SPI Daisy Chain

Can the Stellaris MCUs be used as SPI masters with the slave devices connected in a daisy chain (e.g. using a single select line)?


1 Reply

  • The SSI on the Stellaris MCUs can be used with daisy-chained slaves. Of course, the slaves must be capable of supporting this as well.

    There is one consideration to keep in mind. The SSI on the Stellaris MCUs supports a frame size from 4 to 16 bits. If the combined size of the shift registers in the daisy-chained slaves is greater than 16, then multiple transmit frames will be required for a single write to the daisy-chained slaves. Since the SSI select line will not remain active over multiple transmit frames, a software controlled GPIO would need to be used as the select line.

    Post edited by: LMI Kyle, at: 2007/12/07 14:27