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TMS320F28335 McBSP max data rate in SPI mode?

Paul Joseph
Expert 2795 points

Other Parts Discussed in Thread: TMS320F28335

If I use the McBSP in SPI mode on an tms320f28335, is my max data rate 25 Mbit/sec, or is there some other limit?

  • 0
    TI__Expert 3760 points

    Paul,

    In master mode, yes, this is true - and the 25 MHz limit is driven by the I/O output buffer speeds.

    In SPI slave mode, the McBSP is limited in that CLKX has to be a minimum of 8 CLKG ccles (where CLKG = LSPCLK/2, and the maximum LSPCLK = 75 Mhz).

    Therefore the maximum CLKX speed in slave mode is LSPCLK/16 = 4.6875 MHz.

  • 0 in reply to Chrissy Chang
    Expert 2795 points

    Thank you, does this also hold for the hardwired SPI port?

  • 0 in reply to Paul Joseph
    TI__Expert 3760 points

    Paul -

    No, the dedicated SPI port has the following speed limitations:

    Master mode transmit 25-MHz MAX, master mode receive 12.5-MHz MAX
    Slave mode transmit 12.5 -MHz MAX, slave mode receive 12.5 -MHz MAX.

    All of the above information is available in the Electricals section of the device data sheet (look under Electrical Specifications -> McBSP Timings -> McBSP as SPI, and Look under Electrical Specifications ->SPI Timings)