stm32 examples revamp

2026-11-06 15:51:25 +00:00 · 2026-05-22 15:39:25 +01:00
1 parent d4013e47f9
commit 21b9cdaef7
@@ -0,0 +1,50 @@
+# Copyright (c) 2026 Cesanta Software Limited
+# Environment setup: https://mongoose.ws/docs/getting-started/build-environment/
+
+CFLAGS  = -W -Wall -Wextra -Werror -Wundef -Wshadow -Wdouble-promotion
+CFLAGS += -Wformat-truncation -fno-common -Wconversion -Wno-sign-conversion
+CFLAGS += -g3 -Os -ffunction-sections -fdata-sections
+CFLAGS += -I. -Icmsis_core/CMSIS/Core/Include -Icmsis_g0/Include -Imongoose
+CFLAGS += -mcpu=cortex-m0 -mthumb -mfloat-abi=soft $(CFLAGS_EXTRA)
+LDFLAGS ?= -Tlink.ld -nostdlib -nostartfiles --specs nano.specs -lc -lgcc -Wl,--gc-sections -Wl,-Map=$@.map
+
+SOURCES = main.c hal.c
+SOURCES += cmsis_g0/Source/Templates/gcc/startup_stm32g031xx.s
+SOURCES += mongoose/mongoose.c
+
+CFLAGS += -DHTTP_URL=\"http://0.0.0.0/\"
+
+all build example: firmware.bin
+
+mongoose/mongoose.c mongoose/mongoose.h:
+	cp ../../../../mongoose.[ch] mongoose/
+
+firmware.elf: cmsis_core cmsis_g0 hal.h link.ld Makefile $(SOURCES) mongoose/mongoose.h
+	arm-none-eabi-gcc $(SOURCES) $(CFLAGS) $(CFLAGS_EXTRA) $(LDFLAGS) -o $@
+
+firmware.bin: firmware.elf
+	arm-none-eabi-objcopy -O binary $< $@
+	@echo
+	@echo "To flash, run 'make flash'"
+
+flash: firmware.bin
+	st-flash --reset write $< 0x8000000
+
+cmsis_core:
+	git clone -q -c advice.detachedHead=false --depth 1 -b 5.9.0 https://github.com/ARM-software/CMSIS_5 $@
+
+cmsis_g0:
+	git clone -q -c advice.detachedHead=false --depth 1 -b v1.4.3 https://github.com/STMicroelectronics/cmsis_device_g0 $@
+
+clean:
+	rm -rf firmware.* cmsis_* mongoose/mongoose.*
+
+# Automated remote test. Requires env variable VCON_API_KEY set. See https://vcon.io/automated-firmware-tests/
+DEVICE_URL ?= https://dash.vcon.io/api/v3/devices/10
+update: firmware.bin
+	curl --fail-with-body -su :$(VCON_API_KEY) $(DEVICE_URL)/ota --data-binary @$<
+
+test update: CFLAGS_EXTRA = -DUART_DEBUG=USART1
+test: update
+	curl --fail-with-body -su :$(VCON_API_KEY) $(DEVICE_URL)/tx?t=5 | tee /tmp/output.txt
+	grep 'READY, IP:' /tmp/output.txt       # Check for network init
@@ -0,0 +1,120 @@
+// Copyright (c) 2026 Cesanta Software Limited
+// All rights reserved
+
+#include "hal.h"
+
+bool hal_timer_expired(volatile uint64_t *t, uint64_t period, uint64_t now) {
+  uint64_t diff = now - *t;         // Wrap-safe elapsed time since last expiry
+  if (period == 0) return false;    // Avoid division by zero
+  if (diff < period) return false;  // Period has not elapsed yet
+  *t += (diff / period) * period;   // Preserve cadence, skip missed periods
+  return true;
+}
+
+static volatile uint64_t s_ticks;  // Milliseconds since boot
+void SysTick_Handler(void) {       // SyStick IRQ handler, triggered every 1ms
+  s_ticks++;
+}
+
+uint64_t hal_get_tick(void) {
+  return s_ticks;
+}
+
+uint32_t SystemCoreClock = CPU_FREQUENCY;
+void SystemInit(void) {  // Called automatically by startup code
+  rng_init();
+  SysTick_Config(CPU_FREQUENCY / 1000);  // Sys tick every 1ms
+}
+
+struct stat;
+__attribute__((weak)) int _fstat(int fd, struct stat *st) {
+  (void) fd, (void) st;
+  return -1;
+}
+
+extern unsigned char _end[];  // End of data section, start of heap. See link.ld
+static unsigned char *s_current_heap_end = _end;
+
+size_t hal_ram_used(void) {
+  return (size_t) (s_current_heap_end - _end);
+}
+
+size_t hal_ram_free(void) {
+  unsigned char endofstack;
+  return (size_t) (&endofstack - s_current_heap_end);
+}
+
+void *_sbrk(int incr) {
+  unsigned char *prev_heap;
+  unsigned char *heap_end = (unsigned char *) ((size_t) &heap_end - 256);
+  prev_heap = s_current_heap_end;
+  if (s_current_heap_end + incr > heap_end) return (void *) -1;
+  s_current_heap_end += incr;
+  return prev_heap;
+}
+
+__attribute__((weak)) int _open(const char *path) {
+  (void) path;
+  return -1;
+}
+
+__attribute__((weak)) int _close(int fd) {
+  (void) fd;
+  return -1;
+}
+
+__attribute__((weak)) int _isatty(int fd) {
+  (void) fd;
+  return 1;
+}
+
+__attribute__((weak)) int _lseek(int fd, int ptr, int dir) {
+  (void) fd, (void) ptr, (void) dir;
+  return 0;
+}
+
+__attribute__((weak)) void _exit(int status) {
+  (void) status;
+  for (;;) asm volatile("BKPT #0");
+}
+
+__attribute__((weak)) void _kill(int pid, int sig) {
+  (void) pid, (void) sig;
+}
+
+__attribute__((weak)) int _getpid(void) {
+  return -1;
+}
+
+__attribute__((weak)) int _write(int fd, char *ptr, int len) {
+  (void) fd, (void) ptr, (void) len;
+  return -1;
+}
+
+__attribute__((weak)) int _read(int fd, char *ptr, int len) {
+  (void) fd, (void) ptr, (void) len;
+  return -1;
+}
+
+__attribute__((weak)) int _link(const char *a, const char *b) {
+  (void) a, (void) b;
+  return -1;
+}
+
+__attribute__((weak)) int _unlink(const char *a) {
+  (void) a;
+  return -1;
+}
+
+__attribute__((weak)) int _stat(const char *path, struct stat *st) {
+  (void) path, (void) st;
+  return -1;
+}
+
+__attribute__((weak)) int mkdir(const char *path, int mode) {
+  (void) path, (void) mode;
+  return -1;
+}
+
+__attribute__((weak)) void _init(void) {
+}
@@ -0,0 +1,195 @@
+// Copyright (c) 2022-2023 Cesanta Software Limited
+// All rights reserved
+//
+// MCU manual: RM0444, board manual: UM2591
+// https://www.st.com/resource/en/reference_manual/rm0444-stm32g0x1-advanced-armbased-32bit-mcus-stmicroelectronics.pdf
+// https://www.st.com/resource/en/user_manual/um2591-stm32g0-nucleo32-board-mb1455-stmicroelectronics.pdf
+// Alternate functions: https://www.st.com/resource/en/datasheet/stm32g031c6.pdf
+
+#pragma once
+
+// #define LED PIN('B', 3)
+#define LED PIN('C', 6)
+
+#include <stm32g031xx.h>
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+extern bool hal_timer_expired(volatile uint64_t *t, uint64_t prd, uint64_t now);
+extern uint64_t hal_get_tick(void);
+extern size_t hal_ram_free(void);
+extern size_t hal_ram_used(void);
+extern uint32_t SystemCoreClock;
+
+#define BIT(x) (1UL << (x))
+#define SETBITS(R, CLEARMASK, SETMASK) (R) = ((R) & ~(CLEARMASK)) | (SETMASK)
+#define PIN(bank, num) ((((bank) - 'A') << 8) | (num))
+#define PINNO(pin) (pin & 255)
+#define PINBANK(pin) (pin >> 8)
+
+#define CPU_FREQUENCY 16000000
+#define AHB_FREQUENCY CPU_FREQUENCY
+#define APB_FREQUENCY CPU_FREQUENCY
+// #define APB1_FREQUENCY (AHB_FREQUENCY / (BIT(PPRE1 - 3)))
+
+static inline void spin(volatile uint32_t n) {
+  while (n--) (void) 0;
+}
+
+enum { GPIO_MODE_INPUT, GPIO_MODE_OUTPUT, GPIO_MODE_AF, GPIO_MODE_ANALOG };
+enum { GPIO_OTYPE_PUSH_PULL, GPIO_OTYPE_OPEN_DRAIN };
+enum { GPIO_SPEED_LOW, GPIO_SPEED_MEDIUM, GPIO_SPEED_HIGH, GPIO_SPEED_INSANE };
+enum { GPIO_PULL_NONE, GPIO_PULL_UP, GPIO_PULL_DOWN };
+
+#define GPIO(N) ((GPIO_TypeDef *) ((GPIOA_BASE) + 0x400 * (N)))
+
+static GPIO_TypeDef *gpio_bank(uint16_t pin) {
+  return GPIO(PINBANK(pin));
+}
+static inline void gpio_toggle(uint16_t pin) {
+  GPIO_TypeDef *gpio = gpio_bank(pin);
+  uint32_t mask = BIT(PINNO(pin));
+  gpio->BSRR = mask << (gpio->ODR & mask ? 16 : 0);
+}
+static inline int gpio_read(uint16_t pin) {
+  return gpio_bank(pin)->IDR & BIT(PINNO(pin)) ? 1 : 0;
+}
+static inline void gpio_write(uint16_t pin, bool val) {
+  GPIO_TypeDef *gpio = gpio_bank(pin);
+  gpio->BSRR = BIT(PINNO(pin)) << (val ? 0 : 16);
+}
+static inline void gpio_init(uint16_t pin, uint8_t mode, uint8_t type,
+                             uint8_t speed, uint8_t pull, uint8_t af) {
+  GPIO_TypeDef *gpio = gpio_bank(pin);
+  uint8_t n = (uint8_t) (PINNO(pin));
+  RCC->IOPENR |= BIT(PINBANK(pin));  // Enable GPIO clock
+  SETBITS(gpio->OTYPER, 1UL << n, ((uint32_t) type) << n);
+  SETBITS(gpio->OSPEEDR, 3UL << (n * 2), ((uint32_t) speed) << (n * 2));
+  SETBITS(gpio->PUPDR, 3UL << (n * 2), ((uint32_t) pull) << (n * 2));
+  SETBITS(gpio->AFR[n >> 3], 15UL << ((n & 7) * 4),
+          ((uint32_t) af) << ((n & 7) * 4));
+  SETBITS(gpio->MODER, 3UL << (n * 2), ((uint32_t) mode) << (n * 2));
+}
+static inline void gpio_input(uint16_t pin) {
+  gpio_init(pin, GPIO_MODE_INPUT, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH,
+            GPIO_PULL_NONE, 0);
+}
+static inline void gpio_output(uint16_t pin) {
+  gpio_init(pin, GPIO_MODE_OUTPUT, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH,
+            GPIO_PULL_NONE, 0);
+}
+
+static inline bool uart_init(USART_TypeDef *uart, uint16_t tx, uint16_t rx,
+                             unsigned long baud) {
+  uint8_t af = 1;           // Alternate function
+  uint32_t freq = 0;        // Bus frequency
+
+  if (uart == USART1) {
+    freq = CPU_FREQUENCY, RCC->APBENR2 |= RCC_APBENR2_USART1EN;
+  } else if (uart == USART2) {
+    freq = CPU_FREQUENCY, RCC->APBENR1 |= RCC_APBENR1_USART2EN;
+  } else {
+    return false;
+  }
+  gpio_init(tx, GPIO_MODE_AF, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH, 0, af);
+  gpio_init(rx, GPIO_MODE_AF, GPIO_OTYPE_PUSH_PULL, GPIO_SPEED_HIGH, 0, af);
+  uart->CR1 = 0;                            // Disable UART
+  uart->BRR = freq / baud;                  // Set baud rate
+  uart->CR1 = USART_CR1_RE | USART_CR1_TE;  // Set mode to TX & RX
+  uart->CR1 |= USART_CR1_UE;                // Enable UART
+  return true;
+}
+static inline void uart_write_byte(USART_TypeDef *uart, uint8_t byte) {
+  uart->TDR = byte;
+  while ((uart->ISR & BIT(7)) == 0) spin(1);
+}
+static inline void uart_write_buf(USART_TypeDef *uart, char *buf, size_t len) {
+  while (len-- > 0) uart_write_byte(uart, *(uint8_t *) buf++);
+}
+static inline int uart_read_ready(USART_TypeDef *uart) {
+  return uart->ISR & BIT(5);  // If RXNE bit is set, data is ready
+}
+static inline uint8_t uart_read_byte(USART_TypeDef *uart) {
+  return (uint8_t) (uart->RDR & 255);
+}
+
+#ifndef RNG
+struct rng {
+  volatile uint32_t CR, SR, DR;
+};
+#define RNG ((struct rng *) 0x40025000)  // RM0444  2.2.2  Table 6
+#endif
+
+static inline void rng_init(void) {
+  RCC->CCIPR |= 2U << 26U; // RNG clock source. Documented in 5.4.21
+  RCC->AHBENR |= BIT(18);  // RM0444 5.4.25 Table 36
+  RNG->CR |= BIT(2);       // 19.7.1
+}
+static inline uint32_t rng_read(void) {
+  while ((RNG->SR & BIT(0)) == 0) (void) 0;
+  return RNG->DR;
+}
+
+// Bit-bang SPI implementation
+struct spi {
+  uint16_t miso, mosi, clk, cs;  // Pins
+  int spin;                      // Number of NOP spins for bitbanging
+};
+
+static inline void spi_begin(struct spi *spi) {
+  gpio_write(spi->cs, 0);
+  // printf("%s\n", __func__);
+}
+
+static inline void spi_end(struct spi *spi) {
+  gpio_write(spi->cs, 1);
+  // printf("%s\n", __func__);
+}
+
+static inline void spi_init(struct spi *spi) {
+  gpio_input(spi->miso);
+  gpio_output(spi->mosi);
+  gpio_output(spi->clk);
+  gpio_output(spi->cs);
+  gpio_write(spi->cs, 1);
+  // printf("%s\n", __func__);
+}
+
+// Send a byte, and return a received byte
+static inline uint8_t spi_1byte(struct spi *spi, uint8_t write_byte) {
+  unsigned count = spi->spin <= 0 ? 9 : (unsigned) spi->spin;
+  uint8_t rx = 0, tx = write_byte;
+  for (int i = 0; i < 8; i++) {
+    gpio_write(spi->mosi, tx & 0x80U);   // Set mosi
+    gpio_write(spi->clk, 1);             // Clock high
+    spin(count);                         // Wait half cycle
+    rx <<= 1U;                           // Shift alreay read bits
+    if (gpio_read(spi->miso)) rx |= 1U;  // Read next bit
+    gpio_write(spi->clk, 0);             // Clock low
+    spin(count);                         // Wait half cycle
+    tx <<= 1U;                           // Discard written bit
+  }
+  // printf("%s %02x %02x\n", __func__, (int) write_byte, (int) rx);
+  return rx;  // Return the received byte
+}
+
+static inline void spi_txn(struct spi *spi, uint8_t *w, uint8_t *r, size_t n) {
+  while (n--) {
+    uint8_t c = (w != NULL) ? *w++ : 0xFF;
+    uint8_t d = spi_1byte(spi, c);
+    if (r != NULL) *r++ = d;
+  }       
+}
+
+#define UUID ((uint32_t *) UID_BASE)  // Unique 96-bit chip ID. TRM 59.1
+
+// Helper macro for MAC generation, byte reads not allowed
+#define GENERATE_LOCALLY_ADMINISTERED_MAC()                         \
+  {                                                                 \
+    2, UUID[0] & 255, (UUID[0] >> 10) & 255, (UUID[0] >> 19) & 255, \
+        UUID[1] & 255, UUID[2] & 255                                \
+  }
@@ -0,0 +1,30 @@
+ENTRY(Reset_Handler);
+MEMORY {
+  flash(rx) : ORIGIN = 0x08000000, LENGTH = 64k
+  sram(rwx) : ORIGIN = 0x20000000, LENGTH = 8k 
+}
+_estack = ORIGIN(sram) + LENGTH(sram);    /* End of RAM. stack points here */
+
+SECTIONS {
+  .vectors  : { KEEP(*(.isr_vector)) }  > flash
+  .text     : { *(.text* .text.*) }     > flash
+  .rodata   : { *(.rodata*) }           > flash
+
+  .data : {
+    _sdata = .;
+    *(.first_data)
+    *(.ram)
+    *(.data SORT(.data.*))
+    _edata = .;
+  } > sram AT > flash
+  _sidata = LOADADDR(.data);
+
+  .bss : {
+    _sbss = .;
+    *(.bss SORT(.bss.*) COMMON)
+    _ebss = .;
+  } > sram
+
+  . = ALIGN(8);
+  _end = .;
+}
@@ -0,0 +1,117 @@
+// Copyright (c) 2023 Cesanta Software Limited
+// All rights reserved
+
+#include "hal.h"
+#include "mongoose.h"
+
+#ifndef UART_DEBUG
+#define UART_DEBUG USART2
+#define UART_DEBUG_TX_PIN PIN('A', 2)
+#define UART_DEBUG_RX_PIN PIN('A', 3)
+#else
+#define UART_DEBUG_TX_PIN PIN('A', 9)
+#define UART_DEBUG_RX_PIN PIN('A', 10)
+#endif
+
+#define BLINK_PERIOD_MS 1000  // LED blinking period in millis
+static struct spi spi_pins = {
+    .miso = PIN('B', 4),
+    .mosi = PIN('A', 0),
+    .clk = PIN('A', 1),
+    .cs = PIN('A', 4),
+};
+
+// Redirect stdout debug output to UART
+int _write(int fd, char *ptr, int len) {
+  if (fd == 1 || fd == 2) uart_write_buf(UART_DEBUG, ptr, (size_t) len);
+  return len;
+}
+
+bool mg_random(void *buf, size_t len) {  // Use on-board RNG
+  for (size_t n = 0; n < len; n += sizeof(uint32_t)) {
+    uint32_t r = rng_read();
+    memcpy((char *) buf + n, &r, n + sizeof(r) > len ? len - n : sizeof(r));
+  }
+  return true;
+}
+
+uint64_t mg_millis(void) {
+  return hal_get_tick();
+}
+
+static void timer_fn(void *arg) {
+  gpio_toggle(LED);               // Blink LED
+  struct mg_tcpip_if *ifp = arg;  // And show
+  MG_INFO(("Ethernet: %d, IP: %M, rx:%u, tx:%u, dr:%u, er:%u", ifp->state,
+           mg_print_ip4, &ifp->ip, ifp->nrecv, ifp->nsent, ifp->ndrop,
+           ifp->nerr));
+}
+
+static void fn(struct mg_connection *c, int ev, void *ev_data) {
+  struct mg_tcpip_if *ifp = (struct mg_tcpip_if *) c->fn_data;
+  if (ev == MG_EV_HTTP_MSG) {
+    struct mg_http_message *hm = (struct mg_http_message *) ev_data;
+    if (mg_match(hm->uri, mg_str("/api/hello"),
+                 NULL)) {  // Request to /api/hello
+      mg_http_reply(c, 200, "", "{%m:%u,%m:%u,%m:%u,%m:%u,%m:%u}\n",
+                    MG_ESC("eth"), ifp->state, MG_ESC("frames_received"),
+                    ifp->nrecv, MG_ESC("frames_sent"), ifp->nsent,
+                    MG_ESC("frames_dropped"), ifp->ndrop,
+                    MG_ESC("interface_errors"), ifp->nerr);
+    } else if (mg_match(hm->uri, mg_str("/"), NULL)) {  // Index page
+      mg_http_reply(
+          c, 200, "", "%s",
+          "<html><head><link rel='icon' href='data:;base64,='></head><body>"
+          "<h1>Welcome to Mongoose</h1>"
+          "See <a href=/api/hello>/api/hello</a> for REST example"
+          "</body></html>");
+    } else {  // All other URIs
+      mg_http_reply(c, 404, "", "Not Found\n");
+    }
+  }
+}
+
+int main(void) {
+  gpio_output(LED);               // Setup green LED
+  uart_init(UART_DEBUG, UART_DEBUG_TX_PIN, UART_DEBUG_RX_PIN, 115200);
+
+  // ethernet_init();                // Initialise ethernet pins
+  MG_INFO(("Starting, CPU freq %g MHz", (double) SystemCoreClock / 1000000));
+
+  struct mg_mgr mgr;        // Initialise
+  mg_mgr_init(&mgr);        // Mongoose event manager
+  mg_log_set(MG_LL_DEBUG);  // Set log level
+
+  // Initialise Mongoose network stack
+  spi_init(&spi_pins);
+  struct mg_tcpip_spi spi = {
+      .begin = (void (*)(void *)) spi_begin,
+      .end = (void (*)(void *)) spi_end,
+      .txn = (void (*)(void *, uint8_t *, uint8_t *, size_t)) spi_txn,
+      .spi = &spi_pins,
+  };
+  struct mg_tcpip_if mif = {.mac = GENERATE_LOCALLY_ADMINISTERED_MAC(),
+                            // Uncomment below for static configuration:
+                            // .ip = mg_htonl(MG_U32(192, 168, 0, 223)),
+                            // .mask = mg_htonl(MG_U32(255, 255, 255, 0)),
+                            // .gw = mg_htonl(MG_U32(192, 168, 0, 1)),
+                            .driver = &mg_tcpip_driver_w5500,
+                            .driver_data = &spi};
+  mg_tcpip_init(&mgr, &mif);
+
+  MG_INFO(("MAC: %M. Waiting for IP...", mg_print_mac, mif.mac));
+  while (mif.state != MG_TCPIP_STATE_READY) {
+    mg_mgr_poll(&mgr, 0);
+  }
+
+  MG_INFO(("Initialising application..."));
+  mg_timer_add(&mgr, BLINK_PERIOD_MS, MG_TIMER_REPEAT, timer_fn, &mif);
+  mg_http_listen(&mgr, "http://0.0.0.0:80", fn, &mif);
+
+  MG_INFO(("Starting event loop"));
+  for (;;) {
+    mg_mgr_poll(&mgr, 0);
+  }
+
+  return 0;
+}
@@ -0,0 +1,11 @@
+#pragma once
+
+// See https://mongoose.ws/documentation/#build-options
+#define MG_ARCH MG_ARCH_ARMGCC
+
+#define MG_ENABLE_TCPIP 1
+#define MG_ENABLE_DRIVER_W5500 1
+#define MG_ENABLE_CUSTOM_MILLIS 1
+#define MG_ENABLE_CUSTOM_RANDOM 1
+#define MG_IO_SIZE 128
+#define MG_ENABLE_LINES 1