tac@sei.cmu.edu (Timothy Coddington) (09/23/88)
I'm going to implement a 32 bit interface using two Motorola MC68230 parallel Interface and Timer (PI/T) chips. Since I've never programmed this chip before, I'd like to get some recommendations, and/or advice on how to initialize and interface it. The two PI/T chips are designed into a VME parallel interface board (Mizar MZ8305), so the external logic is already designed. I just need to program, it and make the cables. Here is a run down on what I want to achieve: Use one of the programmable protocol modes, and not have to toggle lines through a register. Use one of the interlocking protocols, probably the 16 bit Unidirectional mode. Have the transmission and reception of the 4 bytes be done in an atomic operation. Unfortunately, the registers are mapped to odd addresses on the VME bus and can't be access in 16 or 32 bit chunks (I've seen this done on a few VME device modules, why?). Use the H1, H2, H3, H4 lines. Have a symmetric protocol on both sides of the interface. I'll have the same interface board on each end of the interface cable. One interrupt per 32 bit transmission/reception. I feel comfortable with what I've read, and have thought to implement initially, but I may have misunderstood something from the manual and I'd like to save some time. How do you recommend I initialize the various control registers, write and read the 32 bit values, and connect the different handshake signals, etc? What are some of the known/unknown gotcha's for this chip? Additional info: I'm using a 68020 single board computer to control the interface (Motorola MVME133A-20, 20MHz). I would appreciate any input. I'd to talk to someone who knows this chip well, because I have some questions. Thanks in advance. Tim Coddington Software Engineering Institute Carnegie-Mellon University (412)268-7712, or (412)244-8557 *ANY* time Arpanet: tac@sei.cmu.edu