cdj@psueclb.BITNET (09/25/88)
Hi there... About the AppleTalk on ST issue, I second the motion of the DMA interface. Trying to *write* data to the cartridge port is the kind of thing that sends developers screaming into the night. I am doing it with my senior EE development lab project, a Computer-Controlled Logic Analyzer. In order to control the thing, you use memory locations (READ ONLY) as 'switches'. If you had to write real data, you would probably have to read from a switch, then write to a dummy location in RAM, having the cartridge system take the next 16 bits on the data lines as ITS data as well. That means two memory accesses for each write, plus the data-line/valid data synchronization nightmare. You know, I sure with I had the resources to replace the MMU chip with a similar one that *would* allow writes to the cartridge port. As it is now, what's a hacker to do? ;-) Christopher D. Johnson Penn State University Electrical Engineering Undergrad cdj@psuecl.BITNET