| Re: [hatari-devel] New SCC 85C30 support for MegaSTE/TT/Falcon |
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Le 14/09/2023 à 19:29, Eero Tamminen a écrit :
Hi,
On 4.9.2023 23.45, Nicolas Pomarède wrote:
over the latest months I spent some time (slowly) rewriting SCC 85C30
emulation in Hatari.
This chip is used in MegaSTE / TT / Falcon as a high speed serial
interface but also as a LAN interface.
It's a rather complex chip with 2 channels (each one can drive a
physical interface), with *lots* of registers to program it and a huge
doc (nearly 400 pages), so it was quite some work to understand its
inner working and emulate as much as possible for Hatari.
Looking at SCC related regs in this:
https://ftp.lip6.fr/pub/atari/Docs/hardware.txt
They seem to differ between all the related machines (MSTE, TT and
Falcon). Does code take that already into account?
Hi
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 ?)
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 ?
...
It's quite possible I broke some things when rewriting SCC code, but
just booting Freemint is already using channels A and B interrupt as
well as many registers so hopefully there should not be too many
things to fix :)
Does someone know some programs that will use the SCC for serial
transfer ? If so, does it still work ?
When serial transfer is confirmed to work, we can add support for more
physical interfaces, as they were used on MegaSTE / TT /Falcon
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 ?
Nicolas