Software Design Overview

The software is responsible for

• Periodically measuring the battery pack

• If the pack is unsafe, the shutdown sequence will run

• Balancing battery cells to keep the pack safe

• Periodically sending data to Telemetry

Software Flow

Software Stack

Board Support Package (BSP)

The BSP interfaces with peripherals and implements interrupt handlers.

Drivers

Drivers interface with external hardware. The software for the BPS has drivers for:

• CAN

• EEPROM

• LTC6811 (Voltage and Temperature)

• LTC2315 (Amperes)

Real Time Operating System (RTOS)

The RTOS uses a scheduler to run multiple threads. Running these threads creates “pseudo-concurrency”.

The RTOS ensures that safety critical tasks will not be blocked by non-safety critical tasks.

We use custom RTOS wrappers to allow easy porting. Currently, we are wrapping for Micrium uC/OS-III RTOS.

Applications (Apps)

The BPS Apps consist of threads/tasks and functions that interpret measurements. The following tasks make up the BPS’ engine and are shown from highest to lowest priority:

• Initialization

• Fault State

• Check Contactor

• Pet Watchdog

• Voltage/Temperature monitor

• Amperes monitor

• Battery Balancing

• Log Information

• CAN Message Consumer

• Command Line Interface (CLI)

• Idle

Descriptions of what each task does can be found in the Tasks section.