SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
The procedure in Table 26-350 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. | PWRIDLESYSCONFIG[1:0] IDLE_MODE | 0x1 |
4. Configure the transmit format unit. | See Section 26.6.5.1.2.3.1. | |
5. Configure the transmit frame sync generator. | See Section 26.6.5.1.2.3.2. | |
6. Configure the transmit clock generator. | See Section 26.6.5.1.2.3.3. | |
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_TXTDM [ k ] XTDMSk, where k=0 to 31(4) | 0x- |
8. Configure the desired n-th serializer for transmit mode operation. (3) | MCASP_XRSRCTLn[1:0] SRMOD; | 0x1 |
9. Setup all active transmitters to operate in TDM mode. | MCASP_TXDITCTL[0] DITEN | 0x0(2) |
10. Configure the McASP pins functionality. | See Section 26.6.5.1.2.3.4. | |
11. Optional: Configure a McASP Tx channel for loopback operation (TDM mode only) in MCASP_LBCTL [31:0]. | See Section 26.6.4.14.1, 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 |