STM32F1 CMake template for Panda Rev1

Open this folder in CLion and build the current project target, stm32f1-test. The target is STM32F103C8T6, Cortex-M3, 64 KB Flash / 20 KB RAM, running from the internal 8 MHz HSI.

The current main.c initializes the clock, and initializes USART1. It then waits for an ASCII character:

Input	USART reply
1	Hello\r\n
2	Welcome\r\n
Other characters, including Enter/CR/LF	No reply

The program waits for a recognized command before sending a reply. Follow the CLion serial connection steps below to send commands and see replies.

Folder	Contents
src/	Application entry point, main.c
Drivers/Gpio/, Drivers/Rcc/, Drivers/Usart/	Custom peripheral drivers
BSP/Panda/	Board pin definitions
Lib/	Shared types, bit operations and optional utilities
cmake/	Tool paths, device mapping, build and programming rules
debug/	OpenOCD configuration and manual GDB scripts

STM32-base supplies the reset handler and vector table.

Included dependencies

The dependencies are checked in: configuring/building needs no downloads. Only STM32F1 startup, linker, device and HAL files are included, together with the shared startup/linker files and ARM CMSIS headers.

STM32F103x8.ld provides the C8 memory layout. Its startup and CMSIS density group is STM32F103xB, so the project uses STM32F103xB.s and defines STM32F103xB. This does not increase the Flash allocation to 128 KB. startup_common.s and common.ld are necessary dependencies of these files.

Upstream license notices are preserved; see THIRD_PARTY.md. These vendor versions match the STM32-base ecosystem used in the F4 template; they are not the latest ST CubeF1 drivers.

Tools

• Arm GNU Toolchain, targeting arm-none-eabi; GCC, GDB, objcopy and size.
• CMake 3.30+ and Ninja; CLion bundles both.
• For the recommended flash/debug workflow: OpenOCD 0.12+, and the Windows ST-Link USB driver.
• An alternative bundle is STM32CubeCLT, which supplies the ARM tools, ST-LINK GDB server and CubeProgrammer CLI. OpenOCD is a separate tool.

The CMake layout follows the STM32F4 template: CMakeLists.txt includes ArmToolchain.cmake before project(stm32f1-test C), then loads Device.cmake, SourceList.cmake and IncludeList.cmake. Device.cmake loads MappedTarget.cmake. The executable uses ${CMAKE_PROJECT_NAME}.

Set ARM_DIR in cmake/ArmToolchain.cmake to the ARM installation directory (the folder before bin/), just as in the F4 template. ARM_TOOLCHAIN_DIR is then derived as ${ARM_DIR}/bin. You can also supply -DARM_DIR=... when configuring, or use the local user preset below. Reset the CMake cache when changing compilers or editing a previously cached toolchain path.

cmake --preset debug
cmake --build cmake-build-debug

The optional release and debug-hal presets use cmake-build-release/ and cmake-build-debug-hal/. The normal CLion Debug profile uses cmake-build-debug/. Presets no longer generate the extra build/ directory. For terminal commands, CMake and Ninja must be on PATH.

Run and debug in CLion

See README_CLION.md for the complete setup, explanations of the debug/ files, CMake profiles/presets and generated output files.

• Select Panda Run (HEX) with the ordinary host GDB profile and click Run to build, flash HEX and run the kit.
• Select Panda Debug (ELF) with your working Panda OpenOCD debug profile and click Debug to build, upload ELF and debug the kit.

CMake generates the run configurations in .run/ from cmake/clion/ templates. Changing project(...) and reloading CMake updates the names in the generated files. If CLion still shows an old Debug target, select the renamed firmware in both Target and Executable under Run > Edit Configurations. Keep your working OpenOCD debug profile: -f debug/panda-stlink.cfg, project root as working directory, upload Always, reset command monitor reset halt, and connection localhost:3333 without persistent session.

ST-Link V2 connection

Use the four-pin SWD header on the Blue Pill, not the carrier's UART port. The Panda manual, page 27, shows this pinout for the pictured USB dongle:

ST-Link signal	Blue Pill signal	MCU pin	Pictured dongle pin
SWDIO	SWIO / SWDIO	PA13	4
SWCLK	SWCLK	PA14	2
GND	GND	Ground	6
3.3 V / target reference	3V3	3.3 V rail	8

Follow signal labels on your probe; numbering varies between ST-Link versions. On the dongle pictured in the manual, 3.3 V is a power output; on official probes the corresponding target-voltage reference may be an input. Power the Panda carrier through its USB Type-B input and power switch for normal kit use. With an already powered kit and a dongle providing 3.3 V output, use SWDIO, SWCLK and common GND; do not tie two power outputs together. Connect a genuine probe's target reference as its manual requires. NRST is optional if your probe exposes a real STM32 reset signal; the supplied config uses software reset for the four-pin connector. Do not use SWIM or a 5 V pin.

Set BOOT0 = 0 for normal Flash boot. Enable the TX/RX DIP switches for the USART example. The template leaves PA13/PA14 assigned to SWD.

Send and receive USART commands

First build and flash the current firmware with Panda Run (HEX). If using Panda Debug (ELF), resume the MCU so it can execute the receive loop.

To use it inside CLion:

1. Connect the Panda's USB Type-B to your computer with a data cable, power the kit, and enable TX/RX DIP switches.
2. Install Serial Port Monitor under Settings → Plugins if needed.
3. Open View → Tool Windows → Serial Connections. JetBrains instructions.
4. Select the CH340 COM port. Find its number in Windows Device Manager → Ports (COM & LPT). Install the CH340 driver if no COM port appears.
5. Set 9600 baud, 8 data bits, no parity, 1 stop bit, no flow control, then Connect. Use text/ASCII mode; local echo can be off.
6. Send text 1 or 2: 1 replies with Hello, and 2 replies with Welcome. Both replies end with a new line. Use the terminal's Send action or Enter if it buffers typed input.

Input:  Computer → USB → CH340 → PA10 (USART1 RX)
Output: PA9 (USART1 TX) → CH340 → USB → Computer

Type commands and read replies in Serial Connections. The normal CLion Run console displays build/debug logs. The serial window stays quiet until you send a recognized command.

The commands are ASCII digits ('1' / '2'), not binary bytes 0x01 / 0x02. Wait for each reply before sending the next command. This is a simple polling driver with no interrupt/DMA receive queue; long pasted bursts can overrun it.

Rcc_Init selects HSI at 8 MHz and sets both APB prescalers to divide by one. USART1's PCLK2 is therefore 8 MHz. Usart1_Init configures TX as alternate- function push-pull and RX as an input with pull-up; STM32F1 has no F4-style AF7 pin selection. Its rounded baud divider is BRR = 833 (0x341) for 9600 baud. Update the divider if you change the APB2 clock or the baud rate.

Flash/debug from a terminal

Set OPENOCD_BIN_DIR to your installed OpenOCD bin/ directory at the top of cmake/Programming.cmake. Each developer supplies their own paths; the project does not search PATH or scan installation directories. OPENOCD_EXECUTABLE is derived as ${OPENOCD_BIN_DIR}/openocd${Extension}. An existing executable enables flash and debug-server. flash programs the HEX and exits. These path settings use the CMake cache, like ARM_DIR: reset the cache and reload after editing a previously configured path, or override it with -DOPENOCD_BIN_DIR=C:/path/to/openocd/bin. If OpenOCD cannot locate its bundled scripts, also configure with -DOPENOCD_SCRIPTS_DIR=C:/path/to/openocd/scripts. Both programming targets build the firmware first. debug-server also programs/verifies the ELF and halts the MCU, then keeps OpenOCD running for GDB.

cmake --build cmake-build-debug --target flash

# Terminal 1: stays running until stopped with Ctrl+C.
cmake --build cmake-build-debug --target debug-server

# Terminal 2: attach to the already programmed MCU and set a main breakpoint.
arm-none-eabi-gdb cmake-build-debug/stm32f1-test.elf -x debug/panda-attach.gdb
# In GDB: continue

Optionally set STM32_PROGRAMMER_CLI in cmake/Programming.cmake to its full installed path. It enables flash-st, which programs/verifies/resets the ELF through ST-Link. Leave it empty when using only OpenOCD. A command-line override is also supported:

cmake --preset debug '-DSTM32_PROGRAMMER_CLI=C:/path/to/STM32_Programmer_CLI.exe'
cmake --build cmake-build-debug --target flash-st

Programming replaces existing kit firmware, including the factory demo.

Panda peripheral map

From the manual's schematics and pin tables (pages 10-24):

Peripheral	Pins / notes
Red1, Red2, Green	PA2, PA1, PC15; active high, individual DIP switches
Blue, Yellow	PC14, PC13; active high, individual DIP switches
Buzzer	PB4; release this JTAG pin while keeping SWD before use
Relay1, Relay2	PB5, PA3
Analog potentiometer	PA0
USART1 / CH340	PA9 TX, PA10 RX; enable TX/RX DIP switches
Keypad columns 1-4	PB11, PB10, PB1, PB0; active-low inputs with pull-ups
Keypad rows 1-4	PA4, PA5, PA6, PA7; select MATRIX mode for all 16 keys
LCD RS, EN, D4-D7	PA11, PA8, PB15, PB14, PB13, PB12
Seven-segment A, B, C, D, E, F, G, DOT	PA11, PA8, PB15, PB14, PB13, PB12, PA12, PA15
Seven-segment COM1, COM2, COM3	PB8, PB9, PB3
OLED	SCL PB6, SDA PB7, as drawn on page 22 and labeled on the PCB

Manual inconsistencies: the general-output prose on page 16 lists different pins from the schematic and PCB photo on page 15. The template follows the schematic/photo: Red1 is PA2, Red2 PA1, Green PC15, Blue PC14, Yellow PC13, Buzzer PB4, Relay1 PB5 and Relay2 PA3. Check your PCB labels if the kit revision differs. The Blue Pill's own PC13 LED may also respond when driving Yellow. Green/Blue conflict with an enabled LSE crystal on PC15/PC14.

The OLED table on page 21 reverses SCL/SDA relative to the schematic/photo; confirm the board revision before writing its driver. LCD and seven-segment share pins: disable the other display's DIP switches. PA11/PA12 overlap USB. PB3/PB4/PA15 default to JTAG: disable JTAG only, keeping SWD when using them (__HAL_AFIO_REMAP_SWJ_NOJTAG() with HAL and the AFIO clock enabled). The USART1 example uses the default PA9/PA10 mapping and needs no USART remapping.

The carrier's USB Type-B connects to CH340 UART, not MCU USB debugging. Use that COM port with your serial terminal for this example's USART1 commands.