Contemporany 6502 compatible hardware (chips, actually).

[tokafondo]

Hello. As you may be aware, I'm designing my own 65xx computer. But nodaways, it's difficult to get companion chips for graphics and sound, making eberybody going legacy hardware or FPGA to get something shown or played by it.

So... I would like to start here a list of contemporany hardware, ready to be used in your 65xx computer design with no more logic than the classic computers had, or at least the minimal one. Additions and corrections are welcome.

• GRAPHICS
  • EPSON chips. There are several ones with included dedicated VRAM, that can be addressed directly or indirectly. Look for them here.
  • VLSI SOLUTION. There are 1Mbit and 4Mbit SRAM chips that includes a video generator circuit that creates a image from the data stored in the memory. They can be used through SPI (that would require external logic and careful timing) and 8 bit parallel bus. The 8 bit access has a caveat: it can only be done in sequential read and write, in 4 byte blocks (*).
  • FTDI/Bridgetek. See MULTI-FUNCTION chips section.
• SOUND
  • YAMAHA YMF807 and YMF825. Both have a 16 channel FM synthetizer, but the 807 also includes 8bitPCM / 4bitADPCM stream playback and a hardware sequencer. The only caveat is that they are controlled by a serial bus, instead of a 65xx style bus. (PLEASE SEE NOTE BELOW)
  • FTDI/Bridgetek. See MULTI-FUNCTION chips section.
• MEMORY
  Look for x8 variations, as they have a 8 bit wide data bus. 16 bit ones require extra logic and not a single 65xx compatible chip can directly manage a 16 bit data bus.
  • ALLIANCE
    • SRAM memory chips. The list is here.
    • FLASH ROM chips. The list is here. These models from Alliance can be erased and reprogrammed partially inside the computer, so they can act as internal storage, allowing uprading things like the kernel, the charset, or even to install software that would be always available at powering the computer.
  • IDT/RENESAS
    • SRAM memory chips. Look for them here. There are several very fast ones.
    • Dual-port SRAM chip chips. To be found here.
  • ISSI
    • SRAM chip list, here.
  • Infineon/CYPRESS
    • SRAM chips. Search for them in the Products tab, and then in the Find Parts button.
    • Dual port SRAM chips. Look for datasheets of × 8 Dual-port Static RAM models.
    • nvSRAM chips. Actually, SRAM with an integrated flash array that will backup the contents of the SRAM array when powered off, and restore it when powered on. Search for them in the Products tab, and then in the Find Parts button.
  • Microchip
    • Parallel EEPROMs. They are all 8 bit wide data chips.
    • Parallel NOR Flash chips, formerly Silicon Storage Technologies (SST) products. Filter by x 8 in the Organization column, somewhat hidden, scrolling to the right.
  • Maxim
    • nvSRAM chips. Actually, SRAM with an integrated lithium battery that will keep the SRAM array powered, when external power gets off.
  • ST Microelectronics
    • NVRAM chips. Also, an internal battery will keep the data when the external power goes off.
• COMMUNICATIONS
  • Maxlinear/EXAR.
    There are a variety of communication chips to choose from from this manufacturer. Please, set the filter in the left column the Data bus interface to Motorola, and watch out for 16 bit offerings. Still, you will find some surprising chips there.
  • Texas Instruments.
    TI has currently the TL28L92 and TL16C750E UART chips, for high speed serial transfers.
  • NXP.
    NXP has several chip offerings, seen here, that could help the 65xx family to talk to modern serial interfaces like SPI and I2C.
• MULTI-FUNCTION
  • FTDI/Bridgetek. The FT80x chips provide graphics generation, sound synthesis, audio wave playing and touch screen controlling. They are controlled by I2C or SPI bus, though, so additional logic is needed.

NOTE ABOUT YAMAHA SOUND CHIPS:
I actually asked YAMAHA about these sound chips and about getting the programming manuals. This is their answer:

Code: Select all

Dear Claudio Sanchez,

Thank you for your inquiry.
We regret to say that our IC products cannot be traded with individual customers. Therefore, we cannot provide data sheets.
Thank you for your understanding.

Sincerely yours,

Yamaha Corporation
Customer Support Team

EDIT: Fixed a typo.
EDIT: Added VLSI chips and expanded some info.
EDIT: corrected Alliance Flash Rom list and added ISSI memory chips, IDT/Renesas dual-port SRAM chips.
EDIT: Added Infineon/CYPRESS memory chips.
EDIT: Added Microchop, Maxim and ST Microelectronics memory chips.
EDIT: Added FTDI/Bridgetek chips.
EDIT: Added Maxlinear/EXAR chips.
EDIT: Added Texas Instruments chips.
EDIT: Added NXP chips.
EDIT: Added note about Yamaha sound chips.

[tokafondo]

[reserved]

[BigEd]

I'd add propeller, as a video-capable chip.

And these:
1 Mbit Versatile SPI / 8-Bit Parallel Bus SRAM with Video Display Controller

[tokafondo]

BigEd wrote:

I'd add propeller, as a video-capable chip.

Well, in that case, any chip that could act emulating functions, could be added: FPGAs, CPLDs, Arduino, Raspberry... Yes, they work, but are they part of the simple spirit?

[BigEd]

Everyone will have their own idea of what counts as simple enough! The propeller is a 40 pin DIP, and yes, it's entirely built around simple CPUs bit-banging protocols, with a modicum of hardware support to make video output straightforward. It might well not meet your personal list of simple solutions.

[tokafondo]

Well... For me, definition of "simple" is "whatever the chip does by itself", instead of "the chip is emulating a function that hasn't been designed for"... But of course, the propeller is a chip designed to be programmed to do "different things as needed by the user", instead of "a chip that does whatever: graphics, sound, a serial or parallel communications, read a keyboard matrix and output a value from it, an ADC that reads from analog joysticks or paddles...".

"Not simple" is Arduino or PIC or Raspberry emulating a SID or a video chip, because you should then program that chip or system to emulate the chip you want.

Up to this point, however...

Maybe today's "simple" has nothing to do with '90-'00s "simple" or '80-'90s "simple".

Should I then add all the myriad of MCUs, SBCs or FPGAs that emulate chips?

[LeoN]

Link to the list of ALLIANCE Flash ROM chips is invalid.

ISSI SRAM chip list - http://www.issi.com/US/product-asynchronous-sram.shtml.

IDT dual-port SRAM chip list - https://www.idt.com/eu/en/products/memory-logic/multi-port-memory/asynchronous-dual-port-rams. Available at reasonably affordable prices.

[BigEd]

Sorry, I may have introduced unwanted extra thoughts. What you're after, I think, is to exclude user-programmable and field-programmable chips, and that's reasonable enough. By extension, you'd exclude modules which made use of those. And that's fine, as a preference which may well be fairly widely shared.

It might be useful to link to other threads which do include those other kinds of solutions, if they exist. I feel like we've had numerous threads about how to do video, or how to add a display - here's a simple search. But I'm not sure of the same for sound.

[Chromatix]

There are some FIFO chips that are reasonably inexpensive, and allow the input and output ends to be asynchronous to each other. Attach one end to the data bus (and have reads reflect the fill status lines), and the other to an octal latch and a flash DAC, with a clock-out rate of whatever you like. Wire the clock line up to a timer output from a 6522 VIA if that's convenient, and you can vary the sample rate. Instant sampled sound output.

It shouldn't be especially difficult to build the waveform generators from the SID in discrete logic, either. You'll probably want a 12-bit DAC for the waveform itself and an 8-bit multiplying DAC for volume control. That's a more ambitious project, triply so if you try to include the filter section as well.

[tokafondo]

LeoN wrote:

Link to the list of ALLIANCE Flash ROM chips is invalid.

Corrected. Thanks!

LeoN wrote:

ISSI SRAM chip list - http://www.issi.com/US/product-asynchronous-sram.shtml.

IDT dual-port SRAM chip list - https://www.idt.com/eu/en/products/memory-logic/multi-port-memory/asynchronous-dual-port-rams. Available at reasonably affordable prices.

Added!!

[tokafondo]

Chromatix wrote:

There are some FIFO chips that are reasonably inexpensive, and allow the input and output ends to be asynchronous to each other. Attach one end to the data bus (and have reads reflect the fill status lines), and the other to an octal latch and a flash DAC, with a clock-out rate of whatever you like. Wire the clock line up to a timer output from a 6522 VIA if that's convenient, and you can vary the sample rate. Instant sampled sound output.

It shouldn't be especially difficult to build the waveform generators from the SID in discrete logic, either. You'll probably want a 12-bit DAC for the waveform itself and an 8-bit multiplying DAC for volume control. That's a more ambitious project, triply so if you try to include the filter section as well.

So that would be a circuit or a project for a FPGA or CPLD, wouldn't it?

[tokafondo]

BigEd wrote:

Sorry, I may have introduced unwanted extra thoughts. What you're after, I think, is to exclude user-programmable and field-programmable chips, and that's reasonable enough. By extension, you'd exclude modules which made use of those. And that's fine, as a preference which may well be fairly widely shared.

It might be useful to link to other threads which do include those other kinds of solutions, if they exist. I feel like we've had numerous threads about how to do video, or how to add a display - here's a simple search. But I'm not sure of the same for sound.

Well... Maybe "Contemporany 6502 compatible hardware" does not clearly state that I was trying to create a list of discrete chips, instead of programmable things or circuits. I will add something to the title to make it clear.

I'd like this to be a reference for people that wants a fast and easy way to get chips for their projects: read the datasheet, wire the thing and here you go. The original IBM PC was created that way!! What made the difference was the BIOS. The rest were all off-the-shelf hardware.

[rpiguy2]

tokafondo wrote:

BigEd wrote:

I'd add propeller, as a video-capable chip.

Well, in that case, any chip that could act emulating functions, could be added: FPGAs, CPLDs, Arduino, Raspberry... Yes, they work, but are they part of the simple spirit?

Technically the Propeller was designed from the outset to provide display output and includes a bitmap font and shift registers for banging out pixels. It is just a VERY programmable one. The fact it comes in a 40 pin DIP makes it feel more period-correct than an LCD controller with a ton of features onboard that will mostly go unused.

[tokafondo]

rpiguy2 wrote:

Technically the Propeller was designed from the outset to provide display output and includes a bitmap font and shift registers for banging out pixels. It is just a VERY programmable one.

I've been studying the propeller datasheet and for me, this is a chip that you could program to act as a video output device, and you could also program it to provide math functions that would compare it to a math co-processor to like the 80287 and 80387 were. I mean... does it provide the video function "as is"? With no program or rom? It does include a charset and does really help, but I still see it as a "general purpose", programmable SoC than a video chip, or math chip, or something else. It can replace a chip, but it's not the chip itself.

Designers should be then both programming the propeller as much as the 6502 itself... or getting a ROM for the propeller to act as the video chip for the '02. But hey! It could also act as a sound chip, wouldn't it? With a max clock of 80mhz, software MIDI or even SID emulation could be done with it.

I think I'm not including it in the list. And that doesn't mean it's not a valid choice, of course.

Thanks for your suggestion anyway.

rpiguy2 wrote:

The fact it comes in a 40 pin DIP makes it feel more period-correct than an LCD controller with a ton of features onboard that will mostly go unused.

Well... I'm spanish. And maybe I chose the wrong word here. I used "contemporany" referring to chips available "nodaways", instead of "chips contemporany to the 6502". Chips that could be bought these days because they are still in production or at least not marked as "obsolete". EPSON does have some chips that are still in production but they are being phased out, "not recommended for new designs". That ones are right for me.

But the myriad of chips that came in computers in the 80's-90's, that you can buy as used, extracted from computers, or even some of them "new old stock", shouldn't fall in the category of "contemporany". Yes, I can get the 6502 to work with the chip of "whatever console or computer" from the 80's, and build a computer around it. But that chip wouldn't be "contemporany", while clearly the 6502 itself still is.

[BigEd]

(I would recommend a new thread on the possibilities of the propeller as a (multi-purpose) peripheral)