Re: GARTHWILSON
Re: BigDumbDinosaur


I've used nearly all of the many different features of the '22, but automatic handshaking has not been one of them. The data sheet addresses it though, starting in section 2.2 on page 10.
The way I'm thinking of doing it is, this. This is all with the ...

I don't know which buffers you plan to use, but the circle at the control input suggests you'll have to connect that pin to ground rather than the high voltage in order to enable the buffer.
Ah yes silly mistake :P!

By the way, the CPLD used in this 65SPI project, the Atmel ATF1504 is turning out ...

Re: Dr Jefyll
You're right about running the whole system at 3.3V, it would make the FPGA functional. But unfortunately the EEPROM can only tolerate a main voltage of 4.5V and having just data lines regulated would be too much effort.

Update
Using the 65SPI CPLD design (https://sbc.rictor.org ...

Re: drogon


You might want to look at using a GAL for soaking up a few "glue" chips and address decoding. I use a single 22v10 in my Ruby 6502 and 2 in my '816 board. Being older devices, they run at 5v.
Thats a good idea too! I'll check if 22V10 chips are available, they'd probably be better ...

Re: GARTHWILSON

Thanks for your clarification! I was mixing up sync and aysnc serial protocols thinking its all serial :P


Daryl Rictor's 65SPI IC is a 65-family I/O IC to multiple SPI devices. In 2018, the CPLD he had been using to make version 1 was discontinued, so he migrated the design to ...

Re: gfoot

Thanks, you've made it a lot clearer for me.


I'm not sure about this bit, I've never seen a 6551 used to drive an SD card and would have thought it not a good match. SD is mostly SPI, which has a separate clock line. You can bit-bang it quite easily on a 6522, and it is possible to ...

Re: floobydust


1- The WD65C51 has a known bug with the Xmit bit stuck on in the status register. There are workarounds, but I'd suggest going with a NXP SC28L91/92 UART/DUART instead. It's more programming effort to make it work, but a much better solution.

Yes I read about this in other ...

Hello!
I'm building a mostly simple SBC with the 6502, which I plan to get manufactured into a PCB and assemble myself into a working computer. I've made the schematic by using a few ideas from other people's projects on this forum and also from youtube videos like Ben Eater's and George Foot's ...