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Adding Custom Board Support to dingoPDM Firmware

Overview

This guide walks you through adding support for a custom PDM board to the dingoPDM firmware. By following these steps, you'll build the firmware to run on your custom hardware while reusing existing functionality.

Hardware

Pins

The pins you need depend on which Profets (switching devices) you're planning to use.

BTS7002-1EPP

Pin Type Count Name Purpose
Analog Input 1 IS Current feedback
Digital Output 1 IN Drive transistor ON/OFF (PWM-enabled)
Digital Output 1 DEN Enable current sensing

BTS7008-2EPP Variant

Pin Type Count Name Purpose
Analog Input 1 IS Current feedback
Digital Output 1 IN Drive transistor ON/OFF (PWM-enabled)
Digital Output 1 DSEL Select which output's current is measured
Digital Output 1 DEN Enable current sensing

Note: The BTS7008-2EPP uses a single shared current feedback channel with multiplexing via DSEL, while the BTS7002-1EPP has a dedicated feedback pin. All IN pins must support PWM; other outputs can use regular GPIO.

PCB Design

To Do

Schematic recommendations and layout guidelines

Firmware

The dingoPDM firmware is modular—adding a new board requires minimal changes outside the boards/ folder. Follow these steps in order:

Overview

  • Copy and rename an existing board folder
  • Update the .ld linker script
  • Configure board.mk
  • Define pins in board.h
  • Set output count in port.h
  • Declare outputs in hw_devices.cpp
  • Update message handling in msg.cpp
  • Update root Makefile
  • Add PWM configuration in port_pwm.h
  • Enable timers in mcuconf.h (if needed)

Files

Linker Script (.ld)

Location: boards/your_board_name/

Changes needed: - Rename the .ld file to match your board name exactly

Board Configuration (board.mk)

Location: boards/your_board_name/

Example 
# List of all the board related files
BOARDSRC = ./boards/your_board_name/board.c

# Required include directories
BOARDINC = ./boards/your_board_name

Pin Definitions (board.h)

Location: boards/your_board_name/

This file initializes all MCU pins and their configurations. Define each pin type with the settings below:

Note

Refer to ChibiOS documentation on board.h configuration

IN Pin Configuration 
Mode     = OUTPUT
Otype    = PUSHPULL
Ospeed   = HIGH
Pupdr    = PULLDOWN
Odr      = LOW
Afio     = AF
DEN Pin Configuration 
Mode     = OUTPUT
Otype    = PUSHPULL
Ospeed   = HIGH
Pupdr    = PULLDOWN
Odr      = LOW
Afio     = AF
DSEL Pin Configuration 
Mode     = OUTPUT
Otype    = PUSHPULL
Ospeed   = HIGH
Pupdr    = PULLDOWN
Odr      = LOW
Afio     = AF
IS Pin Configuration 
Mode     = ANALOG
Otype    = PUSHPULL
Ospeed   = LOW
Pupdr    = FLOATING
Odr      = LOW
Afio     = AF

Counts (port.h)

Location: boards/your_board_name/

Example 
#define PDM_TYPE 2              // 0 = PDM, 1 = PDM-MAX, 2 = your new board
#define PDM_NUM_OUTPUTS 8       // Total number of Profet outputs on your board
#define PDM_NUM_INPUTS 2        // Total number of digital inputs on your board

To Do

Setting up and using VarMap

Output Declarations (hw_devices.cpp)

Location: boards/your_board_name/

Key points: - Only modify the #if PDM_TYPE == 2 section (match your PDM_TYPE value) - Declare outputs in order: IN, DEN, DSEL, IS - &PWMD specifies the timer module (must be unique per output) - &pwmCfg references the PWM configuration (defined in port_pwm.h)

Example 
#if PDM_TYPE == 2
// Output declarations for your board
// Each output needs timer assignment and config reference
#endif

CAN/USB Message Handling (msg.cpp)

Location: common/ (root-level modification)

Update this file to transmit the status of your new outputs in both CAN and USB streams. Check existing board implementations for the pattern.

Root Makefile

Location: Makefile (repository root)

Changes needed 
ifeq ($(BOARD),)
    BOARD = your_board_name
endif

PWM Configuration (port_pwm.h)

Location: boards/your_board_name/

Steps: 1. Copy an existing PWM configuration and rename it for your board 2. Declare the .callback member for each output 3. Add callback functions in two sections: - Output PWM period callbacks – called when PWM period changes - Output PWM duty cycle callbacks – called when duty cycle changes

Example callback pattern 
static void your_board_pwm_period_callback(uint16_t value) {
    // Handle period change
}

static void your_board_pwm_duty_callback(uint16_t value) {
    // Handle duty cycle change
}

Timer Configuration (mcuconf.h)

Location: boards/your_board_name/

When needed: - Enable new timer peripherals only if your PWM configuration uses timers not already enabled - Check existing boards to see which timers are already configured - If reusing timers from the reference board, no changes needed

Build and Flash

Once all files are configured:

  • Build the firmware 

    make BOARD=your_board_name

  • Flash to your STM32

Validation Checklist

Before testing your custom board:

  • All pin definitions in board.h match your schematic
  • PDM_NUM_OUTPUTS matches your physical output count
  • PDM_NUM_INPUTS matches your physical input count
  • PDM_TYPE is unique and consistent across all files
  • All PWM timer assignments are unique (no conflicts)
  • msg.cpp includes your outputs in CAN/USB telemetry
  • .ld linker script is renamed correctly
  • Firmware builds without errors: make BOARD=your_board_name

Common Issues & Troubleshooting

Issue Cause Solution
Linker errors .ld file not renamed or path wrong Verify .ld filename matches board name exactly
Undefined PDM_TYPE Inconsistent PDM_TYPE values across files Search all files and ensure consistency
PWM conflicts Timer assigned to multiple outputs Review hw_devices.cpp and use unique timers
Build fails: unknown board Root Makefile not updated Add board to ifeq block in root Makefile
Outputs not responding Wrong pin configuration Double-check board.h pin modes and alternate functions

Reference: File Structure

DingoPDM_FW/
├── Makefile
├── boards/
│   ├── existing_board_1/
│   │   ├── board.c
│   │   ├── board.h
│   │   ├── board.mk
│   │   ├── board_name.ld
│   │   ├── hw_devices.cpp
│   │   ├── mcuconf.h
│   │   ├── port.h
│   │   └── port_pwm.h
│   └── your_board_name/          ← Copy here
│       ├── board.c
│       ├── board.h
│       ├── board.mk
│       ├── your_board_name.ld
│       ├── hw_devices.cpp
│       ├── mcuconf.h
│       ├── port.h
│       └── port_pwm.h
└── common/
    ├── msg.cpp                    ← Update here
    └── ...

Next Steps

After building and flashing:

  • Verify all outputs turn on/off correctly
  • Monitor current feedback (IS) pins via CAN/USB telemetry
  • Test PWM duty cycle control on IN pins
  • Validate multiplexing on DSEL (BTS7008-2EPP only)

For questions, refer to the main dingoPDM GitHub repository

Note

Thanks to jabbarider for this write up