Re: SSC DIP Switches

[dempson@actrix.gen.nz (David Empson)]

Simon Biber <simon@basilisk2.cjb.net> wrote:

> I've got my SSC set up now with a null-modem to the PC. I've successfully
> used ADT to transfer some comms programs across. I now have AGATE and ZLink.
> 
> Now the problem is that these comms programs insist on having the interrupts
> turned on (switches 2-6 and 2-7 ON) but ADT requires them off.

Switch 2-7 isn't related to interrupts.  It determines the pin number
from which the Clear to Send signal is derived.  It must be OFF if the
jumper block is in the TERMINAL (printer) position, and should nearly
always be off for the MODEM position.

Switch 2-6 enables interrupts in the ON position.  This is required for
communication software, and is usually disallowed for other software
(particularly printing).

Unfortunately there isn't much you can do about it if you regularly run
two pieces of software, one of which uses interrupts and the other of
which doesn't.  The computer will crash if the serial port is used with
interrupts enabled, if the program doesn't provide an interrupt handler.

The best solution might be to install another Super Serial Card, and set
each program to use the correctly configured card.

It might be possible to enable interrupts on the card but avoid them
occurring.  This requires having nothing connected to the DSR and DCD
inputs when the card is used with the non-interrupt software (ADT in
this case), AND to ensure that connectors are removed or attached only
while running communications software.

These pins cause an interrupt whenever they change state.  The other
interrupt sources (transmit and receive complete) have software enables,
so they wouldn't occur unless the software enabled them.

 It's a pain
> and a hassle to move the drives and monitor out of the way to remove the
> case and change the switches each time..
> 
> Is there a better way?
> 
> Simon.
> 
> PS: With IN#2 and PR#2 I have nice remote access to Applesoft.