SPI info

[bleumers_j]

Posted on September 02, 2004 at 03:30

SPI info

[bleumers_j]

Posted on August 23, 2004 at 06:13

Hello,

I'm using an ST72264 to drive 44 SPI switches (ST: L9822E). Communicating with those devices works fine, but i'm looking for practical information about SPI. ST only has an app note for communication with one single EEPROM. Also other manufacturers i've looked at do not have this information. I'm planning to not to daisy chain all 44 of them, but make 4 chains with 11 SPI-devices. The MCU sends 4 independent enable signals, one for each chain. I do this to prevent all 44 devices to stop working when one fails. How long can an SPI connection be? Can i bring the SPI to another PCB without trouble? Can anybody help me find an appnote or give advice. Greets!!!

[alok2]

Posted on September 02, 2004 at 03:30

for making a transmission line on communication peripheral you have to take care of line capacitance etc. The IOs are tested on 50pf load. So length of your PCB etc will be defined by this. however you can reduce the frequency to make long transmissions...

why not to use the external drivers like RS485, 422 etc