Re: Run of Dual CF-Card/Hard Disk IDE S-100 Boards

Hi Thomas,

Drive selection is achieved using a D Type flip flop (U16A) where the data input is data line DO0, this data line is clocked into the flip flop through the combined SEL_SECOND* and WR* signals thorough NOR gate U15A. you need to be looking in this area with a logic probe/ logic analyser to see if the pulses are generated when you address the port.

One other possibilty which springs to mind is , Have you jumpered K1 (reset jumper) or is it floating. U16A uses the reset line to initialise the flip flop output Q (pin 5) to low and thus illuminating D18 (CF-A SELECT).

Please make sure you are using the schematic dated 23/3/2014

regards

David Fry
On Tuesday, March 18, 2014 10:27:41 PM UTC, Edward Snider wrote:

Hi everybody,

I'd like to do a board distribution project of Dual CF-Card/Hard Disk IDE S-100 Boards.

Is anyone interested in getting one or more of these?

Just post here and I'll get a list started.

Thanks,

Ed