cleanup, added timebase code (scheduled tasks, ms delay, time base)

Makefile

@@ -10,15 +10,16 @@ LDSCRIPT    = stm32l100rc.ld
 # Main file
 BINARY      = main
 
-INCL_DIRS   = . lib source
-SRC_DIR     = source
+INCL_DIRS   = . lib utils
 
 STARTUP_SCRIPT = startup_stm32l100xc.s
 
-OBJS += $(BINARY).o $(STARTUP_SCRIPT:.s=.o)
-OBJS += lib/gpio.o
-OBJS += lib/systick.o
-OBJS += lib/usart.o
+OBJS += $(BINARY).o
+OBJS += $(STARTUP_SCRIPT:.s=.o)
+OBJS += utils/gpio.o
+OBJS += utils/usart.o
+OBJS += utils/timebase.o
+OBJS += init.o
 
 ################################################################
 

init.c

@@ -0,0 +1,59 @@
+#include "init.h"
+
+#include "utils/gpio.h"
+#include "utils/usart.h"
+
+
+void init_gpios(void)
+{
+	gpio_enable(GPIOA);
+	gpio_enable(GPIOB);
+	gpio_enable(GPIOC);
+
+	gpio_set_mode(GPIOC, BIT8 | BIT9 | BIT7, MODER_OUTPUT);
+}
+
+
+
+void init_clock(void)
+{
+	// Flash timing - 64-bit access, pre-fetch, latency = 1
+	FLASH_ACR |= FLASH_ACR_ACC64; // Cannot write both at once
+	FLASH_ACR |= FLASH_ACR_PRFTEN | FLASH_ACR_LATENCY;
+
+	// Power on HSI (runs from MSI on start)
+	RCC_CR |= RCC_CR_HSION;
+
+	// Wait for HSIRDY
+	while (!(RCC_CR & RCC_CR_HSIRDY));
+
+	// Select HSI as the core clock source
+	RCC_CFGR &= ~RCC_CFGR_SW;
+	RCC_CFGR |= RCC_CFGR_SW_HSI;
+}
+
+
+
+void init_usart(void)
+{
+	gpio_set_af(GPIOC, BIT10 | BIT11, AF7);
+
+	// USART at C10 (tx), C11 (rx)
+	RCC_APB1ENR |= RCC_APB1ENR_USART3EN;
+
+	// RATE 9600Bd 104.1875 (see datasheet for reference)
+	//USART3_BRR = 0x00683; // 9600 @ 16MHz
+	USART3_BRR = 0x0008A; // 115200 @ 16MHz
+
+	// USART enable
+	USART3_CR1 = USART_CR1_UE | USART_CR1_RE | USART_CR1_TE;
+}
+
+
+
+void init_systick(void)
+{
+	SysTick_CSR = (SysTick_CSR & ~SysTick_CSR_CLKSOURCE) | SysTick_CSR_CLKSOURCE_CORE;
+	SysTick_RELOAD = 16000; // 1ms interrupt @ 16MHz core clock
+	SysTick_CSR |= SysTick_CSR_TICKINT | SysTick_CSR_ENABLE;
+}

init.h

@@ -0,0 +1,7 @@
+#pragma once
+#include <common.h>
+
+void init_clock(void);
+void init_gpios(void);
+void init_usart(void);
+void init_systick(void);

lib/defs_gpio.h

@@ -6,6 +6,32 @@
 // DATE   : 10/2015
 // DESCR  : Control registers and bit masks for GPIO
 
+enum GPIO_MODE {
+	MODER_INPUT = 0,
+	MODER_OUTPUT = 1,
+	MODER_AF = 2,
+	MODER_ANALOG = 3,
+};
+
+enum GPIO_AF {
+	AF0 = 0,
+	AF1 = 1,
+	AF2 = 2,
+	AF3 = 3,
+	AF4 = 4,
+	AF5 = 5,
+	AF6 = 6,
+	AF7 = 7,
+	AF8 = 8,
+	AF9 = 9,
+	AF10 = 10,
+	AF11 = 11,
+	AF12 = 12,
+	AF13 = 13,
+	AF14 = 14,
+	AF15 = 15,
+};
+
 
 // offsets
 #define GPIO_MODER_offs    0x00  // GPIO pin mode register,

lib/systick.c

@@ -1,20 +0,0 @@
-#include "systick.h"
-
-void systick_setup(uint32_t prescaller)
-{
-	SysTick_CSR = (SysTick_CSR & ~SysTick_CSR_CLKSOURCE) | SysTick_CSR_CLKSOURCE_CORE;
-	SysTick_RELOAD = prescaller;
-	SysTick_CSR |= SysTick_CSR_TICKINT | SysTick_CSR_ENABLE;
-}
-
-
-void systick_enable(void)
-{
-	SysTick_CSR |= SysTick_CSR_ENABLE;
-}
-
-
-void systick_disable(void)
-{
-	SysTick_CSR &= ~SysTick_CSR_ENABLE;
-}

lib/systick.h

@@ -1,20 +0,0 @@
-#pragma once
-#include "common.h"
-
-// don't forget to implement the handler:
-// void SysTick_Handler(void)
-
-
-/**
- * Set up and start systick
- * @param prescaller divider (eg. for 1ms @ 16MHz: 16000)
- */
-void systick_setup(uint32_t prescaller);
-
-
-/** Enable (start) systick */
-void systick_enable(void);
-
-
-/** Disable (stop) systick */
-void systick_disable(void);

main.c

@@ -1,92 +1,33 @@
 #include <common.h>
-#include <gpio.h>
-#include <systick.h>
-#include <usart.h>
 
+#include "utils/usart.h"
+#include "utils/timebase.h"
 
-static void init_gpios(void)
-{
-	gpio_enable(GPIOA);
-	gpio_enable(GPIOB);
-	gpio_enable(GPIOC);
+#include "init.h"
 
-	gpio_set_mode(GPIOC, BIT8 | BIT9 | BIT7, MODER_OUTPUT);
 
-	gpio_set_mode(GPIOA, BIT8, MODER_OUTPUT);
+void blink(void) {
+	GPIOC_ODR ^= BIT9;
 }
 
 
-static void init_clock(void)
-{
-	// Flash timing - 64-bit access, pre-fetch, latency = 1
-	FLASH_ACR |= FLASH_ACR_ACC64; // Cannot write both at once
-	FLASH_ACR |= FLASH_ACR_PRFTEN | FLASH_ACR_LATENCY;
-
-	// Power on HSI (runs from MSI on start)
-	RCC_CR |= RCC_CR_HSION;
-
-	// Wait for HSIRDY
-	while (!(RCC_CR & RCC_CR_HSIRDY));
-
-	// Select HSI as the core clock source
-	RCC_CFGR &= ~RCC_CFGR_SW;
-	RCC_CFGR |= RCC_CFGR_SW_HSI;
-}
-
-
-static void init_usart(void)
-{
-	gpio_set_af(GPIOC, BIT10 | BIT11, AF7);
-
-	// USART at C11, C12
-	RCC_APB1ENR |= RCC_APB1ENR_USART3EN;
-
-	// RATE 9600Bd 104.1875 (see datasheet for reference)8.6875
-	//USART3_BRR = 0x00683; // 9600
-	USART3_BRR = 0x0008A; // 115200
-
-	// USART enable
-	USART3_CR1 = USART_CR1_UE | USART_CR1_RE | USART_CR1_TE;
-}
-
 
 /** Called before main() */
 void SystemInit(void)
 {
 	init_clock();
-	systick_setup(16000);
+	init_systick();
 	init_gpios();
 	init_usart();
-}
-
-
 
-static uint32_t time = 0;
-
-/** IRQ */
-void SysTick_Handler(void)
-{
-	time++;
-	if (time == 500) {
-		time = 0;
-		GPIOC_ODR ^= BIT9;
-	}
-}
-
-
-
-void delay(void)
-{
-	for (int i = 0; i < 800000; i++) {
-		__asm__("nop");
-	}
+	schedule_timed_task(blink, 500);
 }
 
 
 int main(void)
 {
 	while (1) {
-		delay();
+		delay_ms(1000);
 		GPIOC_ODR ^= BIT8;
 
 		usart_tx_string(USART3, "HELLO\r\n");

proj.pro

@@ -19,8 +19,14 @@ DISTFILES += \
 SOURCES += \
     main.c \
     lib/gpio.c \
-    lib/systick.c \
-    lib/usart.c
+    lib/usart.c \
+    init.c \
+    timebase.c \
+    gpio.c \
+    usart.c \
+    utils/gpio.c \
+    utils/timebase.c \
+    utils/usart.c
 
 HEADERS += \
     lib/common.h \
@@ -28,9 +34,14 @@ HEADERS += \
     lib/defs_flash.h \
     lib/defs_gpio.h \
     lib/defs_rcc.h \
-    lib/gpio.h \
     lib/defs_systick.h \
-    lib/systick.h \
     lib/defs_usart.h \
-    lib/usart.h
+    lib/usart.h \
+    init.h \
+    timebase.h \
+    gpio.h \
+    usart.h \
+    utils/gpio.h \
+    utils/timebase.h \
+    utils/usart.h
 

utils/gpio.c

@@ -41,17 +41,13 @@ void gpio_disable(uint32_t gpio)
 void gpio_set_af(uint32_t gpio, uint32_t pins, enum GPIO_AF af)
 {
 	gpio_enable(gpio);
+	gpio_set_mode(gpio, pins, MODER_AF);
 
-	io32_t moder = P_REG(gpio, GPIO_MODER_offs);
 	io32_t afrl = P_REG(gpio, GPIO_AFRL_offs);
 	io32_t afrh = P_REG(gpio, GPIO_AFRH_offs);
 
 	BitFieldLoop(i, m, 16) {
 		if (pins & m) {
-			// set pin mode to AF
-			*moder &= ~(0b11 << i * 2);
-			*moder |= MODER_AF << i * 2;
-
 			if (i < 8) {
 				*afrl &= ~(0xF << i * 4);
 				*afrl |= af << i * 4;

utils/gpio.h

@@ -2,33 +2,6 @@
 
 #include "common.h"
 
-enum GPIO_MODE {
-	MODER_INPUT = 0,
-	MODER_OUTPUT = 1,
-	MODER_AF = 2,
-	MODER_ANALOG = 3,
-};
-
-enum GPIO_AF {
-	AF0 = 0,
-	AF1 = 1,
-	AF2 = 2,
-	AF3 = 3,
-	AF4 = 4,
-	AF5 = 5,
-	AF6 = 6,
-	AF7 = 7,
-	AF8 = 8,
-	AF9 = 9,
-	AF10 = 10,
-	AF11 = 11,
-	AF12 = 12,
-	AF13 = 13,
-	AF14 = 14,
-	AF15 = 15,
-};
-
-
 /**
  * Enable GPIO in RCC
  * @param gpio GPIO base

utils/timebase.c

@@ -0,0 +1,68 @@
+#include "timebase.h"
+
+volatile uint32_t TIME_MS;
+
+#define TASK_COUNT 10
+
+// --- time scheduler system ---
+typedef struct {
+	/** User callback */
+	void (*callback) (void);
+	/** Callback interval */
+	uint32_t interval_ms;
+	/** Counter, when reaches interval_ms, is cleared and callback is called. */
+	uint32_t countup;
+} timebase_cb_t;
+
+static uint8_t scheduled_task_n = 0;
+static timebase_cb_t scheduled_tasks[TASK_COUNT];
+
+
+bool schedule_timed_task(void (*callback) (void), uint32_t interval_ms)
+{
+	if (scheduled_task_n >= TASK_COUNT) return false;
+
+	// add the task
+	timebase_cb_t *task = &scheduled_tasks[scheduled_task_n++];
+	task->callback = callback;
+	task->countup = 0;
+	task->interval_ms = interval_ms;
+
+	return true;
+}
+
+
+/** IRQ */
+void SysTick_Handler(void)
+{
+	TIME_MS++;
+
+	// run scheduled tasks
+	for (int i = 0; i < scheduled_task_n; i++) {
+		timebase_cb_t *task = &scheduled_tasks[i];
+		if (task->countup++ >= task->interval_ms) {
+			task->callback();
+			task->countup = 0;
+		}
+	}
+}
+
+
+void delay_ms(uint32_t ms)
+{
+	uint32_t last_ms = TIME_MS;
+
+	while (ms-- != 0) {
+		while (TIME_MS == last_ms);
+		last_ms = TIME_MS;
+	}
+}
+
+
+
+void delay_s(uint32_t s)
+{
+	while (s-- != 0) {
+		delay_ms(1000);
+	}
+}

utils/timebase.h

@@ -0,0 +1,10 @@
+#pragma once
+#include <common.h>
+
+extern volatile uint32_t TIME_MS;
+
+void delay_ms(uint32_t ms);
+void delay_s(uint32_t s);
+
+/** Schedule a timed task (like a cron job) */
+bool schedule_timed_task(void (*callback) (void), uint32_t interval_ms);

utils/usart.c

@@ -73,8 +73,9 @@ void usart_tx_char(uint32_t usart, uint8_t c)
 	*DR = c;
 }
 
+
 /** Transmit a string until \0 */
-void usart_tx_string(uint32_t usart, char *string)
+void usart_tx_string(uint32_t usart, const char *string)
 {
 	char c;
 	while ((c = *string++) != 0) {

utils/usart.h

@@ -28,4 +28,4 @@ bool usart_tx_ready(uint32_t usart);
 void usart_tx_char(uint32_t usart, uint8_t c);
 
 /** Transmit a string until \0 */
-void usart_tx_string(uint32_t usart, char *string);
+void usart_tx_string(uint32_t usart, const char *string);