In the noncommunicable conditions, such as in SHUTDOWN or SLEEP mode, or in the loss of communication situations when host need to send an instruction for a reset or power down as a communication recovery attempt, a Ping or Tone is a form of communication to the device for a specific action. For the detailed Ping and Tone description, see the Ping and Tone section of the BQ79616 16-Series Battery Monitor, Balancer, and Integrated Hardware Protector Data Sheet.

A ping is a specific high-low-high signal that MSPM0 send to BQ79616's Rx pin through UART or IO. Ping is used on the base device as only the base device is connected to MSPM0 which the UART Rx is accessible. The device detects different low times of the ping signal, which is shown in Figure 3-5.

The communication pings are referring to the WAKE ping, SLEEPtoACTIVE ping, SHUTDOWN ping, and HW_RESET ping. These pings instruct the BQ79616 to a specific power mode when normal communication is not available.

A tone is a fixed number of couplets (pulses) with a specified polarity (all “+” or all “–”) sent through the differential vertical interface COMH and COML ports. Tone is used on stack devices as only the COMH/L ports are accessible. The number of couplets for transmission is always greater than the number of couplets needed for detection.