minimal: Add enough code to run minimal build on STM32F4xx hardware.
Minimal support code for a Cortex-M CPU is added, along with set-up code for an STM32F4xx MCU, including a UART for a REPL. Tested on a pyboard. Code size is 77592 bytes.
This commit is contained in:
Damien George
parent
dd0a0f79d7
commit
54729247e1
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@ -19,6 +19,8 @@ INC += -I../stmhal
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INC += -I$(BUILD)
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ifeq ($(CROSS), 1)
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DFU = ../tools/dfu.py
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PYDFU = ../tools/pydfu.py
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CFLAGS_CORTEX_M4 = -mthumb -mtune=cortex-m4 -mabi=aapcs-linux -mcpu=cortex-m4 -mfpu=fpv4-sp-d16 -mfloat-abi=hard -fsingle-precision-constant -Wdouble-promotion
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CFLAGS = $(INC) -Wall -Werror -ansi -std=gnu99 -nostdlib $(CFLAGS_CORTEX_M4) $(COPT)
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else
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@ -49,20 +51,28 @@ SRC_C = \
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lib/libc/string0.c \
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lib/mp-readline/readline.c \
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SRC_S = \
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# startup_stm32f40xx.s \
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# gchelper.s \
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OBJ = $(PY_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o) $(SRC_S:.s=.o))
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OBJ = $(PY_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
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ifeq ($(CROSS), 1)
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all: $(BUILD)/firmware.dfu
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else
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all: $(BUILD)/firmware.elf
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endif
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$(BUILD)/firmware.elf: $(OBJ)
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$(ECHO) "LINK $@"
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$(Q)$(LD) $(LDFLAGS) -o $@ $^ $(LIBS)
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$(Q)$(SIZE) $@
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$(BUILD)/firmware.dfu: $(BUILD)/firmware.elf
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$(ECHO) "Create $@"
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$(Q)$(OBJCOPY) -O binary -j .isr_vector -j .text -j .data $^ $(BUILD)/firmware.bin
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$(Q)$(PYTHON) $(DFU) -b 0x08000000:$(BUILD)/firmware.bin $@
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deploy: $(BUILD)/firmware.dfu
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$(ECHO) "Writing $< to the board"
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$(Q)$(PYTHON) $(PYDFU) -u $<
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# Run emulation build on a POSIX system with suitable terminal settings
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run:
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stty raw opost -echo
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@ -0,0 +1,35 @@
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# The minimal port
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This port is intended to be a minimal MicroPython port that actually runs.
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It can run under Linux (or similar) and on any STM32F4xx MCU (eg the pyboard).
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## Building and running Linux version
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By default the port will be built for the host machine:
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$ make
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To run a small test script do:
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$ make run
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## Building for an STM32 MCU
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The Makefile has the ability to build for a Cortex-M CPU, and by default
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includes some start-up code for an STM32F4xx MCU and also enables a UART
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for communication. To build:
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$ make CROSS=1
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If you previously built the Linux version, you will need to first run
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`make clean` to get rid of incompatible object files.
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Building will produce the build/firmware.dfu file which can be programmed
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to an MCU using:
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$ make CROSS=1 deploy
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This version of the build will work out-of-the-box on a pyboard (and
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anything similar), and will give you a MicroPython REPL on UART1 at 9600
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baud. Pin PA13 will also be driven high, and this turns on the red LED on
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the pyboard.
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159
minimal/main.c
159
minimal/main.c
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@ -94,6 +94,161 @@ void MP_WEAK __assert_func(const char *file, int line, const char *func, const c
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}
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#endif
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#if !MICROPY_MIN_USE_STDOUT
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void _start(void) {main(0, NULL);}
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#if MICROPY_MIN_USE_CORTEX_CPU
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// this is a minimal IRQ and reset framework for any Cortex-M CPU
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extern uint32_t _estack, _sidata, _sdata, _edata, _sbss, _ebss;
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void Reset_Handler(void) __attribute__((naked));
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void Reset_Handler(void) {
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// set stack pointer
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asm volatile ("ldr sp, =_estack");
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// copy .data section from flash to RAM
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for (uint32_t *src = &_sidata, *dest = &_sdata; dest < &_edata;) {
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*dest++ = *src++;
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}
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// zero out .bss section
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for (uint32_t *dest = &_sbss; dest < &_ebss;) {
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*dest++ = 0;
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}
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// jump to board initialisation
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void _start(void);
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_start();
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}
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void Default_Handler(void) {
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for (;;) {
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}
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}
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uint32_t isr_vector[] __attribute__((section(".isr_vector"))) = {
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(uint32_t)&_estack,
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(uint32_t)&Reset_Handler,
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(uint32_t)&Default_Handler, // NMI_Handler
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(uint32_t)&Default_Handler, // HardFault_Handler
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(uint32_t)&Default_Handler, // MemManage_Handler
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(uint32_t)&Default_Handler, // BusFault_Handler
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(uint32_t)&Default_Handler, // UsageFault_Handler
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0,
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0,
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0,
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0,
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(uint32_t)&Default_Handler, // SVC_Handler
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(uint32_t)&Default_Handler, // DebugMon_Handler
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0,
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(uint32_t)&Default_Handler, // PendSV_Handler
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(uint32_t)&Default_Handler, // SysTick_Handler
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};
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void _start(void) {
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// when we get here: stack is initialised, bss is clear, data is copied
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// SCB->CCR: enable 8-byte stack alignment for IRQ handlers, in accord with EABI
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*((volatile uint32_t*)0xe000ed14) |= 1 << 9;
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// initialise the cpu and peripherals
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#if MICROPY_MIN_USE_STM32_MCU
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void stm32_init(void);
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stm32_init();
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#endif
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// now that we have a basic system up and running we can call main
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main(0, NULL);
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// we must not return
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for (;;) {
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}
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}
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#endif
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#if MICROPY_MIN_USE_STM32_MCU
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// this is minimal set-up code for an STM32 MCU
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typedef struct {
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volatile uint32_t CR;
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volatile uint32_t PLLCFGR;
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volatile uint32_t CFGR;
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volatile uint32_t CIR;
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uint32_t _1[8];
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volatile uint32_t AHB1ENR;
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volatile uint32_t AHB2ENR;
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volatile uint32_t AHB3ENR;
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uint32_t _2;
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volatile uint32_t APB1ENR;
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volatile uint32_t APB2ENR;
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} periph_rcc_t;
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typedef struct {
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volatile uint32_t MODER;
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volatile uint32_t OTYPER;
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volatile uint32_t OSPEEDR;
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volatile uint32_t PUPDR;
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volatile uint32_t IDR;
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volatile uint32_t ODR;
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volatile uint16_t BSRRL;
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volatile uint16_t BSRRH;
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volatile uint32_t LCKR;
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volatile uint32_t AFR[2];
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} periph_gpio_t;
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typedef struct {
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volatile uint32_t SR;
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volatile uint32_t DR;
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volatile uint32_t BRR;
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volatile uint32_t CR1;
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} periph_uart_t;
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#define USART1 ((periph_uart_t*) 0x40011000)
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#define GPIOA ((periph_gpio_t*) 0x40020000)
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#define GPIOB ((periph_gpio_t*) 0x40020400)
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#define RCC ((periph_rcc_t*) 0x40023800)
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// simple GPIO interface
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#define GPIO_MODE_IN (0)
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#define GPIO_MODE_OUT (1)
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#define GPIO_MODE_ALT (2)
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#define GPIO_PULL_NONE (0)
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#define GPIO_PULL_UP (0)
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#define GPIO_PULL_DOWN (1)
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void gpio_init(periph_gpio_t *gpio, int pin, int mode, int pull, int alt) {
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gpio->MODER = (gpio->MODER & ~(3 << (2 * pin))) | (mode << (2 * pin));
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// OTYPER is left as default push-pull
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// OSPEEDR is left as default low speed
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gpio->PUPDR = (gpio->PUPDR & ~(3 << (2 * pin))) | (pull << (2 * pin));
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gpio->AFR[pin >> 3] = (gpio->AFR[pin >> 3] & ~(15 << (4 * (pin & 7)))) | (alt << (4 * (pin & 7)));
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}
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#define gpio_get(gpio, pin) ((gpio->IDR >> (pin)) & 1)
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#define gpio_set(gpio, pin, value) do { gpio->ODR = (gpio->ODR & ~(1 << (pin))) | (value << pin); } while (0)
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#define gpio_low(gpio, pin) do { gpio->BSRRH = (1 << (pin)); } while (0)
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#define gpio_high(gpio, pin) do { gpio->BSRRL = (1 << (pin)); } while (0)
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void stm32_init(void) {
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// basic MCU config
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RCC->CR |= (uint32_t)0x00000001; // set HSION
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RCC->CFGR = 0x00000000; // reset all
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RCC->CR &= (uint32_t)0xfef6ffff; // reset HSEON, CSSON, PLLON
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RCC->PLLCFGR = 0x24003010; // reset PLLCFGR
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RCC->CR &= (uint32_t)0xfffbffff; // reset HSEBYP
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RCC->CIR = 0x00000000; // disable IRQs
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// leave the clock as-is (internal 16MHz)
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// enable GPIO clocks
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RCC->AHB1ENR |= 0x00000003; // GPIOAEN, GPIOBEN
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// turn on an LED! (on pyboard it's the red one)
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gpio_init(GPIOA, 13, GPIO_MODE_OUT, GPIO_PULL_NONE, 0);
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gpio_high(GPIOA, 13);
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// enable UART1 at 9600 baud (TX=B6, RX=B7)
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gpio_init(GPIOB, 6, GPIO_MODE_ALT, GPIO_PULL_NONE, 7);
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gpio_init(GPIOB, 7, GPIO_MODE_ALT, GPIO_PULL_NONE, 7);
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RCC->APB2ENR |= 0x00000010; // USART1EN
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USART1->BRR = (104 << 4) | 3; // 16MHz/(16*104.1875) = 9598 baud
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USART1->CR1 = 0x0000200c; // USART enable, tx enable, rx enable
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}
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#endif
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@ -83,6 +83,11 @@ extern const struct _mp_obj_fun_builtin_t mp_builtin_open_obj;
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#define MICROPY_MIN_USE_STDOUT (1)
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#endif
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#ifdef __thumb__
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#define MICROPY_MIN_USE_CORTEX_CPU (1)
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#define MICROPY_MIN_USE_STM32_MCU (1)
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#endif
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#define MP_STATE_PORT MP_STATE_VM
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#define MICROPY_PORT_ROOT_POINTERS \
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@ -6,8 +6,6 @@
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MEMORY
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{
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FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 0x100000 /* entire flash, 1 MiB */
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FLASH_ISR (rx) : ORIGIN = 0x08000000, LENGTH = 0x004000 /* sector 0, 16 KiB */
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FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 0x080000 /* sectors 5,6,7,8, 4*128KiB = 512 KiB (could increase it more) */
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CCMRAM (xrw) : ORIGIN = 0x10000000, LENGTH = 0x010000 /* 64 KiB */
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RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 0x020000 /* 128 KiB */
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}
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@ -15,52 +13,24 @@ MEMORY
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/* top end of the stack */
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_estack = ORIGIN(RAM) + LENGTH(RAM);
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/* RAM extents for the garbage collector */
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_ram_end = ORIGIN(RAM) + LENGTH(RAM);
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_heap_end = 0x2001c000; /* tunable */
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/* define output sections */
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SECTIONS
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{
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/* The startup code goes first into FLASH */
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.isr_vector :
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{
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. = ALIGN(4);
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KEEP(*(.isr_vector)) /* Startup code */
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. = ALIGN(4);
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} >FLASH_ISR
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/* The program code and other data goes into FLASH */
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.text :
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{
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. = ALIGN(4);
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KEEP(*(.isr_vector)) /* isr vector table */
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*(.text) /* .text sections (code) */
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*(.text*) /* .text* sections (code) */
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*(.rodata) /* .rodata sections (constants, strings, etc.) */
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*(.rodata*) /* .rodata* sections (constants, strings, etc.) */
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/* *(.glue_7) */ /* glue arm to thumb code */
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/* *(.glue_7t) */ /* glue thumb to arm code */
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. = ALIGN(4);
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_etext = .; /* define a global symbol at end of code */
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_sidata = _etext; /* This is used by the startup in order to initialize the .data secion */
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} >FLASH_TEXT
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/*
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.ARM.extab :
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{
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*(.ARM.extab* .gnu.linkonce.armextab.*)
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} >FLASH
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.ARM :
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{
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__exidx_start = .;
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*(.ARM.exidx*)
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__exidx_end = .;
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} >FLASH
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*/
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/* This is the initialized data section
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The program executes knowing that the data is in the RAM
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but the loader puts the initial values in the FLASH (inidata).
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@ -69,7 +39,6 @@ SECTIONS
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{
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. = ALIGN(4);
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_sdata = .; /* create a global symbol at data start; used by startup code in order to initialise the .data section in RAM */
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_ram_start = .; /* create a global symbol at ram start for garbage collector */
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*(.data) /* .data sections */
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*(.data*) /* .data* sections */
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@ -90,28 +59,5 @@ SECTIONS
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_ebss = .; /* define a global symbol at bss end; used by startup code */
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} >RAM
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/* this is to define the start of the heap, and make sure we have a minimum size */
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.heap :
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{
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. = ALIGN(4);
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_heap_start = .; /* define a global symbol at heap start */
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} >RAM
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/* this just checks there is enough RAM for the stack */
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.stack :
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{
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. = ALIGN(4);
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} >RAM
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/* Remove information from the standard libraries */
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/*
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/DISCARD/ :
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{
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libc.a ( * )
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libm.a ( * )
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libgcc.a ( * )
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}
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*/
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.ARM.attributes 0 : { *(.ARM.attributes) }
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}
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@ -5,12 +5,25 @@
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* Core UART functions to implement for a port
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*/
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#if MICROPY_MIN_USE_STM32_MCU
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typedef struct {
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volatile uint32_t SR;
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volatile uint32_t DR;
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} periph_uart_t;
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#define USART1 ((periph_uart_t*)0x40011000)
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#endif
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// Receive single character
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int mp_hal_stdin_rx_chr(void) {
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unsigned char c = 0;
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#if MICROPY_MIN_USE_STDOUT
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int r = read(0, &c, 1);
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(void)r;
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#elif MICROPY_MIN_USE_STM32_MCU
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// wait for RXNE
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while ((USART1->SR & (1 << 5)) == 0) {
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}
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c = USART1->DR;
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#endif
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return c;
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}
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@ -20,5 +33,12 @@ void mp_hal_stdout_tx_strn(const char *str, mp_uint_t len) {
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#if MICROPY_MIN_USE_STDOUT
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int r = write(1, str, len);
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(void)r;
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#elif MICROPY_MIN_USE_STM32_MCU
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while (len--) {
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// wait for TXE
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while ((USART1->SR & (1 << 7)) == 0) {
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}
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USART1->DR = *str++;
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}
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#endif
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}
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