8.5.1.3 Daisy Chain Communication

The daisy chain communication is created using differential signaling to minimize Electro-Magnetic Susceptibility (EMS) and Bulk Current Injection (BCI) immunity. The differential communication transmits true and complement data on the COM*P and COM*N pins respectively. In a multiple device stack, there are configurations where the BQ79606A-Q1 are physically located on the same board or located in entirely separate packs connected with twisted-pair wiring.

The BQ79606A-Q1 supports the use of transformers or capacitors to electrically isolate the signals between devices in the stack. For applications that have multiple devices on the same PCB, a single level-shifting capacitor is connected between the COM* pins of the devices. For extremely noisy environments, additional filtering may be necessary. For devices that are separated by cabling, additional isolation components must be used. See Daisy-Chain Differential Bus for specific details on selecting components. The individual transmitters and receivers are enabled/disabled using the DAISY_CHAIN_CTRL register.