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9 years, 1 month ago.
SPI bidirectional communication: Requires reset on the slave device to communicate
Hi
I have setup two Nucleo F401RE boards to communicate with each other with one being master and other as a slave.
The slave device only communicates if it is powered after the Master board. In other terms, if slave board is powered before Master, then the slave requires a push button reset to enable communication.
Has anyone noticed this? What could be the reason behind it? Is there any solution?
Thanks a lot!
1 Answer
9 years, 1 month ago.
You probably get some spurious pulses on the SCK line and/or CS lines of the slave which causes the SPI to start a RX operation. The slave code receive statemachine may get confused and hang. Try to toggle the CS line of the master a few times to reset the SPI engine on the slave. Series resistors in the MOSI, MISO, SCK and CS lines may reduce or solve the problem.