SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The procedure in Table 26-353 configures the transmit clock generator of the McASP module.
| Step | Register/Bit Field/Programming Model | Value |
|---|---|---|
| IF transmit clock - XCLK is internally generated | Software test condition | |
| IF high-speed transmit clock - AHCLKX is internally generated based on AUXCLK | Software test condition | |
| Select an internally-generated high-frequency clock. | MCASP_AHCLKXCTL[15] HCLKXM | 0b1 |
| Select the high-frequency clock source polarity: non-inverted or inverted. | MCASP_AHCLKXCTL[14] HCLKXP | 0x- |
| Set the divisor for the internally generated high-frequency clock – AHCLKX in range (1 - 4096). | MCASP_AHCLKXCTL[11:0] HCLKXDIV | 0x- |
| Optional: If McASP transmitter is required to output internally generated high-frequency clock, AHCLKX pin must be set as an output in step 10 of the sequence documented in the Table 26-350. This must NOT be done in current step because the clock control register - MCASP_AHCLKXCTL must be appropriately configured prior to AHCLKX pin outputting a high-speed clock to an external device. | MCASP_PDIR[27] AHCLKX | 0b1 |
| ELSE | ||
| Select an externally-generated high frequency clock (HCLKXDIV divider can not be used). | MCASP_AHCLKXCTL[15] HCLKXM | 0b0 |
| Select the high-speed transmit clock source polarity: non-inverted or inverted. | MCASP_AHCLKXCTL[14] HCLKXP | 0x- |
| Setup an input directon for the AHCLKX pin | MCASP_PDIR[27] AHCLKX | 0b0 |
| ENDIF | ||
| Select an internally-generated transmit clock. | MCASP_ACLKXCTL[5] CLKXM | 0b1 |
| Transmitter samples on rising/falling edge. Select Tx shifting out data on the rising edge if receiver samples on falling edge, and vice versa. | MCASP_ACLKXCTL[7] CLKXP | 0x- |
| Set the divisor for the internally generated transmit clock– ACLKX in range (1 - 32). | MCASP_ACLKXCTL[4:0] CLKXDIV | 0x- |
| Optional: If McASP transmitter is required to output internally generated clock, ACLKX pin) must be set as an output in step 10 of the sequence documented in the Table 26-350. This must NOT be done in current step because the clock control register - MCASP_ACLKXCTL must be appropriately configured prior to ACLKX pin outputting a transmit clock to an external device. | MCASP_PDIR[26] ACLKX | 0b1 |
| ELSE | ||
| Select an externally-generated transmit clock. Note that in this case the AHCLKX signal path and the CLKXDIV divider are NOT used. | MCASP_ACLKXCTL[5] CLKXM | 0b0 |
| Transmitter samples on rising/falling edge. Select Tx shifting out data on the rising edge if receiver samples on falling edge, and vice versa. | MCASP_ACLKXCTL[7] CLKXP | 0x- |
| Setup an input directon for the ACLKX pin | MCASP_PDIR[26] ACLKX | 0b0 |
| ENDIF | ||
| Configure the transmit clock failure detect logic. | See Section 26.6.4.15.6.1, Clock Failure Check Startup. |