I once used the SR to figure out what port a parallel input was on by putting a known pattern on the input port and cycling through all the port numbers and when the pattern matched, outputting the port address to the SR. On an 8080 this required self-modifying code. The reason this was necessary was that there was problem with the switches controlling the input port address. - Eric -----Original Message----- From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com]On Behalf Of Jack Rubin Sent: Saturday, February 08, 2014 9:51 AM To: n8vem...@googlegroups.com Subject: RE: [N8VEM-S100:2368] Switch Register Some other front panel uses – Memory sizing, memory testing – writing known patterns to memory and reading them back (or not) Peripheral/UART testing – reading/writing control and status registers, terminal i/o BIOS configuration – build BIOS in RAM, jump to warm/cold start address Code verification – single stepping through code loops, etc. Verifying machine state, processor status, interrupt condition, flag status, etc. (depending on your front panel) Obviously, much of this could be done with a ROM monitor as well, assuming that (a) you have a ROM monitor and (b) you can load it into memory. Probably lots more, but that’s a pretty good slice – Jack From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of nbreeden Sent: Saturday, February 08, 2014 11:31 AM To: n8vem...@googlegroups.com Subject: [N8VEM-S100:2368] Switch Register My system is old enough it has a switch register on it's Front Panel - I have a few questions. - It's on port $FF - is this the correct port for the SR - for some reason I remember it being on $FE? - I find it useful for debugging (writing bit patterns to the SR) - Does anyone else use one this way? - Are there other uses for the SR? -Neil -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to n8vem-s100+...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out. ---------------------------------------------------------------------------- ---- No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4259 / Virus Database: 3697/7075 - Release Date: 02/08/14 -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to n8vem-s100+...@googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
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