Re: Read full 8-bit character from serial port?

["David Wilson" <mcs6502@gmail.com>]

Ron Kneusel wrote:
> I'm using an Apple IIgs to read/write characters while debugging a
> program on my PC.  I can send a full 8-bit character easily enough but
> my attempts to read a full 8-bit character have failed so far.  The
> high-bit is always set no matter what.
>
> I've tried using IN#2 and the monitor routine at $FD0C.  I've also
> tried using the SSC routine at $C205 with the same result.  For output
> I'm using PR#2 and $FDED which seems to send a full 8-bit character.
>
> So, any ideas on how to read a full 8-bit character from assembly?

I was going to suggest using the Enhanced (aka Pascal 1.1) interface
entry points rather than the Basic (aka BASIC) entry points until I
read the Super Serial Card listing and found that the Pascal Read
routine ANDs the data with #$7F. I am not sure if the IIgs firmware
also does this but would not be surprised if it did. You may have to
drive the Zilog 8530 SCC directly.