floobydust wrote:
I've been through the SymonIII code extensively and made a lot of modifications to it initially. The default ISR handler in SymonIII processes a null character as a program break, so any binary transfer wont pass the character receive routine.
Huh, didn't notice that. Perhaps that's why the download routine is handling ASCII hex and not binary files.
floobydust wrote:
I've since written a complete BIOS for the 6551 and 6522 with an ISR that handles the 6551 and both timers of the 6522. It also handles the BRK opcode and a null character. I added an Xmodem flag to the BIOS so it will accept all characters into the buffer which is a requirement for any binary transfer routine. The Xmodem loader uses this flag when receiving a block from the terminal program.
Well, to write my own BIOS is a long term goal. Right now I'm learning how program the chips and getting something out from them. The bin to ASCII hex program I wrote seems to work just fine so every time I assemble the makefile will also produce the ASCII hex file.
But right now I'm battling 65C22 IRQ's
(or rather I'm learning how they work).