LTC1298 AD chip SX assembly language troubles

Randy Harris

I am trying to get the LTC1298 chip to work with the SX assembler but I cannot get the 1298 to reply back with the conversion data. What am I missing. I think I have read the spec sheets correctly. Do I have to use the pull-up resistor for the port bit inputting the data from the 1298? It does not seem to matter if I pull it up or not I get no data from the 1298. I have included the test program in an attachement.

Thanks for any help.

Jamesx

I've had luck getting that and similar chips to talk back, but it can be troublesome sometimes. Important aspects include careful exacting scrutiny of the ADC's datasheet, and getting the clock pulses (to the ADC) tightly organized in your mind and code.

Randy Harris

Yes, I have tried to do it as best I can figure out from the spec sheet.· I feel confident I have it wired up correctly.· I just cannot get it to talk back to me.· I have tried putting a zero data bit before sending the start bit.· I have tried seperating the input and output pins from the chip instead of tying them together with a 1K resistor.· I have tried pulling up the line on the SX that I am reading the data from the 1298 but so far nothing seems to work.· Any other suggestions?

David B

Nice looking piece of code.

It looks like you're not clearing (with setb) the CS at the end of the convert.

Both start and end issue clrb on CS.

David

Randy Harris

Thanks David
I had two mistakes. I commented out the clrb (actually it was a setb, I think). Then I needed to clrb at the end. It works now. Thanks all who helped.