I2S sample rate register
| TX_BCK_DIV_NUM | Bit clock configuration bits in transmitter mode. |
| RX_BCK_DIV_NUM | Bit clock configuration bits in receiver mode. |
| TX_BITS_MOD | Set the bits to configure bit length of I2S transmitter channel, the value of which can only be 8, 16, 24 and 32. |
| RX_BITS_MOD | Set the bits to configure bit length of I2S receiver channel, the value of which can only be 8, 16, 24 and 32. |