Re: [hatari-devel] New SCC 85C30 support for MegaSTE/TT/Falcon

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

On 14.9.2023 23.50, Nicolas Pomarède wrote:
> they don't differ that much. They all have in common the regs 
> FF8C81/83/85/87 and the TT has some extra regs :
>
>   - a bit to switch port A between 1 RS422 LAN port (MiniDIN, 8 pins) 
> and 1 RS232C serial port A (DB-9P, 9 pins). Not supported yet
>
>   - some regs at FF8C01-FF8C15 to handle dma transfer with SCC. Not 
> supported yet. Are there some TT programs that make use of this ? 
> (Emutos maybe ?)

EmuTOS detects SCC:
https://github.com/emutos/emutos/blob/master/bios/machine.c#L182

And seems to support SCC serial:
https://github.com/emutos/emutos/blob/master/bios/serport.c#L480


> Also not emulated yet is to connect TT's MFP timer C as an external 
> clock for the SCC.
>
> As you often use/work with linux for Atari, do you know if it uses SCC ?

Hatari's partial SCC support has been enough to boot Linux on Falcon, 
but on TT it would require VME SCU support, that is still missing from 
Hatari.

As you can see from this:
https://github.com/torvalds/linux/blob/master/arch/m68k/kernel/head.S#L2744

Both Atari & Mac have SCC, and I think Mac has same version as Atari:
https://en.wikipedia.org/wiki/Zilog_SCC

Atari code:
https://github.com/torvalds/linux/blob/master/arch/m68k/atari/ataints.c
https://github.com/torvalds/linux/blob/master/arch/m68k/atari/config.c#L85
https://github.com/torvalds/linux/blob/master/arch/m68k/atari/debug.c#L52

I assume Mac SCC access code to be here:
https://github.com/torvalds/linux/blob/master/arch/m68k/mac/


> > Once you have that, I could help in adding the CLI options and 
> > updating the docs accordingly.
>
> good :)
>
> > I'm not sure where to fit SCC options in SDL GUI though, "Devices" 
> > dialog is pretty full...
>
> yes, it's rather crowded :) Maybe add some intermediate options' screen ?

You mean separate "Serial config" dialog invoked from the Devices dialog?


	- Eero