9.4.3.3 Multi-Devices PWM Phase Synchronization
This device support up to 4 phases selection for the multi devices application system. For example, when a system integrated 4 devices, user can select phase 0/1/2/3 for each device by register PHASE_CTRL (0x6A), which means there is a 45 degree phase shift between each device to minimize the EMI.
Recommend to do the Phase Synchronization with I2S clock during the Startup Phase.
- Halt I2S clock.
- Configure each device phase selection and enable the phase synchronization. For example: Register 0x6A = 0x03 for device 0; Register 0x6A = 0x07 for device 1; Register 0x6A = 0x0B for device 2; Register 0x6A = 0x0F for device 3. There should be a 45 degree PWM phase shift between each device to minimize the EMI.
- Configure each device into HIZ mode.
- Provide I2S to each device. Phase synchronization for all 4 devices will be automatically done by internal sequence.
- Initialize the DSP code. (This step can be skipped if only need to do the PWM Phase Synchronization).
- Device to Device PWM phase shift should be fixed with 45 degree.