10.3 Multi-Drop System

A third application does not use the daisy-chain interface. Instead, all devices on the bus are seen as base devices. In this mode, all devices are connected in parallel and do not support the auto-addressing scheme. The addressing must be done sequentially using the GPIOs or individual writes before assembly. No specific bus arbitration is done, however, broadcast reads are supported using a similar methodology as the stack interface. In the multi-drop setup where a CAN transceiver is used (as in Figure 66), all devices RX inputs receive the TX communications from the other devices on the bus. It this configuration, the IC waits for the next highest address device to respond. Once it receives that response (must be CRC validated), it send its own response. The host must leave the bus clear during responses. There is no collision arbitration built in, where the BQ79606A-Q1 knows its communication has been stepped on. If the communication is interrupted (either by collision or failed CRC check) before all devices have responded, none of the remaining devices respond. A communication clear must be sent to clear the bus. Stack Read, Stack Write, and Write Reverse Direction are not supported in multi-drop configuration.

Figure 67. System Application with Multi-Drop Base Devices