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Data not shifted into Shift Register from TX FIFO or RX FIFO : SPI

Question asked by Samyukta Ramnath on May 22, 2015
Latest reply on Jun 1, 2015 by Samyukta Ramnath

Hello all,

I am trying to get an ADAS1000SDZ Analog Devices front end and a K53 Tower Kinetis microcontroller to talk to each other, with the AFE as slave and microcontroller as master. While doing so, I notice that when I push data into the TX FIFO registers, they are getting updated, but the TXCTR registers aren't getting updated, which means that the TX FIFO data isn't getting sent to the shift register and consequently, nothing is appearing on the Master SOut pin. I have confirmed this by actually checking the Master Out pin, and seeing that it is 0. My chip select is always held low, so the slave is always selected (I have only one slave, as of now). Since the data isn't getting sent to the analog front end, I am not able to set any control registers or send any read commands to the slave. Therefore, it is not sending back any data.

Similarly, no data is getting received into the shift register into the RX FIFO. I have set SPI_MCR_ROOE which says that in case of an overflow, received data must still be shifted into the shift register and after that into the RX FIFO.

I wanted to know if there is anything else I must to do to ensure that the data in the TX FIFO is actually sent out into the Sout pin of the microcontroller. Shouldn't it happen automatically?

Thanking you

Samyukta

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