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RM57L843: How to configure mibSPI4ENA pin ?

Tukaram Bolinge
Prodigy 210 points

Part Number: RM57L843

Hello ,

I've interface Hercules RM57L843 (SPI Master) to ADSP-BF609 processor (SPI Slave) through SPI  interface. In DSP one of the GPIO pin is connected to ENA (SPI4)  pin of hercules. If slave wants to initiate communication to master, how this functionality can be achieved using SPI ENA pin. 

Is it necessary that while slave drives ENA pin , what should be status of chip select pin ? whether it should be continuously high or low ?

  • 0
    TI__Guru**** 201086 points

    Hello,

    The slave will drive the signal SPIENA low when new data is written to the slave shift register and the slave has been selected by the master (SPICS is low). If the slave is deselected by the master (SPICS goes high), the slave SPIENA signal is driven high.

    This is the timing diagram:

  • 0 in reply to QJ Wang
    Prodigy 210 points

    Hello,

    As mentioned ADSP-BF609 is slave and HERCULES RM57l843 is SPI master. Now if slave wants to communicate with master, it has to make high to low transition on ENA pin. Once there is transition on ENA pin 

    master will knows that slave wants to communicate with it  and it will send clocks to slave.

    We have configured ENA pin in SPI mode. Do we need to monitor ENA pin at master side or do we get interrupt at master for transition on ENA ? 

    If we get interrupt at master side then we can send clocks from same interrupt routine. This is my understanding is it correct ?

    Also please send me steps for initiating communication from slave to master (RM57L843) . 

  • 0 in reply to Tukaram Bolinge
    TI__Guru**** 201086 points

    SPIENA is a wait signal. It doesn't generate interrupt.

    1. If SPIENA is used, it's default level is HIGH

    2. SPI master writes data to SPIDAT1 register to start transfer

    3. Since SPIENA = High, master holds the transfer

    4. Slave pull the SPIENA LOW

    5. Master transfers the data in SPIDAT1