BMS STM32F412 - ADBMS6822 - ADBMS6830 Project

📘 Overview

This project implements a Battery Management System (BMS) interface using the Analog Devices ADBMS6822 IC, with the STM32F412RET MCU.
It handles communication with the daisy-chained ADBMS6830 over isoSPI, retrieves battery monitoring data, manages EEPROM over I²C, monitors IVT sensor data via Classic CAN, and streams measurements to a Node-RED dashboard via UART.

The system is designed to:

• Communicate with a daisy-chained stack of ADBMS6830 devices.
• Perform wake-up, configuration, and data readout cycles.
• Handle CAN communication with an IVT sensor and charger.
• Store configuration or log data in an external EEPROM (via I²C).
• Use periodic timers for scheduled tasks and delay measurements.
• Stream data over UART for real-time dashboards.

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🛠️ Hardware Setup

• MCU: STM32F412RETx
• Communication:
  • SPI1 – Communication with ADBMS6822 (2 Mbps)
  • CAN1 – Communication with POWERTRAIN network (1 Mbps)
  • CAN2 – Communication with Battery Charger (125 Kbps)
  • I²C – EEPROM (24xx series)
  • USART1 (DMA) – Data stream to Node-RED (230400 baud)
• Peripherals:
  • TIM2, TIM5 – microsecond timers for delay functions
  • TIM8 – periodic interrupt every 800 ms
  • GPIO PC13 – user push button (external interrupt)

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📦 Features

• ✅ SPI communication with ADBMS6822 (includes wake-up and PEC handling)
• ✅ Classic CAN communication (bxCAN)
• ✅ EEPROM driver with RTOS-aware delay and locking
• ✅ UART streaming to Node-RED dashboards
• ✅ External interrupt handling for user button
• ✅ Multiple periodic timers
• ✅ CRC10/CRC15 calculation for PEC integrity checks

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🌀 SPI Communication (ADBMS6822)

• Baud rate: 2 Mbps
• Mode: SPI Mode 3 (CPOL = 1, CPHA = 1)
• NSS: Controlled manually via GPIO (software chip select)

Wake-up example:

void bms_wakeupChain(void) {
    for (uint8_t ic = 0; ic < TOTAL_IC; ic++) {
        bms_csLow();
        HAL_Delay(1);
        bms_csHigh();
        HAL_Delay(1);
    }
}

🛠️ Tips for avoiding PEC errors:

• Verify SPI mode and timing match ADBMS6822 datasheet.
• Ensure CS toggling meets wake-up timing specs.
• Validate CRC10/CRC15 functions.
• Confirm delay timers (bms_delayUs, bms_delayMsActive) are accurate.

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⏱️ Timers

Timer	Purpose	Interval
TIM2	Delay functions (µs)	µs scale
TIM5	Delay / wake-up counter	µs scale
TIM8	Periodic task scheduler	800 ms

Example configuration:

htim8.Instance = TIM8;
htim8.Init.Prescaler = 63999;  // 64 MHz / 64000 = 1 kHz
htim8.Init.Period = 799;       // 1 kHz / 800 = 1.25 Hz (~800 ms)
HAL_TIM_Base_Start_IT(&htim8);

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🧠 External Interrupt (User Button)

void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) {
    if (GPIO_Pin == GPIO_PIN_13) {
        bmsState = (bmsState == ACTIVE) ? INACTIVE : ACTIVE;
    }
}

➡ Make sure EXTI15_10_IRQn is enabled in stm32f4xx_it.c.

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🗃️ EEPROM (24xx Series)

EEPROM driver initialization example:

EE24_HandleTypeDef ee24;
EE24_Init(&ee24, &hi2c1, 0xA0);

Supports both bare-metal and RTOS modes, with built-in lock and delay handling.

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📊 Node-RED Integration via UART

The firmware streams data to Node-RED over USART1 (DMA) at 230400 baud.
Data is sent as JSON-formatted strings and can be parsed directly in Node-RED dashboards.

Example payload:

{
  "dieTemp": 24.5,
  "SegVoltage": 37.47,
  "rth_temps": { "ic": 1, "temps": [23.4, 24.1, 25.0] }
}

The included flows.json file provides a prebuilt Node-RED dashboard with:

• Real-time gauges for temperatures and voltages
• Per-cell voltage tables
• Line charts for temperature sensors
• Fault and CAN status indicators
• Debug console for raw UART logs

👉 To use: Import flows.json into Node-RED via Import > Clipboard.

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🧪 Debugging PEC Errors

If you see:

WARNING! PEC ERROR - IC: 1, IC1: 0xF3, 0xFF, 0xFF, 0xFF, 0xFF, 0xFB, CC: 61

✔ Check SPI polarity (CPOL=1) and phase (CPHA=1)
✔ Verify manual CS timing between transactions
✔ Validate CRC10/CRC15 calculation in bms_utility.c
✔ Ensure correct wake-up delay (use bms_delayUs())

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📁 Project Structure

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🧰 Build Notes

• Enable float support for printf: add -u _printf_float to linker flags.
• Ensure SPI runs near 2 Mbps by adjusting APB2 clock and SPI prescaler.

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✅ Status

• SPI communication with ADBMS6822 verified
• PEC (CRC10/CRC15) verified
• CAN communication functional
• EEPROM read/write functional
• UART communication with Node-RED operational
• Timers and EXTI working

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📜 License

This project is intended for internal development and testing of BMS communication firmware using STM32F4 microcontrollers.