Overview

The MAX17851 SPI to UART safety monitoring bridge translates communication from SPI format to universal asynchronous receiver transmitter (UART) format specially designed to interface with Maxim's Battery Management Data Acquisition System. The safety monitoring bridge enables robust communication with baud rates extending up to 4Mbps in both single and dual daisy-chain system architectures. High throughput, dual UART systems can read 96 cells of battery voltages within 1173us.

The UART is ISO26262 compliant for automotive safety integrity level (ASIL) D systems providing detection of message corruption, delay, loss, and insertion through the embedded UART communication lock step safety measure state machine (LSSM). The MAX17851 self verifies all communication within the message payload to simplify the software development on the host microcontroller.

Additionally, the MAX17851 monitors the host microcontroller communication to detect any failures. In the event of a communication failure with the host, the MAX17851 first tries to automatically recover communication. If unsuccessful, it assumes control. The MAX17851 can then optionally re-configure the daisy chain network that allows battery conditions to continue to be monitored. This allows for continued safe system operation. Lastly, the MAX17851 provides contactor signalling in the event that the battery conditions fall outside of the programmed range, putting the complete system into a failsafe state.