On Mon, 11 Dec 2006, Peter TB Brett wrote:
Hi folks, Slightly off-topic, but I need some suggestions: I'm currently building an ADC board to go with an existing microprocessor board I have available. It's going to have eight 100 kHz 12-bit serial ADCs. Now, the problem I have is that I want to read from all eight channels simultaneously and at regular intervals, but I have no control over how often or regularly the microprocessor will request data.
My thoughts, for better or worse: Use a SAR A/D, which allows you to trigger all A/Ds at once using a TRIG line. (The usual sigma-delta A/D is free-running, so it just gives you the value most recently read, which can lead to read-skew.) The A/Ds will then hold the values you want indefinately in their internal regs. Then get rid of the CPLD entirely, and use the PIC to do all the bit-banging necessary to transfer the data out of the A/Ds and to the host uProcessor. Stuart _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
