Post by thread:Another BASIC SPI bus question

Hi I have another SPI or microwire bus question. I am also looking at extending the output pin capabilities of my PIC by using a 74LS595. I have never used a chip like this before and I would like to use the SPI bus clock and data lines, that I am using to control an SPI eeprom and DAC, for the SCK and RCK pins of the 74LS595. I believe I can use the SI pin like a CS(chip select) Is that correct? It looks like the data isn't clocked in until the SI line is pulsed. If I keep the SI line low when I don't want data shifted in, will it ignore the status of the RCK line as the SPI bus is talking with other chips? Thanks Jon

Serial PIC'n by RL Stevens Square1 Electronics http://www.sq-1.com >>> Jon Petty <spam_OUTPhxsys3TakeThisOuTAOL.COM> 10/30 8:03 PM >>> Hi I have another SPI or microwire bus question. I am also looking at extending the output pin capabilities of my PIC by using a 74LS595. I have never used a chip like this before and I would like to use the SPI bus clock and data lines, that I am using to control an SPI eeprom and DAC, for the SCK and RCK pins of the 74LS595. I believe I can use the SI pin like a CS(chip select) Is that correct? It looks like the data isn't clocked in until the SI line is pulsed. If I keep the SI line low when I don't want data shifted in, will it ignore the status of the RCK line as the SPI bus is talking with other chips? Thanks Jon !