[net.micro.mac] Configuring the SCC chip on the Mac

rajiv@ur-helheim.UUCP (Rajiv Arora) (06/03/86)

Hi,
    I'm engaged in some research in networking and I need to use the
Mac as an experimental node. My problem is that I have to reconfigure
the Zilog 8530 SCC chip that controls the printer and modem ports. Here
are some questions I have, which I would appreciate answers to:
	1) How many SCC chips are there in the Mac? Does one chip
	handle the printer and modem ports AND the mouse?

	2) Are the physical addresses of the various registers on the
	chip documented anywhere? Indeed, is there ANY documentation
	that will ease my task?!

	3) If any of you have attempted/succeeded in programming the
	beast and know it's quirks, I'd be grateful for any
	information. IM doesn't seem to be much help, as this is
	pretty low level assembler stuff.

Again, any info would be greatly appreciated.
-- 
						       Rajiv Arora
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maclab@reed.UUCP (Mac DLab) (06/05/86)

> 
> Hi,
>     I'm engaged in some research in networking and I need to use the
> Mac as an experimental node. My problem is that I have to reconfigure
> the Zilog 8530 SCC chip that controls the printer and modem ports.
> 						       Rajiv Arora

For a good introduction to programming the SCC (including simple,
readable, modula-2 code that really works!) you can't beat Jeff
Mitchell's article in MacTutor Vol.2 No.1 January 1986 ("Direct Serial
Port Access").


Scott Gillespie

ephraim@wang.UUCP (pri=8 Ephraim Vishniac x76659 ms1459) (06/05/86)

>     I'm engaged in some research in networking and I need to use the
> Mac as an experimental node. My problem is that I have to reconfigure
> the Zilog 8530 SCC chip that controls the printer and modem ports. Here
> are some questions I have, which I would appreciate answers to:
> 	1) How many SCC chips are there in the Mac? Does one chip
> 	handle the printer and modem ports AND the mouse?
> 
> 	2) Are the physical addresses of the various registers on the
> 	chip documented anywhere? Indeed, is there ANY documentation
> 	that will ease my task?!
> 
The use of the SCC chip in the Mac is reasonably well documented (addresses,
interrupt vectors, and all) in the Hardware chapter of Inside Mac.  This
chapter was first published as part of one of the software supplements and
also appears in the bookstore edition.  It was not in the "Phone Book"
edition.  I *think* Hardware is in volume three, but check the index.

Ephraim Vishniac
decvax!wanginst!wang!ephraim

phil@sivax.UUCP (06/05/86)

> 
> Hi,
>     I'm engaged in some research in networking and I need to use the
> Mac as an experimental node. My problem is that I have to reconfigure
> the Zilog 8530 SCC chip that controls the printer and modem ports. Here
> are some questions I have, which I would appreciate answers to:
> 	1) How many SCC chips are there in the Mac? Does one chip
> 	handle the printer and modem ports AND the mouse?
> 
> 	2) Are the physical addresses of the various registers on the
> 	chip documented anywhere? Indeed, is there ANY documentation
> 	that will ease my task?!
> 
> 	3) If any of you have attempted/succeeded in programming the
> 	beast and know it's quirks, I'd be grateful for any
> 	information. IM doesn't seem to be much help, as this is
> 	pretty low level assembler stuff.

Yes, I have proigrammed the SCC chips,  we connect a CDROM drive to it at
700K baude external clock.  There is only 1 SCC 8530 chip.  Yes, the mouse
interrupts come in on the chip, causing lots of problems.   The stuff needed
to program the chip is documented in the SYSEQU.TXT file with the MDS system.

There are 2 or 3 equates that let you 'talk' directly to the chip,
ADATA,ACTL,BDATA,BCTL, SCCrd,SCCwrite,  No there is no real docs on how to do
it.  The only real quirk I found about the chip is the 2.2 microsecond wait
between commands sent to the chip.  It requires this delay, which I handle with
a   MOVE.L (SP),(SP)  instruction as a slow NOP.

Any other questions, send me mail

Phil Hunt

Calma!sivax!phil


>