SPI Serial Bus Question

skynugget

Hi all,
I have a project that has a few IC/s on a 3 wire serial bus. (ds1302/ds1620/tlc549).
Id like to ad the max1270 ADC to my project, wich is a 4 wire serial device.

can i share the clock/dataio bus from the 3 wire serial bus for the max 1270 and save myself some pins? my plan is to try to get away with taking up a pin for the max1270 chipselect, and a pin for the other max1270 data pin.


thanks in advance!

Chris Savage

Hello,

Yes, you can do this. SPI device can almost always chare the clock/data lines. Usually you need only an individual chip select line. When a device has separate DI/DO lines, you can usually connect them via a resistor from the DO line to the bus. So DO would connect through the resistor (say 1K) to the bus whereas DI would connect directly.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support

skynugget

thanks for the quick conformation chris, someday i hope to help you out!