XMODEM code for CP/M on the Z180. This code is work in progress and has bugs.
Only looking at the code starting at line 325 where XMODEM reception starts...
Using "terminal 1" for main communication with "UART0" to issue CP/M commands and do XMODEM data transfer, and "terminal 2" to only receive debug data from "UART1" sent by instructions placed in the code to observe various parameters.
After setting the code to receive XMODEM data and "terminal 1 to send a text file using XMODEM the SC126 sends the 'C' character and "terminal 1" sends the SOH.
This is confirmed by debug code sending the received "SOH" byte to "terminal 2"
The code up until line 424 works correctly
After this where the inline assembler code starts to receiv the packet data it fails.
The assembler code points (HL) registers at memory 0x9001 for storing packet data. The B register is set so that it will read in 134 bytes of packet data.
The code checks the UART0 status register to see if the RX buffer is empty and reads in a byte from the UART data register when ready.
The code checks for an over-run error by reading "ASCI Control register EFR bit 3" and jumps to "error:" and executes a HALT instruction if over-run occurs.
(I have an LED connected to my CPU HALT line).
The code never makes it past receiving the first byte of data and always jumps to the over-run "error:" condition.
I can not explain why this is not working because the assembler code should be more than fast enough to keep up with reception at 115200 baud and I previusly made an Arduino project in 'C' and it works perfectly without issues.
If anyone is reading this and wants to try this on their SC126 CP/M setup please feel free to do so.