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TMS320F28335: Operation as an SPI slave: Is it possible to output the enable/disable status of the current GPIO pins in CCS based on the incoming bit data?

HongMin Kim
Prodigy 30 points
Part Number: TMS320F28335

Tool/software:

Hello to all

I am currently using the MCP2210 SPI module as an SPI Master and the F28335 DSP as an SPI slave. What I want to achieve is that when the MCP2210 sends any SPI data to the DSP, the corresponding GPIO pin is enabled based on the activated bit. (e.g., receiving 0x0001 data -> enabling GPIO0 pin, receiving 0x0002 data -> enabling GPIO1 pin, etc.)

Additionally, and more importantly, I am currently transmitting a total of 16 bits of data, but I want only the 12 bits to activate the GPIO pins according to the activated bits mentioned above. The remaining 4 bits should be used to output the status of which GPIO pins are currently enabled to CCS.

Is it possible to achieve this functionality? If so, I would appreciate any advice on what code needs to be written.

The attached picture shows the current code I am using to activate GPIO pins based on the bits, and another picture shows the received data displayed on CCS when sending SPI data to the DSP via the MCP2210_SPI Terminal program.

Best regards,

  • 0
    TI__Mastermind 20810 points

    Hello,

    I cannnot debug/write code for you, but I can offer some suggestions:

    If you are transmitting 16 bits of data, the chip select line will need to be low the full time so that the slave/peripheral device is actively receiving the data. You could just send the 16-bit transmissions and then break it up (12-bit and 4-bit) in software after you read it - would that work for your application?

    I suppose you could alternatively send the 12 bits of data and other 4 bits in separate transmissions, but given that you need to define your SPI character length (it would have to be at least 12 to accommodate your 12-bit data transmissions), you would have to handle any extra bits (when sending the 4-bit status within a 12-bit transmission) in software after receiving.

    Best Regards,

    Allison