SLAU962A December 2025 – June 2026 MSPM33C321A , MSPM33C321A-Q1
The frame length is calculated as the number of I2S_BCLK cycles from a rising or falling I2S_WCLK to the corresponding edge on the next frame. In a frame, the word length or number of data bits per slot/channel is configured through FMTCFG.WORDLEN which has a minimum value of 8 bits and maximum value of 32 bits. The I2S_WCLK is used in target mode to automatically detect the number of I2S_BCLK used for a channel for dual-phase formats:
The data that is transmitted or received on the I2S_ADx comes from the FIFO which can be configured using the FMTCFG.MEMLEN32 as 16-bit or 32-bit data per entry in the FIFO.
FMTCFG.MEMLEN32 = 0
When configured as 0, each FIFO entry holds data in the lower 16-bit and the upper 16-bit is unused. This setting must only be used when FMTCFG.WORDLEN ≤ 16-bits. If word length programmed is less than 16-bits then sample words are truncated when transmitting and zero-padded when receving in the least significant bit position as shown in Figure 27-2.
FMTCFG.MEMLEN32 = 1
When configured as 1, each FIFO entry holds two samples when FMTCFG.WORDLEN ≤ 16-bits or a single entry when FMTCFG.WORDLEN > 16-bits. If the word length programmed results in truncation on transmit or zero-padding on receive, the operation happens in the least significant bit position as shown in Figure 27-3.