Search found 32 matches

by regiscaelus
Sat Feb 03, 2024 3:30 am
Forum: SNESdev
Topic: SRAM doesn't working with NPN and flash S29GL064
Replies: 20
Views: 1187

Re: SRAM doesn't working with NPN and flash S29GL064

OK, let me know if you want le review your design. You can send me information in PM if you like.
by regiscaelus
Fri Feb 02, 2024 4:52 pm
Forum: SNESdev
Topic: SRAM doesn't working with NPN and flash S29GL064
Replies: 20
Views: 1187

Re: SRAM doesn't working with NPN and flash S29GL064

Yes, it'll need to be tidied up a bit. What PCB are you working from by the way?
by regiscaelus
Fri Feb 02, 2024 7:55 am
Forum: SNESdev
Topic: SRAM doesn't working with NPN and flash S29GL064
Replies: 20
Views: 1187

Re: SRAM doesn't working with NPN and flash S29GL064

Don't worry, it should be correct. A15 for LoROM is always high when accessing the ROM and that's why output Y3 is driven low. When ever LoROM is not accessed, i.e. A15 = 0, then it gives access to the SRAM. What game are you using at the moment? I can check the memory allocation to make sure it mat...
by regiscaelus
Fri Feb 02, 2024 6:52 am
Forum: SNESdev
Topic: SRAM doesn't working with NPN and flash S29GL064
Replies: 20
Views: 1187

Re: SRAM doesn't working with NPN and flash S29GL064

No, VCC to SRAM is between R4 and R5 on my schematics. If you used it where you suggested, R4 would limit current too much for the chip to operate. Also forgot to mention, that placing VCC to SRAM where you suggested would actually unpower the chip when the transistor conducts which will make you lo...
by regiscaelus
Fri Feb 02, 2024 1:01 am
Forum: SNESdev
Topic: SRAM doesn't working with NPN and flash S29GL064
Replies: 20
Views: 1187

Re: SRAM doesn't working with NPN and flash S29GL064

SNES_Cart.pdf
(72.89 KiB) Downloaded 14 times
Start with getting LoROM working and then we'll look at the HiROM configuration.
by regiscaelus
Thu Feb 01, 2024 11:11 pm
Forum: SNESdev
Topic: SRAM doesn't working with NPN and flash S29GL064
Replies: 20
Views: 1187

Re: SRAM doesn't working with NPN and flash S29GL064

Yes, pin 15 should be connected to 1y0 (pin 4) and not 1y2 (pin 6). That's the mistake.
by regiscaelus
Thu Feb 01, 2024 2:07 pm
Forum: SNESdev
Topic: Max sprites on-screen using the following approach . . .
Replies: 9
Views: 935

Re: Max sprites on-screen using the following approach . . .

You reach the 128 object table limit after 32 pixels i.e. 4 rows of 8x8px sprites. Then, you would need to turn off rendering to write a vertical offset on each objectif in the table using dma as it would be the simplest and fastest way of doing it and then reenable rendering. Dma will write 1365/8 ...
by regiscaelus
Thu Feb 01, 2024 1:20 pm
Forum: SNESdev
Topic: SRAM doesn't working with NPN and flash S29GL064
Replies: 20
Views: 1187

Re: SRAM doesn't working with NPN and flash S29GL064

Try changing R1 to 33k. You also missed a pull-up resistor on the emitter connected to 5v (and not vcc2). I think you can also use 33k there.
by regiscaelus
Thu Feb 01, 2024 6:23 am
Forum: SNESdev
Topic: SRAM doesn't working with NPN and flash S29GL064
Replies: 20
Views: 1187

Re: SRAM doesn't working with NPN and flash S29GL064

Would you mind sharing your schematics to be sure?
by regiscaelus
Wed Nov 01, 2023 3:54 pm
Forum: SNESdev
Topic: S-SCPU Schematics
Replies: 5
Views: 2287

Re: S-SCPU Schematics

Panic's over, it looks like my schematics were correct after all. I have reorganised the simulation to closer match the schematics and have seen the expect behaviour found in available documentation. Note added to my schematics: "Simulation shows that when VBLANK ends, HDMA will enable HDMA cha...
by regiscaelus
Mon Oct 30, 2023 11:17 am
Forum: SNESdev
Topic: S-SCPU Schematics
Replies: 5
Views: 2287

Re: S-SCPU Schematics

Hi all, just to let you know that significant progress has been made on the schematics and most of it seems to make sense. However, I have come unstuck with regards to the HDMA section. I must have a made a mistake as the HDMA does not switch between table reads and data transfers (which ever comes ...
by regiscaelus
Wed Jun 14, 2023 11:32 am
Forum: SNESdev
Topic: S-SCPU Schematics
Replies: 5
Views: 2287

Re: S-SCPU Schematics

Thanks for this. I knew someone would have done this already but didn't know where to look.
by regiscaelus
Wed Jun 14, 2023 2:26 am
Forum: SNESdev
Topic: S-SCPU Schematics
Replies: 5
Views: 2287

S-SCPU Schematics

I have started the reverse engineering of the SNES CPU. Most gates have been identified and portions of the chips have been converted to schematics. Some registers and functions have been tidied up but some are a bit scattered at the moment but this is still is work in progress. The DMA section look...
by regiscaelus
Thu Jan 19, 2023 8:34 am
Forum: SNESdev
Topic: CRT monitor vs. CRT TV (also SNES region modding)
Replies: 25
Views: 1954

Re: Two Ship mode 5 hires + interlaced comparison

A lot of people (myself included) like to use a PVM rather than a TV for this purpose. They're normally multi-sync for NTSC and PAL, have lots of tuning options, multiple inputs, and often RGB. They also tend to have a convenient cube shape. Otherwise old TVs are more common and cheaper, especially...
by regiscaelus
Thu Jan 19, 2023 1:48 am
Forum: SNESdev
Topic: CRT monitor vs. CRT TV (also SNES region modding)
Replies: 25
Views: 1954

Re: Two Ship mode 5 hires + interlaced comparison

Thank you @linariq. It looks like I need to find a CRT monitor, then. Note that CRT monitors and CRT TVs are completely different, so ideally, you'd want a CRT TV (if you already have a real console) to test real 15 kHz interlacing. Yes, this is actually what I meant; a CRT TV like in the olden day...