I have an existing ecm running on a MC68HC912B32. While it is running I can put it in a mode to accept a flash routine through J1850. I'm at the point where I need to implement the flash routine to send to it. The flash routine gets uploaded to RAM at 0x80-0x3e0. The stack is at 0x400 and I have 0x0-0x80 to use as a data area. The registers are at 0x1000. I'd like to write the routine in C (is that even possible?) and compile it to S19 or a bin file that I can then upload to the ecm.
My problem is I don't know which tools to use and how to tell those tools the setup. Any suggestions on how to get started? I've looked at Syn + gcc and the free CodeWarrior, but like I said, I don't know how to set it all up to do what I need.