1 files changed, 51 insertions, 0 deletions
diff --git a/src/pwm.c b/src/pwm.c
new file mode 100644
index 0000000..787fcae
--- /dev/null
+++ b/src/pwm.c
@@ -0,0 +1,51 @@
+/*
+ * src/pwm.c
+ * (c) 2022 Jonas Gunz <himself@jonasgunz.de>
+ * License: All rights reserved.
+ */
+
+#include "pwm.h"
+
+uint8_t t0_ovf_cnt = 0;
+
+uint8_t pb0_thresh = 128;
+
+ISR(TIMER0_OVF_vect) {
+	cli();
+	/*TCNT0 = (1<<7);*/ /* Hack-increase Interrupt trigger freq */
+
+	t0_ovf_cnt ++;
+
+	if ( t0_ovf_cnt >= pb0_thresh )
+		PORTB &= ~(1<<PINB0);
+	else
+		PORTB |= (1<<PINB0);
+
+	sei();
+}
+
+ISR(TIMER2_OVF_vect) {
+	cli();
+	pb0_thresh ++;
+	sei();
+}
+
+void pwm_init() {
+	/* Pins */
+	DDRB |= (1<<PINB0);
+
+	/* Enable TIMER0 with interrupt, no prescaler */
+	TCCR0 |= (1<<CS00);
+	TIMSK |= (1<<TOIE0);
+
+	/* Enable TIMER2 with interrupt, Clk divide by 1024 */
+	/*
+	TCCR2 |= (7<<CS20);
+	TIMSK |= (1<<TOIE2);
+	*/
+}
+
+void pwm_set_pin(uint8_t _pin, uint8_t _duty) {
+	if(_pin == 0)
+		pb0_thresh = _duty;
+}