6.6 Host MCU Interface Over UART

The BM83 module supports UART commands, which enable an external MCU to control the BM83 module. The following figure illustrates the UART interface between the BM83 module and an external MCU. An external MCU can control the BM83 module over the UART interface and wake up the module with the MFB and P0_0 pins.

Refer to SPKcommandset tool to get a list of functions supported by the BM83 module and how to use the Config Tool for configuring UART and UART command set tool.

Figure 6-8. Host MCU Interface Over UART
Note: For the latest SPKcommandset tool, refer to www.microchip.com/BM83.

The following figures illustrate the timing sequences of various UART control signals.

Figure 6-9. Timing Sequence of Power On/Off
Figure 6-10. Timing Sequence of RX Indication After Power On State
Figure 6-11. Timing Sequence of Power Off State
Timing sequence of Power Off state:
  • For a byte, write: 0.01 ms x 32 clock x 2 = 640 μs.
  • It is recommended to have ramp-down time more than 640 μs during the Power Off sequence to ensure safe operation of the device.
Figure 6-12. Timing Sequence of Power On (NACK)
Figure 6-13. Reset Timing Sequence in No Response From Module to Host MCU

If the BM83 module does not respond to the host MCU’s UART command, the MCU re-sends the UART command. If the BM83 module does not respond within 5 seconds, the MCU forces the system to reset.