lear@unga.ece.utexas.edu (Jim Lear) (06/17/89)
I have a very nice 8 bit "flash" A/D converter (25 Mega Samples per sec) and it would be nice to attach it to the parallel port and use it (along with the proper interface circuitry and preamplification) and the amiga as a cheap 2 trace digital oscilliscope. However, I'm not sure what the best way to read the data from the parallel port is. I'm a complete novice in a multitasking environment and the thought of using the parallel.device is frightening as well as nausiating when considering speed. I would prefer to deal with the hardware in assembly language, outside of the multitasking OS domain (since this will not be distributed, I can insure that no tasks will be competing for the parallel port). Scanning through the wonderfully complete and rigorously detailed Adisson Wesley Hardware Man. I am left somewhat less than sated. Firstly, the SEL (or BUSY or POUT) line could be useful for indicating which channel (trace) is being transmitted. Can the SEL (or others) simply be read from CIAB PRA? Secondly, will there be any trouble if the interupt control register is polled? Since polling clears all the interupt flags in the ICR that might be occurring, could polling foul up the event counters and timers? If polling is impossible (may God please permit polling for speed sake) is it possible to easily vector the 8520 interupt through my handling routine before the OS gets its filthy slow hands on it? Or perhaps it might be possible to ignore (mask) any interupts on CIAA if they are not critical? (oh please let there be polling). Thirdly, any predictions on max. tranfer rate? Finally, any suggestions or information from you experience folk would be greatly appreciated. Jim Lear I've touched my toe to the water and the water is cold.