SPRUIV7B May 2022 – September 2023 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP
The procedure in Table 12-20 configures the transmit frame synchronization generator of the MCASP module.
The same bit - MCASP_ACLKXCTL[6] ASYNC which is used to determine if MCASP receivers and transmitters work synchronously on the same clock, is also used to define if receiver frame sync is derived from the transmit frame sync generator, or generated independently in the receiver (either inernally or externally sourced). Hence, the settings in below table Table 12-20 have no effect, if MCASP_ACLKXCTL[6] ASYNC = 0.
Step | Register/Bit Field/Programming Model | Value |
---|---|---|
Select number of TDM slots per frame. Must be set to 0x2, in case of an I2S-reception. For more details on frame-sync generator, refer to Section 12.1.1.4.2.3. | MCASP_AFSRCTL[15-7] RMOD | 0x-(1) |
Choose the receive frame sync width -single bit/single word. For more details on frame-sync generator, refer to Section 12.1.1.4.2.3. | MCASP_AFSRCTL[4] FRWID | 0x- |
Select start of received frame sync polarity - rising /falling edge. For more details on frame-sync generator, refer to Section 12.1.1.4.2.3. | MCASP_AFSRCTL[0] FSRP | 0x- |
IFreceive frame sync - FS is internally generated | Software test condition | |
Select internally- generated receive frame sync. For more details on frame-sync generator, refer to Section 12.1.1.4.2.3. | MCASP_AFSRCTL[1] FSRM | 0b1 |
If MCASP receiver is required to output internally generated frame, AFSR pin must be set as an output in step 9 of the sequence documented in the Table 12-18. This must not be done in current step because the frame control register - MCASP_AFSXCTL must be appropriately configured prior to AFSR pin outputting a frame to an external device. | MCASP_PDIR[31] AFSR | 0b1 |
ELSE | ||
Select externally- generated receive frame sync. For more details on frame-sync generator, refer to Section 12.1.1.4.2.3. | MCASP_AFSRCTL[1] FSRM | 0b0 |
Setup the AFSR pin as input (device level: MCASPi_AFSR) | MCASP_PDIR[31] AFSR | 0b0 |
ENDIF | ||
To generate MCASP receive frame sync in receiver logic, select an asynchronous frame sync. | MCASP_ACLKXCTL[6] ASYNC | 0b1 |