From 95abd8d8d9fb9135d8d06b4db99b75d8ae6a625c Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Sun, 25 Jul 2021 10:59:43 +0200
Subject: [PATCH] protab: blink-usbboot

---
 protab/blink-usbboot/Makefile |  8 ++++++++
 protab/blink-usbboot/blink.c  | 23 +++++++++++++++++++++++
 2 files changed, 31 insertions(+)
 create mode 100644 protab/blink-usbboot/Makefile
 create mode 100644 protab/blink-usbboot/blink.c

diff --git a/protab/blink-usbboot/Makefile b/protab/blink-usbboot/Makefile
new file mode 100644
index 0000000..011261f
--- /dev/null
+++ b/protab/blink-usbboot/Makefile
@@ -0,0 +1,8 @@
+ROOT=../..
+BINARY=blink
+OBJS=blink.o
+LIB_OBJS=
+WITH_BOOT_LOADER=1
+WITH_DFU_FLASH=1
+
+include $(ROOT)/mk/bluepill.mk
diff --git a/protab/blink-usbboot/blink.c b/protab/blink-usbboot/blink.c
new file mode 100644
index 0000000..7fe240a
--- /dev/null
+++ b/protab/blink-usbboot/blink.c
@@ -0,0 +1,23 @@
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
+
+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);
+
+	for (;;) {
+		gpio_clear(GPIOC, GPIO13);
+
+		for (int i=0; i<10000000; i++)
+			asm volatile ("");
+
+		gpio_set(GPIOC, GPIO13);
+
+		for (int i=0; i<10000000; i++)
+			asm volatile ("");
+	}
+}
-- 
2.39.2