ST STM32L4 5 Series User Manual

Serial audio interface (SAI) RM0351
1450/1830 DocID024597 Rev 5
The audio sub-block can be a transmitter or receiver, in master or slave mode. The master
mode means the SCK_x bit clock and the frame synchronization signal are generated from
the SAI, whereas in slave mode, they come from another external or internal master. There
is a particular case for which the FS signal direction is not directly linked to the master or
slave mode definition. In AC’97 protocol, it will be an SAI output even if the SAI (link
controller) is set-up to consume the SCK clock (and so to be in Slave mode).
Note: For ease of reading of this section, the notation SAI_x refers to SAI_A or SAI_B, where ‘x’
represents the SAI A or B sub-block.
43.3.2 SAI pins and internal signals
43.3.3 Main SAI modes
Each audio sub-block of the SAI can be configured to be master or slave via MODE bits in
the SAI_xCR1 register of the selected audio block.
Master mode
In master mode, the SAI delivers the timing signals to the external connected device:
• The bit clock and the frame synchronization are output on pin SCK_x and FS_x,
respectively.
• If needed, the SAI can also generate a master clock on MCLK_x pin.
Table 251. SAI internal signals
Internal signal name Signal type Description
sai_a_gbl_it/
sai_b_gbl_it
Digital
output
Audio block A and B global interrupts.
sai_a_dma,
sai_b_dma
Digital
input/output
Audio block A and B DMA acknowledges and requests.
sai_sync_out_sck,
sai_sync_out_fs
Digital
output
Internal clock and frame synchronization output signals
exchanged with other SAI blocks.
sai_sync_in_sck,
sai_sync_in_fs
Digital input
Internal clock and frame synchronization input signals
exchanged with other SAI blocks.
sai_a_ker_ck/
sai_b_ker_ck
Digital input Audio block A/B kernel clock.
sai_pclk Digital input APB clock.
Table 252. SAI pins
Name Signal type Comments
SAI_SCK_A/B
Digital
input/output
Audio block A/B bit clock.
SAI_MCLK_A/B
Digital
output
Audio block A/B master clock.
SAI_SD_A/B
Digital
input/output
Data line for block A/B.
SAI_FS_A/B
Digital
input/output
Frame synchronization line for audio block A/B.

ST STM32L4 5 Series Specifications

General

Brand	ST
Model	STM32L4 5 Series
Category	Microcontrollers
Language	English