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McASPTxFmtSet in StarterWare/L138

Liz
Intellectual 440 points


Hi

I noticed that in the McASP driver, the XFMT is set like this. My question is, what is the purpose of (wordSize >> 2)? If the wordSize is 32, the RBUSEL bit in XFMT is set. Is this a bug?

McASPTxFmtSet(baseAddr, (MCASP_TX_PAD_WITH_0 | MCASP_TX_BITSTREAM_MSB_FIRST                              | MCASP_TX_SYNC_DELAY_1BIT | (wordSize >> 2)                              | ((slotSize/2 -1) << MCASP_XFMT_XSSZ_SHIFT)                              | txMode));

Thanks

  • 0
    TI__Intellectual 2525 points

    Hi Liz,

    You are right. This is a bug. Please find the fix below. The fix will be available with the next release. For now you can modify your McASPTxFmtI2SSet and McASPRxFmtI2SSet as below.

    void McASPTxFmtI2SSet(unsigned int baseAddr, unsigned int wordSize,
                          unsigned int slotSize, unsigned int txMode)
    {
        /* Set the mask assuming integer format */
        McASPTxFmtMaskSet(baseAddr, (1 << wordSize) - 1);

        /* Set the transmit format unit for I2S */
        McASPTxFmtSet(baseAddr, (MCASP_TX_PAD_WITH_0 | MCASP_TX_BITSTREAM_MSB_FIRST
                                 | MCASP_TX_SYNC_DELAY_1BIT
                                 | ((wordSize >> 2) & MCASP_XFMT_XROT)
                                 | ((slotSize/2 -1) << MCASP_XFMT_XSSZ_SHIFT)
                                 | txMode));
    }

    (similar changes apply to Rx function as well)

    Regards,

    Sujith.