SIO for Z800?

[Maury Markowitz]

I was looking over the SIO documentation here:

 

http://spiflash.org/atari/siospecs.pdf

 

Check out page 9. This purports to describe how to use SIO with Zilog Z800 peripherals. Note that several of the pins are changed or moved around.

 

Does anyone know if this was ever used?

[Luigi301]

Are you sure this isn't referring to the Atari Z800 (then Sweet 16, then 1000, then 1200)? The Z800 processor was targeted for 1985 and never released. It also refers to the 800 as the Personal Computer System which would place it much earlier than the mid-80s.

[Rybags]

It'd be Atari's never released Z800. The Zilog was scheduled for release in 1985. Likely that SIO document was made during development of the 800 so probably 1978 or 79.

 

While having a look, noticed the Wikipedia page on Atari SIO isn't very good, makes such notable mistakes as calling SERIN and SEROUT shadow registers when they're not.

 

Atari SIO could probably be made to work with various other system's peripherals though the constraints without extra chip hardware are the 0/5V logic level and fact that the bitstream is always bracketed by start/stop bits, lsb first and 8 bits no parity.

Bitbanging could be used in theory but you lose some flexibility doing it that way.

 

I've been meaning to try and get the Atari to talk to a 1541 but have lack of knowledge of the C= protocols which has been a holdback factor.

[Kyle22]

There's no reason Z80 stuff can*t do SIO. In fact, I ran SIO2CP/M on a TeleVideo system with Z80SIO and CTC chips. I even had UltraSpeed working.

 

I then ran it on a CP/M emulator on an MS-DOS machine and that worked as well.

 

Various Atari compatible peripherals use different families of chips. Even some manufacturers (Rana) changed their chipsets.

 

All you need is a serial port and at least one programmable lo/hi pin for Command.

[Rybags]

So long as either there's hardware IO capable or CPU fast enough to bit-bang then most old systems could probably use SIO devices.

 

Re my project, probably a better starting point might be to get a C64 doing SIO. I already did a 1050 emulator on the ST which was almost all software driven, only used the hardware functionality to derive the 19.2k timing.

[pirx]

also Indus GT and its clones were Z80 driven, no probs, man.

[ClausB]

And the ATR-8000 did SIO, of course.