Re: What is the most used ROM in the brown 1541?

From: Spiro Trikaliotis <*ml-cbmhackers_at_trikaliotis.net*> Date: Fri, 19 Jun 2015 22:19:32 +0200 Message-ID: <20150619201932.GB32395@hermes.local.trikaliotis.net> · ml-cbmhackers_at_trikaliotis.net

Hello Julian,

* On Fri, Jun 19, 2015 at 10:10:48AM +1000 Julian Perry wrote:

> Incompatibility at power up when other devices were present on the IEC
> buss.

In fact, I always had a C64, a 1541 and a MPS801 on the bus. The MPS was
almost always switched off. However, I have never seen this behaviour
you describe.

> From memory code up to -03 looked for a handshaking line held low at
> POST (?CLK?), and if so fired off the disk bootstrap routine.

The code at $E780 checks for CLOCK and DATA. Both have to be LOW in
order to activate the autostart feature (cf.
http://cbmrom.trikaliotis.net/listings/1541-03.lst, search for the label
"CheckAutostart:" or "00E780", without the quotation marks).

Regards,
Spiro.

-- 
Spiro R. Trikaliotis
http://www.trikaliotis.net/

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