2 ADC0838 and a Basic Stamp

G McMurry

I would like to make a 16 channel A to D converter using 2 ADC0838s and a single Basic Stamp. I am running out of pins on the stamp...

I have used the ADC0834 before so I am familiar with the code I need. My interest now, is to use the least number of lines (pins) to connect the two ADC0834s to the Stamp.

I figure I can tie all of the data lines together -- Only one of them is used at a time. I also assume I do not need /SE or SARS. I also think that the CLK can be common.

So I am planning on 4 lines.

Data In/Out
Clock
Chip Select #1
Chip Select #2

I might want to pull up the /SE lines, though I probably do not need to bother.

I am going straight to PCB so any help I can get from this forum would be appreciated.

Here is my anticipated schematic.

I always appreciate all comments.

Greg

Sapphire

I would put two 4k7 resistors on the Data line, one for each ADC just in case both of the /CS lines go low due to a program bug. Otherwise the ADCs might both output at the same time and short their Dout pins. I would also pull-up the /CS lines to ensure they are high during reset or programming. And P14 should be /CS-2.

G McMurry

Great ideas!

I will include them in my design. I guess if I pull up the /CS lines, there should be no other collisions, but adding a resistor to the DI/DO lines is easy.

Thanks for you input.

Greg

Updated Schematic: