SLASFM6 October 2026 TAS2573
ADVANCE INFORMATION
The device provides a flexible Audio Serial Interface (ASI) port. The port can be configured to support a variety of formats including stereo I2S, Left Justified, and TDM. Mono audio playback is available via the SDIN pin. The SDOUT pin is used to transmit echo reference stream to enable echo cancellation algorithms in a host processor connected to the device.
The TDM serial audio port supports up to 16 32-bit time slots at 44.1/48kHz, 8 32-bit time slots at a 88.2/96kHz sample rate and 4 32-bit time slots at a 176.4/192kHz sample rate. The device automatically detects the number of time slots and this does not need to be programmed. PCM data sampling rate and SBCLK to FSYNC ratio detected on the TDM bus is reported back on the read-only register bits FS_RATE_DETECTED[2:0] and FS_RATIO_DETECTED[3:0] respectively.
| FS_RATE_DETECTED[2:0] (Read Only) |
Setting |
|---|---|
| 000 | Reserved |
| 001 | 14.7kHz / 16kHz |
| 010 | 22.05kHz / 24kHz |
| 011 | 29.4kHz / 32kHz |
| 100 (default) |
44.1kHz / 48 kHz |
| 101 | 88.2kHz / 96kHz |
| 110 | 176.4kHz / 192kHz |
| 111 | Error condition |
The RX_SLEN[1:0] register bits set the length of the RX time slot to 16, 24 or 32 (default) bits. The length of the audio sample word within the time slot is configured by the RX_WLEN[1:0] register bits. The RX port left justifies the audio sample within the time slot by default, but this can be changed to right justification via the RX_JUSTIFY register bit.
The device supports mono and stereo down mix playback ([L+R]/2). By default the device playback is mono from the time slot equal to the I2C base address offset (set by the AD1 and AD2 pins) for playback. The RX_SCFG[3:0] register bits can be used to override the playback source to the left time slot, right time slot or stereo down mix set by the RX_SLOT_L[3:0] and RX_SLOT_R[3:0] register bits.
| RX_SCFG[3:0] | RX Channel |
|---|---|
| 0000 | Channel with time slot equal to I2C address offset |
| 0001 | Left channel |
| 0010 | Right channel |
| 0011 | Stereo downmix (L+R)/2 |
If time slot selection places reception either partially or fully beyond the frame boundary, the receiver returns a null sample equivalent to a digitally muted sample.
The TDM port can transmit the echo reference streams on the SDOUT pin. This enables echo and noise cancellation algorithms in the host processor. The echo reference stream is transmitted on the SDOUT pin. Setup of the transmission path is done using PPC3 Software Section 6.4.1.