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What I don't understand in your solution is that, if MOSI comes from the uC, how do the bits from the first CPLD spill over onto the next CPLD in the cascade?
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You can treat your SPI bus as a common bus with MOSI going to all the devices in parallel, and MISO coming from all in parallel. This is where the device ID would be useful, as only the selected device would drive the common MISO bus.
Alternatively, you do the JTAG trick where the shift-register passes through all the devices and then loops back to the master. That'll provide the read-back function.
Cheers,
Dave
Honored Contributor
