The OP8666 has a CAN Bus communication protocol as well, which is the standard protocol widely used in industrial equipment.
In addition, many commercially available battery packs require 12 V enable signal to turn on the battery.
The OP8666 added this additional Battery Enable signals to enable interface to such battery packs.
Note that the output of these protocols is isolated from the main controller, however, they share the same ground among them.
CAN Bus Interface
The OP8666 uses an isolated CAN Transceiver IC ISO1042 from Texas Instruments as a bridge to connect the microcontroller CAN-A to a CAN bus.
Connections with Microcontroller
ISO1042 Pin Name | Controller Pin Name | Controller Pin |
TXD | GPIO31 / CANA_TX | U11 |
RXD | GPIO30 / CANA_RX | T11 |
Battery Enable
The battery enable signal is achieved through isolated optocoupler IC, which turns ON and OFF the output accordingly.
Connection with Microcontroller.
Signal Name | Controller Pin Name | Controller Pin |
Battery Enable | GPIO35 | 193 |
Termination and Wiring
The CAN bus requires a 120R termination resistor at the far ends of the bus.
These resistors can be installed easily on the unused RJ45 connectors.
In addition, it is recommended to use a twisted pair, shielded cable with 100R-120R characteristic impedance such as Belden 3109A for best performance.