Added timer example that generates a variable frequency signal. In that particular case it is generating the SOS morse code on the eval board led.

examples/stm32/stm32-h103/Makefile

@@ -24,7 +24,7 @@ Q := @
 MAKEFLAGS += --no-print-directory
 endif
 
-all: miniblink fancyblink usart usart_irq usart_printf usart_irq_printf usb_cdcacm usb_hid button exti_both
+all: miniblink fancyblink usart usart_irq usart_printf usart_irq_printf timer usb_cdcacm usb_hid button exti_both
 
 miniblink:
 	@printf "  BUILD   examples/stm32/stm32-h103/miniblink\n"
@@ -50,6 +50,10 @@ usart_irq_printf:
 	@printf "  BUILD   examples/stm32/stm32-h103/usart_irq_printf\n"
 	$(Q)$(MAKE) -C usart_irq_printf
 
+timer:
+	@printf "  BUILD   examples/stm32/stm32-h103/timer\n"
+	$(Q)$(MAKE) -C timer
+
 spi:
 	@printf "  BUILD   examples/stm32/stm32-h103/spi\n"
 	$(Q)$(MAKE) -C spi
@@ -94,5 +98,5 @@ clean:
 	@printf "  CLEAN   examples/stm32/stm32-h103/exti_both\n"
 	$(Q)$(MAKE) -C exti_both clean
 
-.PHONY: miniblink fancyblink usart usart_irq usart_printf usart_irq_printf spi usb_cdcacm usb_hid button exti_both clean
+.PHONY: miniblink fancyblink usart usart_irq usart_printf usart_irq_printf timer spi usb_cdcacm usb_hid button exti_both clean
 

examples/stm32/stm32-h103/timer/Makefile

@@ -0,0 +1,23 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This program is free software: you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+BINARY = timer
+
+include ../../Makefile.include
+

examples/stm32/stm32-h103/timer/timer.c

@@ -0,0 +1,183 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2011 Piotr Esden-Tempski <piotr@esden.net>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/nvic.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/timer.h>
+#include <libopencm3/stm32/exti.h>
+
+u16 frequency_sequence[18] = {
+	1000,
+	500,
+	1000,
+	500,
+	1000,
+	500,
+	2000,
+	500,
+	2000,
+	500,
+	2000,
+	500,
+	1000,
+	500,
+	1000,
+	500,
+	1000,
+        5000
+};
+
+
+int frequency_sel = 0;
+
+u16 compare_time;
+u16 new_time;
+u16 frequency;
+int debug = 0;
+
+void clock_setup(void)
+{
+	rcc_clock_setup_in_hse_8mhz_out_72mhz();
+
+}
+
+void gpio_setup(void)
+{
+	/* Enable GPIOC clock. */
+	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPCEN);
+
+	/*
+	 * Set GPIO12 (PORTC) (led) to
+	 * 'output alternate function push-pull'.
+	 */
+	gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ,
+		GPIO_CNF_OUTPUT_PUSHPULL, GPIO12);
+
+	gpio_set(GPIOC, GPIO12);
+
+}
+
+void tim_setup(void)
+{
+
+	/* Enable TIM2 clock. */
+	rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_TIM2EN);
+
+
+	/* Enable TIM2 interrupt. */
+	nvic_enable_irq(NVIC_TIM2_IRQ);
+
+	/* Reset TIM2 peripheral */
+	timer_reset(TIM2);
+
+	/* Timer global mode:
+	 * - No divider
+	 * - alignment edge
+	 * - direction up
+	 */
+	timer_set_mode(TIM2, TIM_CR1_CKD_CK_INT,
+		       TIM_CR1_CMS_EDGE,
+		       TIM_CR1_DIR_UP);
+
+	/* Reset prescaler value. */
+	timer_set_prescaler(TIM2, 36000);
+
+	/* Enable preload. */
+	timer_disable_preload(TIM2);
+
+	/* Continous mode. */
+	timer_continuous_mode(TIM2);
+
+	/* Period (36kHz) */
+	timer_set_period(TIM2, 65535);
+
+	/* Disable outputs. */
+	timer_disable_oc_output(TIM2, TIM_OC1);
+	timer_disable_oc_output(TIM2, TIM_OC2);
+	timer_disable_oc_output(TIM2, TIM_OC3);
+	timer_disable_oc_output(TIM2, TIM_OC4);
+
+	/* -- OC1 configuration -- */
+
+	/* Configure global mode of line 1. */
+	timer_disable_oc_clear(TIM2, TIM_OC1);
+	timer_disable_oc_preload(TIM2, TIM_OC1);
+	timer_set_oc_slow_mode(TIM2, TIM_OC1);
+	timer_set_oc_mode(TIM2, TIM_OC1, TIM_OCM_FROZEN);
+
+	/* Set the capture compare value for OC1. */
+	timer_set_oc_value(TIM2, TIM_OC1, 1000);
+
+	/* ---- */
+	/* ARR reload enable */
+	timer_disable_preload(TIM2);
+
+	/* Counter enable */
+	timer_enable_counter(TIM2);
+
+	/* Enable commutation interrupt */
+	timer_enable_irq(TIM2, TIM_DIER_CC1IE);
+}
+
+void tim2_isr(void)
+{
+
+	if (timer_get_flag(TIM2, TIM_SR_CC1IF)) {
+
+		/* Clear compare interrupt flag. */
+		timer_clear_flag(TIM2, TIM_SR_CC1IF);
+
+		/*
+		 * Get current timer value to calculate next
+		 * compare register value
+		 */
+		compare_time = timer_get_counter(TIM2);
+
+		/*
+		 * Calculate and set the next compare value.
+		 */
+		frequency = frequency_sequence[frequency_sel++];
+		new_time = compare_time + frequency;
+
+		timer_set_oc_value(TIM2, TIM_OC1,
+				new_time);
+		if (frequency_sel == 18) {
+			frequency_sel = 0;
+		}
+
+		/* Toggle led to indicate compare event */
+		gpio_toggle(GPIOC, GPIO12);
+
+	}
+}
+
+int main(void)
+{
+
+	clock_setup();
+	gpio_setup();
+	tim_setup();
+
+	while (1) {
+		__asm("nop");
+	}
+
+	return 0;
+}

examples/stm32/stm32-h103/timer/timer.ld

@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for Olimex STM32-H103 (STM32F103RBT6, 128K flash, 20K RAM). */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 128K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32.ld
+