Cosam
@cosam-the-great.bsky.social
Messing with retro stuff, with varying levels of success.
https://ko-fi.com/cosam
https://www.youtube.com/@cosam2
https://ko-fi.com/cosam
https://www.youtube.com/@cosam2
Debugging the SFC to CD mechacon interface. Timing to work out on the PLD side to get reliable reads/writes each way. The scope shows the individual nibbles of an ACCESS command being transferred to an ATMega microcontroller that's standing in for the real mechacon chip.
November 14, 2025 at 5:12 PM
Debugging the SFC to CD mechacon interface. Timing to work out on the PLD side to get reliable reads/writes each way. The scope shows the individual nibbles of an ACCESS command being transferred to an ATMega microcontroller that's standing in for the real mechacon chip.
Some progress on the Nintendo PlayStation: some programmable logic acts as a bridge between SFC and CD hardware. Set up in a loopback configuration, the BIOS now thinks it's talking to the mechacon MCU. Mock firmware is ready to go once this part is debugged.
November 12, 2025 at 4:58 PM
Some progress on the Nintendo PlayStation: some programmable logic acts as a bridge between SFC and CD hardware. Set up in a loopback configuration, the BIOS now thinks it's talking to the mechacon MCU. Mock firmware is ready to go once this part is debugged.
If you don't manage to find one, this is coming along quite nicely...
July 12, 2025 at 5:26 PM
If you don't manage to find one, this is coming along quite nicely...
ITYF that's totally a drill.
June 30, 2025 at 8:42 AM
ITYF that's totally a drill.
Thanks to the tireless efforts of the community, the Neptune "region flicker" issue has been diagnosed and fixed! To commemorate in true #Sega style, here's a service bulletin, complete with traditional inconsistent fonts and dodgy layout.
June 4, 2025 at 9:35 AM
Thanks to the tireless efforts of the community, the Neptune "region flicker" issue has been diagnosed and fixed! To commemorate in true #Sega style, here's a service bulletin, complete with traditional inconsistent fonts and dodgy layout.
Also the slowest ISA machine I have is a 486 with a 8 Mhz bus clock which is way too fast. Unused flip-flop on the board bodged in as a frequency divider brings it into spec 😅 Will try to work this into the board as a configurable option.
April 14, 2025 at 1:33 PM
Also the slowest ISA machine I have is a 486 with a 8 Mhz bus clock which is way too fast. Unused flip-flop on the board bodged in as a frequency divider brings it into spec 😅 Will try to work this into the board as a configurable option.
Reasonably convincing except for the lack of volume knob and ISA bracket. No actual audio coming out of it yet, I suspect my AliExpress special AY chips may not be 100% genuine...
April 14, 2025 at 1:33 PM
Reasonably convincing except for the lack of volume knob and ISA bracket. No actual audio coming out of it yet, I suspect my AliExpress special AY chips may not be 100% genuine...
It's a busy 6-layer design, 4 signal, 1 ground, 1 VCC. Pretty advanced for the time.
March 28, 2025 at 11:47 AM
It's a busy 6-layer design, 4 signal, 1 ground, 1 VCC. Pretty advanced for the time.
Pretty niche this one, even for me. My non-running A530 started losing pads during troubleshooting, which was going slowly without schematics. Hopefully this will kill two birds with one stone.
March 28, 2025 at 11:43 AM
Pretty niche this one, even for me. My non-running A530 started losing pads during troubleshooting, which was going slowly without schematics. Hopefully this will kill two birds with one stone.
YouTuber: "You will never own this."
PCB reproducer/reverse engineer/general weirdo: "Hold my beer."
PCB reproducer/reverse engineer/general weirdo: "Hold my beer."
March 25, 2025 at 9:33 AM
YouTuber: "You will never own this."
PCB reproducer/reverse engineer/general weirdo: "Hold my beer."
PCB reproducer/reverse engineer/general weirdo: "Hold my beer."
Fun little challenge for SMW veterans: complete the game as small Mario, no power ups or mid-level checkpoints. It's tricky but not as bad as you might expect.
March 13, 2025 at 12:12 AM
Fun little challenge for SMW veterans: complete the game as small Mario, no power ups or mid-level checkpoints. It's tricky but not as bad as you might expect.
It doesn't do much but here's a simple register write and it reads back as the same value. SFC and BIOS are talking to actual CD hardware!
January 27, 2025 at 5:50 PM
It doesn't do much but here's a simple register write and it reads back as the same value. SFC and BIOS are talking to actual CD hardware!
Slightly different revision (R instead of AR) but datasheet suggests it's pin-compatible, so let's stick it on...
January 27, 2025 at 5:49 PM
Slightly different revision (R instead of AR) but datasheet suggests it's pin-compatible, so let's stick it on...
Junk DD-10, busted screen, jammed drive mech, horrible gummy coating peeling off... but goodies lurk inside...
January 27, 2025 at 5:48 PM
Junk DD-10, busted screen, jammed drive mech, horrible gummy coating peeling off... but goodies lurk inside...
This flex adapts the footprint for the unobtainium CXD1800 to the functionally equivalent CXD1196 as found in some models of Data Discman. Junk donors are on their way so the diagnostic should be able to talk to a real chip when fitted.
January 25, 2025 at 11:15 PM
This flex adapts the footprint for the unobtainium CXD1800 to the functionally equivalent CXD1196 as found in some models of Data Discman. Junk donors are on their way so the diagnostic should be able to talk to a real chip when fitted.
Some hackery with a GAL to do address decoding and buffer control. This allows the SFC to access the CD hardware and will eventually be part of the "mystery" glue logic.
January 25, 2025 at 11:14 PM
Some hackery with a GAL to do address decoding and buffer control. This allows the SFC to access the CD hardware and will eventually be part of the "mystery" glue logic.
Very early steps towards getting the CD hardware working. This is the BIOS diagnostic for the CXD1800 CD decoder chip. The SFC is reading values I have hard-wired onto the CD side of the data bus for testing purposes.
January 25, 2025 at 11:14 PM
Very early steps towards getting the CD hardware working. This is the BIOS diagnostic for the CXD1800 CD decoder chip. The SFC is reading values I have hard-wired onto the CD side of the data bus for testing purposes.
Board now runs under its own power (OK, wrong jack...). RGB video is sorted (no more external RGB amp hack) and audio is there but not 100% yet. No mean feat as A/V is all different to normal SFC or SNES.
January 15, 2025 at 8:57 PM
Board now runs under its own power (OK, wrong jack...). RGB video is sorted (no more external RGB amp hack) and audio is there but not 100% yet. No mean feat as A/V is all different to normal SFC or SNES.
Don't get too excited. At the moment this is just the world's most overcomplicated yet incomplete Super Famicom.
January 1, 2025 at 4:35 PM
Don't get too excited. At the moment this is just the world's most overcomplicated yet incomplete Super Famicom.
Just a little side project: simple tester for Mega Drive/Genesis controllers. github.com/Board-Folk/M...
December 20, 2024 at 7:25 PM
Just a little side project: simple tester for Mega Drive/Genesis controllers. github.com/Board-Folk/M...
I really should stop trying to recreate PCBs whenever someone models a case for an unreleased console... @weskmods.bsky.social's fault this time.
November 8, 2024 at 3:41 PM
I really should stop trying to recreate PCBs whenever someone models a case for an unreleased console... @weskmods.bsky.social's fault this time.