Merge pull request #77 from b3nn0/pi4-pwm-freq

Fixed PI4 PWM frequency setting due to wrong oscillator frequency
stianeikeland · Sep 20, 2021 · 2ab4c04 · 2ab4c04
2 parents 8a909a0 + 43c0fe3
commit 2ab4c04
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/rpio.go b/rpio.go
@@ -546,7 +546,10 @@ func PullMode(pin Pin, pull Pull) {
 //   pwm_clk: pins 12, 13, 18, 19, 40, 41, 45
 func SetFreq(pin Pin, freq int) {
 	// TODO: would be nice to choose best clock source depending on target frequency, oscilator is used for now
-	const sourceFreq = 19200000 // oscilator frequency
+	sourceFreq := 19200000 // oscilator frequency
+	if isBCM2711() {
+		sourceFreq = 52000000
+	}
 	const divMask = 4095        // divi and divf have 12 bits each
 
 	divi := uint32(sourceFreq / freq)