SPRUIV7B May 2022 – September 2023 AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP
The procedure in Table 12-23 initializes a MCASP serializer n transmitter(s) to operate in TDM-mode after a power-on reset (POR). This is used for I2S (2-slot TDM) and other TDM-based audio protocols transmission.
Before performing MCASP global initialization, If external clock ACLKR is used, it must be running already for proper synchronization of the MCASP_GBLCTL register.
Step | Register/Bit Field/Programming Model | Value |
---|---|---|
1. Apply software reset to different MCASP transmit components. | MCASP_GBLCTL[12-8] | 0x00 |
2. Poll the bits to ensure the active reset value (0x00) is successfully latched into the register. | MCASP_GBLCTL[12-8] | =0x00 |
3. Configure the local power management. | MCASP_PWRIDLESYSCONFIG[1-0] IDLE_MODE | 0x1 |
4. Configure the transmit format unit. | See Section 12.1.1.5.1.2.3.1. | |
5. Configure the transmit frame sync generator. | See Section 12.1.1.5.1.2.3.2. | |
6. Configure the transmit clock generator. | See Section 12.1.1.5.1.2.3.3. | |
7. Program all bits - XTDMSk, where k = 0 to 31, according to the time slot characteristics desired (positions of active versus inactive slots within a frame). | MCASP_XTDM[k] XTDMSk, where k = 0 to 31(4) | 0x- |
8. Configure the desired n-th serializer for transmit mode operation.(3) | MCASP_SRCTLn[1-0] SRMOD; n = 0 to 15 | 0x1 |
9. Setup all active transmitters to operate in TDM mode. | MCASP_DITCTL[0] DITEN | 0x0(2) |
10. Configure the MCASP pins functionality. | See Section 12.1.1.5.1.2.3.4. | |
11. Optional: Configure a MCASP Tx channel for loopback operation (TDM mode only) in MCASP_DLBCTL [31-0]. | See Section 12.1.1.4.14.1, Loopback Mode Configurations. | 0x- |
12. Release from reset state the divider that outputs the AHCLKR clock. See(1) | MCASP_GBLCTL[9] XHCLKRST | 0x1 |
13. Poll the bit to ensure that it is successfully latched in the register. | MCASP_GBLCTL[9] XHCLKRST | =0x1 |
14. Release from reset state the divider that outputs the ACLKR clock. See(1) | MCASP_GBLCTL[8] XCLKRST | 0x1 |
15. Poll the bit to ensure that it is successfully latched in the register. | MCASP_GBLCTL[8] XCLKRST | =0x1 |