Implement simple servo control using PWM.

stm/Makefile

@@ -62,6 +62,7 @@ SRC_STM = \
 	stm32f4xx_dma.c \
 	stm32f4xx_exti.c \
 	stm32f4xx_gpio.c \
+	stm32f4xx_tim.c \
 	stm_misc.c \
 	usb_core.c \
 	usb_dcd.c \

stm/lcd.c

@@ -88,7 +88,7 @@ int lcd_line;
 int lcd_column;
 int lcd_next_line;
 
-void lcd_init() {
+void lcd_init(void) {
     // set the outputs high
     PYB_LCD_PORT->BSRRL = PYB_LCD_CS1_PIN;
     PYB_LCD_PORT->BSRRL = PYB_LCD_RST_PIN;

stm/lcd.h

@@ -1,3 +1,3 @@
-void lcd_init();
+void lcd_init(void);
 void lcd_print_str(const char *str);
 void lcd_print_strn(const char *str, unsigned int len);

stm/led.c

@@ -9,7 +9,7 @@
 #define PYB_LED_G1_PIN (GPIO_Pin_4)
 #define PYB_LED_G2_PIN (GPIO_Pin_5)
 
-void led_init() {
+void led_init(void) {
     // set the output high (so LED is off)
     PYB_LED_R_PORT->BSRRL = PYB_LED_R1_PIN;
     PYB_LED_R_PORT->BSRRL = PYB_LED_R2_PIN;

stm/led.h

@@ -5,6 +5,6 @@ typedef enum {
     PYB_LED_G2 = 3,
 } pyb_led_t;
 
-void led_init();
+void led_init(void);
 void led_state(pyb_led_t led, int state);
 void led_toggle(pyb_led_t led);

stm/main.c

@@ -2,6 +2,7 @@
 #include <stm32f4xx.h>
 #include <stm32f4xx_rcc.h>
 #include <stm32f4xx_gpio.h>
+#include <stm32f4xx_tim.h>
 #include <stm_misc.h>
 #include "std.h"
 
@@ -32,7 +33,7 @@ void flash_error(int n) {
     led_state(PYB_LED_R2, 0);
 }
 
-static void impl02_c_version() {
+static void impl02_c_version(void) {
     int x = 0;
     while (x < 400) {
         int y = 0;
@@ -50,7 +51,7 @@ static void impl02_c_version() {
 #define PYB_USRSW_PORT (GPIOA)
 #define PYB_USRSW_PIN (GPIO_Pin_13)
 
-void sw_init() {
+void sw_init(void) {
     // make it an input with pull-up
     GPIO_InitTypeDef GPIO_InitStructure;
     GPIO_InitStructure.GPIO_Pin = PYB_USRSW_PIN;
@@ -59,7 +60,7 @@ void sw_init() {
     GPIO_Init(PYB_USRSW_PORT, &GPIO_InitStructure);
 }
 
-int sw_get() {
+int sw_get(void) {
     if (PYB_USRSW_PORT->IDR & PYB_USRSW_PIN) {
         // pulled high, so switch is not pressed
         return 0;
@@ -101,7 +102,7 @@ py_obj_t pyb_main(py_obj_t main) {
 }
 
 // sync all file systems
-py_obj_t pyb_sync() {
+py_obj_t pyb_sync(void) {
     storage_flush();
     return py_const_none;
 }
@@ -116,7 +117,7 @@ py_obj_t pyb_led(py_obj_t state) {
     return state;
 }
 
-py_obj_t pyb_sw() {
+py_obj_t pyb_sw(void) {
     if (sw_get()) {
         return py_const_true;
     } else {
@@ -131,7 +132,7 @@ void g(uint i) {
         nlr_jump((void*)(42 + i));
     }
 }
-void f() {
+void f(void) {
     nlr_buf_t nlr;
     int i;
     for (i = 0; i < 4; i++) {
@@ -149,12 +150,12 @@ void f() {
         }
     }
 }
-void nlr_test() {
+void nlr_test(void) {
     f(1);
 }
 */
 
-void fatality() {
+void fatality(void) {
     led_state(PYB_LED_R1, 1);
     led_state(PYB_LED_G1, 1);
     led_state(PYB_LED_R2, 1);
@@ -174,7 +175,7 @@ static const char fresh_boot_py[] =
 ;
 
 // get lots of info about the board
-static py_obj_t pyb_info() {
+static py_obj_t pyb_info(void) {
     // get and print clock speeds
     // SYSCLK=168MHz, HCLK=168MHz, PCLK1=42MHz, PCLK2=84MHz
     {
@@ -249,7 +250,7 @@ int readline(vstr_t *line, const char *prompt) {
     }
 }
 
-void do_repl() {
+void do_repl(void) {
     usb_vcp_send_str("Micro Python 0.5; STM32F405RG; PYBv2\r\n");
     usb_vcp_send_str("Type \"help\" for more information.\r\n");
 
@@ -352,7 +353,7 @@ bool do_file(const char *filename) {
 
 void gc_helper_get_regs_and_clean_stack(machine_uint_t *regs, machine_uint_t heap_end);
 
-void gc_collect() {
+void gc_collect(void) {
     uint32_t start = sys_tick_counter;
     gc_collect_start();
     gc_collect_root((void**)RAM_START, (((uint32_t)&_heap_start) - RAM_START) / 4);
@@ -369,12 +370,70 @@ void gc_collect() {
     printf(" 1=%lu 2=%lu m=%lu\n", info.num_1block, info.num_2block, info.max_block);
 }
 
-py_obj_t pyb_gc() {
+py_obj_t pyb_gc(void) {
     gc_collect();
     return py_const_none;
 }
 
-int main() {
+// PWM
+// TIM2 and TIM5 have CH1, CH2, CH3, CH4 on PA0-PA3 respectively
+// they are both 32-bit counters
+// 16-bit prescaler
+// TIM2_CH3 also on PB10 (used below)
+void servo_init(void) {
+    // TIM2 clock enable
+    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
+
+    // GPIOC Configuration: TIM2_CH3 (PB10)
+    GPIO_InitTypeDef GPIO_InitStructure;
+    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
+    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
+    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
+    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
+    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
+    GPIO_Init(GPIOB, &GPIO_InitStructure);
+
+    // Connect TIM2 pins to AF1
+    GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_TIM2);
+
+    // Compute the prescaler value so TIM2 runs at 100kHz
+    uint16_t PrescalerValue = (uint16_t) ((SystemCoreClock / 2) / 100000) - 1;
+
+    // Time base configuration
+    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
+    TIM_TimeBaseStructure.TIM_Period = 2000; // timer cycles at 50Hz
+    TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
+    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
+    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
+    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
+
+    // PWM1 Mode configuration: Channel1
+    TIM_OCInitTypeDef TIM_OCInitStructure;
+    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
+    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
+    TIM_OCInitStructure.TIM_Pulse = 150; // units of 10us
+    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
+    TIM_OC3Init(TIM2, &TIM_OCInitStructure);
+
+    // ?
+    TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Enable);
+
+    // ?
+    TIM_ARRPreloadConfig(TIM2, ENABLE);
+
+    // TIM2 enable counter
+    TIM_Cmd(TIM2, ENABLE);
+}
+
+py_obj_t pyb_servo_set(py_obj_t value) {
+    int v = py_get_int(value);
+    if (v < 100) { v = 100; }
+    if (v > 200) { v = 200; }
+    TIM2->CCR3 = v;
+    return py_const_none;
+}
+
+int main(void) {
     // TODO disable JTAG
 
     // set interrupt priority config to use all 4 bits for pre-empting
@@ -406,6 +465,9 @@ soft_reset:
     qstr_init();
     rt_init();
 
+    // servo
+    servo_init();
+
     // add some functions to the python namespace
     {
         py_obj_t m = py_module_new();
@@ -417,6 +479,7 @@ soft_reset:
         rt_store_attr(m, qstr_from_str_static("delay"), rt_make_function_1(pyb_delay));
         rt_store_attr(m, qstr_from_str_static("led"), rt_make_function_1(pyb_led));
         rt_store_attr(m, qstr_from_str_static("sw"), rt_make_function_0(pyb_sw));
+        rt_store_attr(m, qstr_from_str_static("servo"), rt_make_function_1(pyb_servo_set));
         rt_store_name(qstr_from_str_static("pyb"), m);
     }
 

stm/malloc0.c

@@ -49,7 +49,7 @@ void *realloc(void *ptr, size_t n) {
     return gc_realloc(ptr, n);
 }
 
-void __assert_func() {
+void __assert_func(void) {
     printf("\nASSERT FAIL!");
     for (;;) {
     }

stm/mma.c

@@ -6,7 +6,7 @@
 
 #include "mma.h"
 
-void mma_init() {
+void mma_init(void) {
     RCC->APB1ENR |= RCC_APB1ENR_I2C1EN; // enable I2C1
     //gpio_pin_init(GPIOB, 6 /* B6 is SCL */, 2 /* AF mode */, 1 /* open drain output */, 1 /* 25 MHz */, 0 /* no pull up or pull down */);
     //gpio_pin_init(GPIOB, 7 /* B7 is SDA */, 2 /* AF mode */, 1 /* open drain output */, 1 /* 25 MHz */, 0 /* no pull up or pull down */);
@@ -46,7 +46,7 @@ void mma_init() {
     // set START bit in CR1 to generate a start cond!
 }
 
-static uint32_t i2c_get_sr() {
+static uint32_t i2c_get_sr(void) {
     // must read SR1 first, then SR2, as the read can clear some flags
     uint32_t sr1 = I2C1->SR1;
     uint32_t sr2 = I2C1->SR2;
@@ -98,7 +98,7 @@ void mma_send_byte(uint8_t data) {
     }
 }
 
-uint8_t mma_read_ack() {
+uint8_t mma_read_ack(void) {
     // enable ACK of received byte
     I2C1->CR1 |= I2C_CR1_ACK;
     // wait for BUSY, MSL and RXNE (byte received)
@@ -109,7 +109,7 @@ uint8_t mma_read_ack() {
     return data;
 }
 
-uint8_t mma_read_nack() {
+uint8_t mma_read_nack(void) {
     // disable ACK of received byte (to indicate end of receiving)
     I2C1->CR1 &= (uint16_t)~((uint16_t)I2C_CR1_ACK);
     // last byte should apparently also generate a stop condition
@@ -122,7 +122,7 @@ uint8_t mma_read_nack() {
     return data;
 }
 
-void mma_stop() {
+void mma_stop(void) {
     // send stop condition
     I2C1->CR1 |= I2C_CR1_STOP;
 }

stm/mma.h

@@ -1,7 +1,7 @@
-void mma_init();
+void mma_init(void);
 void mma_restart(uint8_t addr, int write);
 void mma_start(uint8_t addr, int write);
 void mma_send_byte(uint8_t data);
-uint8_t mma_read_ack();
-uint8_t mma_read_nack();
-void mma_stop();
+uint8_t mma_read_ack(void);
+uint8_t mma_read_nack(void);
+void mma_stop(void);

stm/std.h

@@ -1,6 +1,6 @@
 typedef unsigned int size_t;
 
-void __assert_func();
+void __assert_func(void);
 
 void *malloc(size_t n);
 void free(void *ptr);

stm/storage.c

@@ -18,7 +18,7 @@ static uint32_t cache_flash_sector_start;
 static uint32_t cache_flash_sector_size;
 static bool cache_dirty;
 
-static void cache_flush() {
+static void cache_flush(void) {
     if (cache_dirty) {
         // sync the cache RAM buffer by writing it to the flash page
         flash_write(cache_flash_sector_start, (const uint32_t*)CACHE_MEM_START_ADDR, cache_flash_sector_size / 4);
@@ -45,7 +45,7 @@ static uint8_t *cache_get_addr_for_write(uint32_t flash_addr) {
     return (uint8_t*)CACHE_MEM_START_ADDR + flash_addr - flash_sector_start;
 }
 
-void storage_init() {
+void storage_init(void) {
     if (!is_initialised) {
         cache_flash_sector_id = 0;
         cache_dirty = false;
@@ -53,15 +53,15 @@ void storage_init() {
     }
 }
 
-uint32_t storage_get_block_size() {
+uint32_t storage_get_block_size(void) {
     return BLOCK_SIZE;
 }
 
-uint32_t storage_get_block_count() {
+uint32_t storage_get_block_count(void) {
     return FLASH_PART1_START_BLOCK + FLASH_PART1_NUM_BLOCKS;
 }
 
-void storage_flush() {
+void storage_flush(void) {
     cache_flush();
 }
 

stm/storage.h

@@ -1,6 +1,6 @@
-void storage_init();
-uint32_t storage_get_block_size();
-uint32_t storage_get_block_count();
-void storage_flush();
+void storage_init(void);
+uint32_t storage_get_block_size(void);
+uint32_t storage_get_block_count(void);
+void storage_flush(void);
 bool storage_read_block(uint8_t *dest, uint32_t block);
 bool storage_write_block(const uint8_t *src, uint32_t block);

stm/systick.c

@@ -4,7 +4,7 @@
 
 volatile uint32_t sys_tick_counter;
 
-void sys_tick_init() {
+void sys_tick_init(void) {
     // sys-tick interrupt called at 1ms intervals
     sys_tick_counter = 0;
     SysTick_Config(SystemCoreClock / 1000);
@@ -12,7 +12,7 @@ void sys_tick_init() {
 }
 
 // called on SysTick interrupt
-void SysTick_Handler() {
+void SysTick_Handler(void) {
     sys_tick_counter++;
 }
 

stm/systick.h

@@ -1,7 +1,7 @@
 extern volatile uint32_t sys_tick_counter;
 
-void sys_tick_init();
-void SysTick_Handler();
+void sys_tick_init(void);
+void SysTick_Handler(void);
 void sys_tick_delay_ms(uint32_t delay_ms);
 void sys_tick_wait_at_least(uint32_t stc, uint32_t delay_ms);
 bool sys_tick_has_passed(uint32_t stc, uint32_t delay_ms);

stm/usb.c

@@ -19,7 +19,7 @@ static char rx_buf[64];
 static int rx_buf_in;
 static int rx_buf_out;
 
-void usb_init() {
+void usb_init(void) {
     if (!is_enabled) {
         // only init USB once in the device's power-lifetime
         USBD_Init(&USB_OTG_dev, USB_OTG_FS_CORE_ID, &USR_desc, &USBD_PYB_cb, &USR_cb);
@@ -29,7 +29,7 @@ void usb_init() {
     is_enabled = 1;
 }
 
-bool usb_vcp_is_enabled() {
+bool usb_vcp_is_enabled(void) {
     return is_enabled;
 }
 
@@ -50,7 +50,7 @@ void usb_vcp_receive(const char *buf, uint32_t len) {
     }
 }
 
-int usb_vcp_rx_any() {
+int usb_vcp_rx_any(void) {
     if (rx_buf_in >= rx_buf_out) {
         return rx_buf_in - rx_buf_out;
     } else {
@@ -58,7 +58,7 @@ int usb_vcp_rx_any() {
     }
 }
 
-char usb_vcp_rx_get() {
+char usb_vcp_rx_get(void) {
     while (rx_buf_out == rx_buf_in) {
     }
     char c = rx_buf[rx_buf_out];

stm/usb.h

@@ -1,7 +1,7 @@
-void usb_init();
-bool usb_vcp_is_enabled();
-int usb_vcp_rx_any();
-char usb_vcp_rx_get();
+void usb_init(void);
+bool usb_vcp_is_enabled(void);
+int usb_vcp_rx_any(void);
+char usb_vcp_rx_get(void);
 void usb_vcp_send_str(const char* str);
 void usb_vcp_send_strn(const char* str, int len);
 void usb_vcp_send_strn_cooked(const char *str, int len);