View Full Version : RCTIME and COUNT through an Analog Switch
02-19-2010, 11:46 PM
Has anyone been successful expanding the IO pins of a Basic Stamp through an analog switch? I have several voltages I want to monitor using RCTIME and was considering the MAX4617 to expand my Basic Stamp..
02-20-2010, 12:49 AM
Using a MAX4617 should work. You need to respect the voltage limits of the MAX4617.
You may do better with a multi-channel SPI ADC like the MCP3208 because it only needs 3 I/O pins to work with the Stamp (Din and Dout are connected together).
02-20-2010, 01:20 AM
I have already designed a board using an ADC but the conditioning I need for each input started making me look at OpAmps and additional voltages on each channel and that got pretty hungry with board space.
The precision I get with RCTIME is fine for my application...
I see what you are talking about with the voltage limit of the MAX4617. I will see if I can find another device.
Another idea might be just to use the 2p 40 pin version. Then I might have enough IO with out expanding...
02-20-2010, 01:51 AM
The original CMOS family has much wider voltage range. Applicable devices would be the
CD4066, quad analog switch
CD4051, single 8 to 1 analog mux
CD4052, dual 4 to 1 analog mux
CD405, triple 2 to 1 analog mux