This is probably outside the scope of your problem (if you don't want any kind of external chip programmer), but one of the ideas I came across is to use a CPLD as a boot ROM. I wrote one up in Verilog but never tested the hardware. It's workable even in the smallest 32 macrocell CPLDs, as it mostly ...

One little fun fact about the SNES CPU, the speed is often quoted as 3.58Mhz, however that is the maximum speed. It also can run at 2.68Mhz, and most SNES games were released on cartridges where the cheaper ROMs only supported 2.68Mhz. Like BDD mentioned, it slows down to 1.79Mhz during port access ...

Still looking for input?

In addition to 74LVC, some other 5V-tolerant families are VHC, AHC, LCX, and LVT.

If you need 5V outputs, there are '8T' parts like 74LVC8T245. It's a '245 but with dual power supplies, so you can output 5V on one side.

There is a type of bidirectional level translator ...

Vinculum 2 from FTDI looks pretty good for USB also. It's 2 USB host ports, and it's about half the price of that Cypress one.

PIC32 looks really nice, and is what I'll be using for peripherals in my next design. They upgraded the parallel port from the older PICs, now it has a 4-byte FIFO (or can ...

That is quite a cool idea to push the system a little further, I like it.

Too bad on the platform I use (NES), I don't have access to a sync signal, or I'd try to fit it into my crazy future expansion design.

It's not completely transparent, but surely close enough. I've seen a lot of NMI/IRQ ...

I've wrote a sound synth that runs on an 18F PIC on my NES cartridge. Pretty much how kc5tja is saying.

I've got waveforms in RAM (which can be gradually modified to do SID-like effects such as pulse-width modulation, or pre-set to any kind of waveform). Use fixed-point to get the sound frequency ...

Here's the code I wrote for use with AM29F040, let me know if it's any good for the chip you're using.


byte_program:
stx temp2
ldx #$AA
stx $8555
ldx #$55
stx $82AA
ldx #$A0
stx $8555
sta (ptr),y ;(ptr),y
sta temp_lo

@program_wait:
lda (ptr),y
sta count_lo
lda (ptr),y
sta count_hi ...

I doubt mp3 or ogg would be any good for 6502, but I'd be happy if someone surprised me. :)

The problem is not the CPU architecture. The problem is clock speed. Even a 68020 at 8MHz will have a very hard time keeping up with Ogg or MP3.


Yeah, I'm always thinking in terms of real-time. For me ...

wav would be really easy. All the samples I play are just plain 8-bit unsigned PCM. You'll want it in an optimal format, converting or decoding it (at high sample rates like 44.1khz) for every sample will take some major CPU time.

If the CPU is supposed to be doing anything else at the same time ...

They're clones of these chips, sounds like the same pinout:
http://nesdev.parodius.com/2A03_pinout.txt
http://nesdev.parodius.com/2A03%20technical%20reference.txt
http://nesdev.parodius.com/nes_ppu.txt
http://nesdev.parodius.com/2C02%20technical%20reference.TXT

Here's a Famicom schematic ...

Also (in the case of the video RAM for the tile map) it gave the cartridge designer some flexibility with less RAM. For the PPU there's 2kB of internal VRAM in a 4kB address space. A full screen uses 1kB. The NES brings an address input to the cart edge, so you can set the screens to be mirrored ...

Ah, there isn't all that much tech info on zophar.net. Try my website:
http://nesdev.parodius.com/
There's a lot there, I don't update as often as I should though. There's a forum too.

If you're gonna use an NES emulator, use Nintendulator (fast PC required). On most emulators it's really easy to ...

I think it's great, even if you treat it like a normal 6502 with 16-bit index regs. The only tricky part for me was switching often between 8 and 16-bit accumulator. With more flexibility comes more ways to make mistakes.

I learned 6502 by running my programs on NES emulators. I can use the real hardware now that I built my own cartridge. :)

If you're willing to learn the quirks of that system (which is mostly related to the graphics), it's a good one to use. NMOS 6502 (no decimal mode though), good sound, decent ...

For an OS, are you all familiar with Contiki? http://www.sics.se/~adam/contiki/
I would try to use it if I was able to compile an NES version with cc65. :?


My idea: most computers I know off have a RS-232 port. We can program the OS so that it treats this particular port as another drive. We ...