An update on my progress so far with the USB port. My previous report was in error. USBGET.ASM was not working. I looked at what went on and as a result I am modifying USBGET as follows:
a. Add 82C55 initialization - the original USBGET assumed that the port was already initialized.
b. Delete use of speech - the original used the SERIAL IO Port B ability to drive the V-Stamp for text to speech generation. I am using Port B for other purposes so I have converted the speech messages to simple console messages.
c. I converted to Z80 opcodes etc.
d. I changed source to work with SLRSystems Z80ASM.COM, my favorite "native" Z80 assembler. This required some subtle changes.
e. I changed the One second delay loop used for time out purposes. I am not sure what CPU speed the code was based on but as I calculated the timing of the original loop when using my 6 MHz, no wait state, CPU the one second timeout was actually 0.24 sec My code includes some comments that shows the number of T-cycles in the loop with enough explanation that others should be able to calculate.
I have not started testing but as soon as I have progress I will report results and post my modified USBGET.Z80.
Rich Leary