Add license header and minor improvements

1 files changed, 23 insertions, 2 deletions

diff --git a/firmware/main.c b/firmware/main.c
index 8e39278..264d3f5 100644
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -1,6 +1,27 @@
 // vim: shiftwidth=4 tabstop=4 noexpandtab
 
 
+/*
+  ledcontrol firmware
+  Copyright (C) 2021  xengineering
+
+  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 <https://www.gnu.org/licenses/>.
+
+  Contact: me@xengineering.eu
+*/
+
+
 #include <libopencm3/stm32/rcc.h>
 #include <libopencm3/stm32/gpio.h>
 #include <libopencm3/stm32/timer.h>
@@ -15,11 +36,10 @@ static void timer_init(void);
 void tim2_isr(void);
 
 
-void main(void)
+int main(void)
 {
 	clock_init();
 	gpio_init();
-	gpio_clear(GPIOC, GPIO13);  // set onboard LED on
 	nvic_init();
 	timer_init();
 
@@ -56,6 +76,7 @@ static void gpio_init(void)
 		GPIO_CNF_OUTPUT_PUSHPULL,
 		GPIO13
 	);
+	gpio_clear(GPIOC, GPIO13);  // set initial value to 'on'
 	
 	// setup PB0 (connected to TIM3_CH3) for PWM
 	gpio_set_mode(