diff --git a/src/examples/pwm/arduino-uno-q.go b/src/examples/pwm/arduino-uno-q.go
new file mode 100644
index 000000000..e0c2c53a5
--- /dev/null
+++ b/src/examples/pwm/arduino-uno-q.go
@@ -0,0 +1,11 @@
+//go:build arduino_uno_q
+
+package main
+
+import "machine"
+
+var (
+	pwm  = &machine.TIM3
+	pinA = machine.D3 // PB0 = TIM3_CH3
+	pinB = machine.D6 // PB1 = TIM3_CH4
+)
diff --git a/src/machine/board_arduino_uno_q.go b/src/machine/board_arduino_uno_q.go
index 9e8996d9f..9c2296bc8 100644
--- a/src/machine/board_arduino_uno_q.go
+++ b/src/machine/board_arduino_uno_q.go
@@ -27,24 +27,24 @@ const (
 	ADC4 = A4
 	ADC5 = A5
 
-	D0  = PB7
-	D1  = PB6
-	D2  = PB3
-	D3  = PB0
+	D0  = PB7 // USART1 RX, PWM TIM4_CH2
+	D1  = PB6 // USART1 TX, PWM TIM4_CH1
+	D2  = PB3 // PWM TIM2_CH2
+	D3  = PB0 // PWM TIM3_CH3
 	D4  = PA12
-	D5  = PA11
-	D6  = PB1
+	D5  = PA11 // PWM TIM1_CH4
+	D6  = PB1  // PWM TIM3_CH4
 	D7  = PB2
-	D8  = PB4
-	D9  = PB8
-	D10 = PB9
-	D11 = PB15
-	D12 = PB14
+	D8  = PB4  // PWM TIM3_CH1
+	D9  = PB8  // PWM TIM4_CH3 / TIM16_CH1
+	D10 = PB9  // PWM TIM4_CH4 / TIM17_CH1
+	D11 = PB15 // PWM TIM15_CH2
+	D12 = PB14 // PWM TIM15_CH1
 	D13 = PB13
 	D18 = PC1
 	D19 = PC0
-	D20 = PB10
-	D21 = PB11
+	D20 = PB10 // I2C2 SCL, PWM TIM2_CH3
+	D21 = PB11 // I2C2 SDA, PWM TIM2_CH4
 )
 
 const (