From da2464a8d3a6c88593601abcf49d9b6c740126fe Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Tue, 30 Jul 2019 22:34:19 +0200
Subject: [PATCH] Protab: Blink with systick

---
 protab/blink2/Makefile |  6 ++++++
 protab/blink2/blink.c  | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)
 create mode 100644 protab/blink2/Makefile
 create mode 100644 protab/blink2/blink.c

diff --git a/protab/blink2/Makefile b/protab/blink2/Makefile
new file mode 100644
index 0000000..17a67e8
--- /dev/null
+++ b/protab/blink2/Makefile
@@ -0,0 +1,6 @@
+ROOT=../..
+BINARY=blink
+OBJS=blink.o
+LIB_OBJS=
+
+include $(ROOT)/mk/bluepill.mk
diff --git a/protab/blink2/blink.c b/protab/blink2/blink.c
new file mode 100644
index 0000000..605e113
--- /dev/null
+++ b/protab/blink2/blink.c
@@ -0,0 +1,33 @@
+#include <libopencm3/cm3/systick.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
+
+static void delay_ms(unsigned int ms)
+{
+	systick_clear();
+	for (unsigned int i=0; i<ms; i++)
+		while (!systick_get_countflag())
+			;
+}
+
+int main(void)
+{
+	rcc_clock_setup_in_hse_8mhz_out_72mhz();
+	rcc_periph_clock_enable(RCC_GPIOC);
+
+	// PC13 = BluePill LED
+	gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
+
+	systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
+	systick_set_reload(71999);
+	systick_counter_enable();
+
+	for (;;) {
+		gpio_clear(GPIOC, GPIO13);
+		delay_ms(100);
+		gpio_set(GPIOC, GPIO13);
+		delay_ms(500);
+	}
+
+	return 0;
+}
-- 
2.39.2