SBASAU2 May 2024 PCM1841-Q1
ADVANCE INFORMATION
The rising edge of FSYNC starts the data transfer in TDM mode (also known as DSP mode) with the slot 0 data first. Immediately after the slot 0 data transmission, the remaining slot data are transmitted in order. FSYNC and each data bit is transmitted on the rising edge of BCLK (except the MSB of slot 0 when TX_OFFSET equals 0). Figure 6-1 to Figure 6-4 illustrate the protocol timing for TDM operation with various configurations.
For proper operation of the audio bus in TDM mode, the number of bit clocks per frame must be greater than, or equal to, the number of active output channels times the 32-bits word length of the output channel data. The device transmits a zero data value on SDOUT for the extra unused bit clock cycles. The device supports FSYNC as a pulse with a 1-cycle-wide bit clock, but also supports multiples as well.