Sai Pins And Internal Signals; Main Sai Modes; Table 171. Sai Internal Input/Output Signals; Table 172. Sai Input/Output Pins - ST STM32F446 Series Reference Manual

RM0390
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.
28.3.2

SAI pins and internal signals

Internal signal name Signal type
sai_a_gbl_it/
sai_b_gbl_it
sai_a_dma,
sai_b_dma
sai_sync_out_sck,
sai_sync_out_fs
sai_sync_in_sck,
sai_sync_in_fs
sai_a_ker_ck/
sai_b_ker_ck
sai_pclk
Name
SAI_SCK_A/B
SAI_MCLK_A/B
SAI_SD_A/B
SAI_FS_A/B
28.3.3

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.
Both SCK_x, FS_x and MCLK_x are configured as outputs.

Table 171. SAI internal input/output signals

Output Audio block A and B global interrupts.
Input/output Audio block A and B DMA acknowledges and requests.
Internal clock and frame synchronization output signals
Output
exchanged with other SAI blocks.
Internal clock and frame synchronization input signals
Input
exchanged with other SAI blocks.
Input Audio block A/B kernel clock.
Input APB clock.

Table 172. SAI input/output pins

Signal type
Input/output Audio block A/B bit clock.
Output Audio block A/B master clock.
Input/output Data line for block A/B.
Input/output Frame synchronization line for audio block A/B.
RM0390 Rev 4
Serial audio interface (SAI)
Description
Comments
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