initial commit

This commit is contained in:
sid 2026-05-13 18:23:02 +02:00
commit 823f030974
8 changed files with 461 additions and 0 deletions

1
.envrc Normal file
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use flake

5
.gitignore vendored Normal file
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.cache/
.direnv/
build/
compile_commands.json
result

67
Makefile Normal file
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PREFIX ?= arm-none-eabi-
CC = $(PREFIX)gcc
OBJCOPY = $(PREFIX)objcopy
SIZE = $(PREFIX)size
PNAME := bincnt
BUILD := build
# libopencm3 is provided by the Nix shell
OPENCM3_DIR ?= ""
SRCS := src/main.c
OBJS := $(addprefix $(BUILD)/, $(SRCS:.c=.o))
# STM32G4
CPU_FLAGS := -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -mfpu=fpv4-sp-d16
CFLAGS := $(CPU_FLAGS) \
-DSTM32G4 \
-Os -Wall -Wextra \
-ffunction-sections -fdata-sections \
-I$(OPENCM3_DIR)/include
LDFLAGS := $(CPU_FLAGS) \
-nostartfiles \
-Wl,--gc-sections \
-L$(OPENCM3_DIR)/lib \
-lopencm3_stm32g4
ELF := $(BUILD)/$(PNAME).elf
BIN := $(BUILD)/$(PNAME).bin
HEX := $(BUILD)/$(PNAME).hex
.PHONY: all clean flash size
all: $(BIN) $(HEX) size
$(BUILD)/%.o: %.c
@mkdir -p $(@D)
$(CC) $(CFLAGS) -c $< -o $@
LDSCRIPT := $(BUILD)/stm32g474xe.ld
$(LDSCRIPT):
@mkdir -p $(@D)
$(CC) -I$(OPENCM3_DIR)/include $(shell python3 $(OPENCM3_DIR)/scripts/genlink.py $(OPENCM3_DIR)/ld/devices.data stm32g474xe DEFS) -P -E $(OPENCM3_DIR)/ld/linker.ld.S -o $@
$(ELF): $(OBJS) $(LDSCRIPT)
$(CC) $(OBJS) $(LDFLAGS) -T$(LDSCRIPT) -o $@
$(BIN): $(ELF)
$(OBJCOPY) -O binary $< $@
$(HEX): $(ELF)
$(OBJCOPY) -O ihex $< $@
size: $(ELF)
$(SIZE) $<
flash: $(BIN)
openocd \
-f interface/stlink.cfg \
-f target/stm32g4x.cfg \
-c "program $(BIN) verify reset exit 0x08000000"
clean:
rm -rf $(BUILD)

1
README.md Normal file
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Binary counter on status LEDs `LED_OR`, `LED_GR`, and `LED_RD` using [libopencm3](https://github.com/libopencm3/libopencm3).

6
build.sh Normal file
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#!/usr/bin/env bash
set -euo pipefail
make clean
mkdir -p build
bear -- make

137
flake.lock generated Normal file
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{
"nodes": {
"flake-compat": {
"flake": false,
"locked": {
"lastModified": 1767039857,
"narHash": "sha256-vNpUSpF5Nuw8xvDLj2KCwwksIbjua2LZCqhV1LNRDns=",
"owner": "NixOS",
"repo": "flake-compat",
"rev": "5edf11c44bc78a0d334f6334cdaf7d60d732daab",
"type": "github"
},
"original": {
"owner": "NixOS",
"repo": "flake-compat",
"type": "github"
}
},
"gitignore": {
"inputs": {
"nixpkgs": [
"pre-commit-hooks",
"nixpkgs"
]
},
"locked": {
"lastModified": 1709087332,
"narHash": "sha256-HG2cCnktfHsKV0s4XW83gU3F57gaTljL9KNSuG6bnQs=",
"owner": "hercules-ci",
"repo": "gitignore.nix",
"rev": "637db329424fd7e46cf4185293b9cc8c88c95394",
"type": "github"
},
"original": {
"owner": "hercules-ci",
"repo": "gitignore.nix",
"type": "github"
}
},
"libopencm3-src": {
"flake": false,
"locked": {
"lastModified": 1776882709,
"narHash": "sha256-P1MauqEzbra2asJf1uMU/7tUeAfYzYbyDltmbm86SLU=",
"owner": "libopencm3",
"repo": "libopencm3",
"rev": "fe769eef14a7930089d1cd729834facd589f5eee",
"type": "github"
},
"original": {
"owner": "libopencm3",
"repo": "libopencm3",
"type": "github"
}
},
"nixpkgs": {
"locked": {
"lastModified": 1778124196,
"narHash": "sha256-pYEytCNic/czazbV9r3tbQ6BZzqRBg/41x2dIC5ymOo=",
"owner": "NixOS",
"repo": "nixpkgs",
"rev": "68a8af93ff4297686cb68880845e61e5e2e41d92",
"type": "github"
},
"original": {
"id": "nixpkgs",
"ref": "nixpkgs-unstable",
"type": "indirect"
}
},
"pre-commit-hooks": {
"inputs": {
"flake-compat": "flake-compat",
"gitignore": "gitignore",
"nixpkgs": [
"nixpkgs"
]
},
"locked": {
"lastModified": 1776796298,
"narHash": "sha256-PcRvlWayisPSjd0UcRQbhG8Oqw78AcPE6x872cPRHN8=",
"owner": "cachix",
"repo": "pre-commit-hooks.nix",
"rev": "3cfd774b0a530725a077e17354fbdb87ea1c4aad",
"type": "github"
},
"original": {
"owner": "cachix",
"repo": "pre-commit-hooks.nix",
"type": "github"
}
},
"root": {
"inputs": {
"libopencm3-src": "libopencm3-src",
"nixpkgs": "nixpkgs",
"pre-commit-hooks": "pre-commit-hooks",
"utils": "utils"
}
},
"systems": {
"locked": {
"lastModified": 1681028828,
"narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
"owner": "nix-systems",
"repo": "default",
"rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
"type": "github"
},
"original": {
"owner": "nix-systems",
"repo": "default",
"type": "github"
}
},
"utils": {
"inputs": {
"systems": "systems"
},
"locked": {
"lastModified": 1731533236,
"narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
"owner": "numtide",
"repo": "flake-utils",
"rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
"type": "github"
},
"original": {
"owner": "numtide",
"repo": "flake-utils",
"type": "github"
}
}
},
"root": "root",
"version": 7
}

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flake.nix Normal file
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{
inputs = {
nixpkgs.url = "nixpkgs/nixpkgs-unstable";
utils.url = "github:numtide/flake-utils";
libopencm3-src = {
url = "github:libopencm3/libopencm3";
flake = false;
};
pre-commit-hooks = {
url = "github:cachix/pre-commit-hooks.nix";
inputs.nixpkgs.follows = "nixpkgs";
};
};
outputs =
{
self,
nixpkgs,
utils,
libopencm3-src,
pre-commit-hooks,
...
}:
{
overlays.default = final: prev: {
libopencm3-stm32g4 = final.stdenvNoCC.mkDerivation {
pname = "libopencm3-stm32g4";
version = "latest";
src = libopencm3-src;
postPatch = ''
patchShebangs scripts
'';
nativeBuildInputs = [
final.gcc-arm-embedded
final.python3
final.gnumake
];
enableParallelBuilding = true;
makeFlags = [
"PREFIX=arm-none-eabi-"
];
TARGETS = "stm32/g4";
installPhase = ''
runHook preInstall
mkdir -p $out
cp -r include lib mk scripts ld $out/
patchShebangs $out/scripts
runHook postInstall
'';
meta = with final.lib; {
description = "Open source ARM Cortex-M microcontroller library (STM32G4 target)";
homepage = "http://libopencm3.org/";
license = licenses.lgpl3Plus;
platforms = platforms.all;
};
};
};
}
// utils.lib.eachDefaultSystem (
system:
let
pkgs = import nixpkgs {
inherit system;
overlays = [ self.overlays.default ];
};
pname = "bincnt";
version = "0.1.0";
in
{
packages = {
inherit (pkgs) libopencm3-stm32g4;
default = pkgs.stdenvNoCC.mkDerivation {
inherit pname version;
src = pkgs.lib.cleanSource ./.;
nativeBuildInputs = with pkgs; [
gcc-arm-embedded
gnumake
python3
];
makeFlags = [
"OPENCM3_DIR=${pkgs.libopencm3-stm32g4}"
"PREFIX=arm-none-eabi-"
];
installPhase = ''
runHook preInstall
mkdir -p $out/bin
cp build/${pname}.elf $out/bin/
cp build/${pname}.bin $out/bin/
cp build/${pname}.hex $out/bin/
runHook postInstall
'';
};
};
devShells.default =
let
# FIXME: 'gnu/stubs-32.h' file not found
clangdWrapper = pkgs.writeShellScriptBin "clangd" ''
exec ${pkgs.clang-tools}/bin/clangd \
--query-driver=${pkgs.gcc-arm-embedded}/bin/arm-none-eabi-* \
"$@"
'';
in
pkgs.mkShell {
name = "stm32-blink";
packages = self.packages.${system}.default.nativeBuildInputs ++ [
clangdWrapper
pkgs.bear
pkgs.openocd
pkgs.stlink
];
OPENCM3_DIR = pkgs.libopencm3-stm32g4;
PREFIX = "arm-none-eabi-";
};
formatter =
let
inherit (self.checks.${system}.pre-commit-check.config) package configFile;
script = ''
${pkgs.lib.getExe package} run --all-files --config ${configFile}
'';
in
pkgs.writeShellScriptBin "pre-commit-run" script;
checks = {
build-packages = pkgs.linkFarm "flake-packages-${system}" self.packages.${system};
pre-commit-check = pre-commit-hooks.lib.${system}.run {
src = ./.;
hooks = {
nixfmt.enable = true;
clang-format = {
enable = true;
types_or = pkgs.lib.mkForce [
"c"
"c++"
];
};
};
};
};
}
);
}

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#include <libopencm3/cm3/systick.h>
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/rcc.h>
#define LED_OR_PORT GPIOC
#define LED_OR_PIN GPIO10
#define LED_GR_PORT GPIOC
#define LED_GR_PIN GPIO11
#define LED_RD_PORT GPIOC
#define LED_RD_PIN GPIO12
#define COUNT_PERIOD_MS 500
static volatile uint32_t s_ticks = 0;
void sys_tick_handler(void) { s_ticks++; }
static void delay_ms(uint32_t ms) {
uint32_t until = s_ticks + ms;
while (s_ticks < until)
;
}
static void clock_setup(void) {
rcc_clock_setup_pll(&rcc_hsi_configs[RCC_CLOCK_3V3_170MHZ]);
}
static void systick_setup(void) {
/* 1 ms tick at 170 MHz core clock */
systick_set_reload(rcc_ahb_frequency / 1000 - 1);
systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
systick_counter_enable();
systick_interrupt_enable();
}
static void gpio_setup(void) {
rcc_periph_clock_enable(RCC_GPIOC);
gpio_mode_setup(LED_OR_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, LED_OR_PIN);
gpio_mode_setup(LED_GR_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, LED_GR_PIN);
gpio_mode_setup(LED_RD_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, LED_RD_PIN);
gpio_set_output_options(LED_OR_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_LOW,
LED_OR_PIN);
gpio_set_output_options(LED_GR_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_LOW,
LED_GR_PIN);
gpio_set_output_options(LED_RD_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_LOW,
LED_RD_PIN);
gpio_clear(LED_OR_PORT, LED_OR_PIN);
gpio_clear(LED_GR_PORT, LED_GR_PIN);
gpio_set(LED_RD_PORT, LED_RD_PIN); // active low
}
static void gpio_write(uint32_t gpioport, uint16_t gpios, uint8_t value) {
if (value == 0) {
gpio_clear(gpioport, gpios);
} else {
gpio_set(gpioport, gpios);
}
}
static void set_binary_counter(uint8_t value) {
gpio_write(LED_OR_PORT, LED_OR_PIN, value & 0x04);
gpio_write(LED_GR_PORT, LED_GR_PIN, value & 0x02);
gpio_write(LED_RD_PORT, LED_RD_PIN, value & 0x01);
}
int main(void) {
clock_setup();
systick_setup();
gpio_setup();
uint8_t counter = 0;
while (1) {
set_binary_counter(counter);
delay_ms(COUNT_PERIOD_MS);
counter++; // overflow is fine
}
return 0;
}