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how to use QSPI to control other chip?

Question asked by Blackrose on Dec 27, 2012
Latest reply on Jan 6, 2013 by Blackrose

Dear all:

        I used  QSPI on mcf52259 to connect mcp2515.My target is through CAN-bus communication with other nodes.Therefore i extend other CAN controller with SPI.The chip of mcf52259 has a QSPI to control SPI bus.I didn't know somethings when i read that manual.Here is questions

       1.It has a CMD RAM of 16Bytes.Here is my operation(pseudo code)

           QAR = 0x20

           QDR = READ_CMD

        QDR's size is 2Bytes, But CMD RAM only use 1Byte.And QCR is accessed using the upper byte of the QDR.Is it means the high(1Byte) of 2Bytes for QCR and low of 2Bytes for CMD RAM?

       2. QSPI has 16 entries.Each entry has CMD RAM,TX RAM and RX RAM.Most slave devices receive CMD need pulling CS low.Therefore, i must pulling CS low or high when every entry execute  before and after on transfer start. Is it correct?

 

Thanks

Kevin Chen

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