multiple SPI

Questions on control of serial busses
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Joined: Fri Oct 19, 2012 5:11 am

multiple SPI

Post by YahooArchive »

>On the topic of SPI, how many
>groups of 3 pins can be used at one time as SPI Ports, or is there
>only one dedicated SPI port on the ArmExpress or ArmMite? any
>advantage of multiple SPI ports versus one SPI port, with multiple
>Chip selects, to enable 3 or 4 SPI devices

SPI can be done any any set of 3 pins (assuming a CS)

Best would be to use the same 2 pins for CLK and DATA and then seperate
pins for CS for each device (thats how the ARMweb does it). This would
allow quite a few devices. If you find you need more parts or to chew
up less pins, a 74HCT138 to turn 3 lines into 8.

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