorley
Sun Aug 11, 2019 9:41 am
Forum: PC FOR SALE & WANTED
Topic: SOLD - A500/A2000 megachip
Replies: 2
Views: 90

SOLD - A500/A2000 megachip

Not PC but not Atari so I picked this category. I bought one of tuxbar81 on amibay's MegAChip to test compatibility with my A500 2MB RAM. Short story they clash - I'm not surprised but now I know for certain! I am not going to fit it to my A2000 motherboard so now I have an assembled and tested MegA...
by cmorley
Tue Aug 06, 2019 1:10 pm
Forum: 8 BIT CORNER
Topic: 27C400/27C800 EPROM emulator
Replies: 24
Views: 1358

Re: 27C400/27C800 EPROM emulator

Update: Firmware ported from the dev board to the prototype. Pinouts changed on the CPLD and STM32 and I altered the signal routing through the CPLD but so far so good. It's in an A500 now with 3.1.4, DiagROM, 3.1 and 1.3 programmed in & ROM switching works. Currently has the SWDIO header soldered o...
by cmorley
Sun Aug 04, 2019 11:27 am
Forum: TF360
Topic: TF360 Status
Replies: 39
Views: 2042

Re: TF360 Status

terriblefire wrote:
Sun Aug 04, 2019 9:50 am
This one will be worth it.. just waiting for my toast.
Does the 060 get that hot?!
by cmorley
Fri Aug 02, 2019 5:58 pm
Forum: 8 BIT CORNER
Topic: 27C400/27C800 EPROM emulator
Replies: 24
Views: 1358

Re: 27C400/27C800 EPROM emulator

Right so after a couple weeks of inactivity I'll get on with porting the firmware from my dev board to this prototype this weekend & do some basic tests to check they actually work and there is nothing wrong with the PCBs or schematic. I'll then solder a few up and post them out to those who voulent...
by cmorley
Tue Jul 16, 2019 6:57 am
Forum: 8 BIT CORNER
Topic: 27C400/27C800 EPROM emulator
Replies: 24
Views: 1358

Re: 27C400/27C800 EPROM emulator

Looks like a nice product and it's up to modern standards / sizes. I'm very much interested in testing it. What would be the cost and what parts are used? I may have quite a bit of the parts in stock and do have soldering skills. Keep up the good work please ! :D What machine would you test with? C...
by cmorley
Mon Jul 15, 2019 2:01 pm
Forum: 8 BIT CORNER
Topic: 27C400/27C800 EPROM emulator
Replies: 24
Views: 1358

Re: 27C400/27C800 EPROM emulator

I have 70ns and 55ns FLASH to test with. We lose a little margin with the buffers but gain some because the chips are faster than their datasheet say.

Worst case 80ns (70ns FLASH). Very much faster than most retro computers would need.