diff --git a/src/machine/machine.go b/src/machine/machine.go
index d40c39f0..aa1a2f6b 100644
--- a/src/machine/machine.go
+++ b/src/machine/machine.go
@@ -10,6 +10,11 @@ var (
 	ErrNoPinChangeChannel = errors.New("machine: no channel available for pin interrupt")
 )
 
+// PinMode sets the direction and pull mode of the pin. For example, PinOutput
+// sets the pin as an output and PinInputPullup sets the pin as an input with a
+// pull-up.
+type PinMode uint8
+
 type PinConfig struct {
 	Mode PinMode
 }
diff --git a/src/machine/machine_atsamd21.go b/src/machine/machine_atsamd21.go
index aca801c5..4bacd2aa 100644
--- a/src/machine/machine_atsamd21.go
+++ b/src/machine/machine_atsamd21.go
@@ -16,8 +16,6 @@ import (
 	"unsafe"
 )
 
-type PinMode uint8
-
 const (
 	PinAnalog    PinMode = 1
 	PinSERCOM    PinMode = 2
diff --git a/src/machine/machine_atsamd51.go b/src/machine/machine_atsamd51.go
index 0ce476cc..f8b0a865 100644
--- a/src/machine/machine_atsamd51.go
+++ b/src/machine/machine_atsamd51.go
@@ -20,8 +20,6 @@ func CPUFrequency() uint32 {
 	return 120000000
 }
 
-type PinMode uint8
-
 const (
 	PinAnalog        PinMode = 1
 	PinSERCOM        PinMode = 2
diff --git a/src/machine/machine_avr.go b/src/machine/machine_avr.go
index 5cf70cca..14ba5020 100644
--- a/src/machine/machine_avr.go
+++ b/src/machine/machine_avr.go
@@ -8,8 +8,6 @@ import (
 	"unsafe"
 )
 
-type PinMode uint8
-
 const (
 	PinInput PinMode = iota
 	PinInputPullup
diff --git a/src/machine/machine_esp32.go b/src/machine/machine_esp32.go
index 1526fc16..fd4fa062 100644
--- a/src/machine/machine_esp32.go
+++ b/src/machine/machine_esp32.go
@@ -21,8 +21,6 @@ var (
 	ErrInvalidSPIBus = errors.New("machine: invalid SPI bus")
 )
 
-type PinMode uint8
-
 const (
 	PinOutput PinMode = iota
 	PinInput
diff --git a/src/machine/machine_esp8266.go b/src/machine/machine_esp8266.go
index 5570e7e0..19c5dd0a 100644
--- a/src/machine/machine_esp8266.go
+++ b/src/machine/machine_esp8266.go
@@ -11,8 +11,6 @@ func CPUFrequency() uint32 {
 	return 80000000 // 80MHz
 }
 
-type PinMode uint8
-
 const (
 	PinOutput PinMode = iota
 	PinInput
diff --git a/src/machine/machine_fe310.go b/src/machine/machine_fe310.go
index ae618e58..3af8acc4 100644
--- a/src/machine/machine_fe310.go
+++ b/src/machine/machine_fe310.go
@@ -12,8 +12,6 @@ func CPUFrequency() uint32 {
 	return 16000000
 }
 
-type PinMode uint8
-
 const (
 	PinInput PinMode = iota
 	PinOutput
diff --git a/src/machine/machine_gameboyadvance.go b/src/machine/machine_gameboyadvance.go
index d592a1eb..100c2bce 100644
--- a/src/machine/machine_gameboyadvance.go
+++ b/src/machine/machine_gameboyadvance.go
@@ -30,8 +30,6 @@ const (
 // Make it easier to directly write to I/O RAM.
 var ioram = (*[0x400]volatile.Register8)(unsafe.Pointer(uintptr(0x04000000)))
 
-type PinMode uint8
-
 // Set has not been implemented.
 func (p Pin) Set(value bool) {
 	// do nothing
diff --git a/src/machine/machine_generic.go b/src/machine/machine_generic.go
index d482e0e3..16948a49 100644
--- a/src/machine/machine_generic.go
+++ b/src/machine/machine_generic.go
@@ -10,8 +10,6 @@ var (
 	UART0 = UART{0}
 )
 
-type PinMode uint8
-
 const (
 	PinInput PinMode = iota
 	PinOutput
diff --git a/src/machine/machine_k210.go b/src/machine/machine_k210.go
index 3baef329..f009e152 100644
--- a/src/machine/machine_k210.go
+++ b/src/machine/machine_k210.go
@@ -14,7 +14,6 @@ func CPUFrequency() uint32 {
 	return 390000000
 }
 
-type PinMode uint8
 type fpioaPullMode uint8
 type PinChange uint8
 
diff --git a/src/machine/machine_mimxrt1062.go b/src/machine/machine_mimxrt1062.go
index 42586c42..38cb71f7 100644
--- a/src/machine/machine_mimxrt1062.go
+++ b/src/machine/machine_mimxrt1062.go
@@ -15,8 +15,6 @@ func CPUFrequency() uint32 {
 	return 600000000
 }
 
-type PinMode uint8
-
 const (
 	// GPIO
 	PinInput PinMode = iota
diff --git a/src/machine/machine_nrf.go b/src/machine/machine_nrf.go
index e8488c79..c49096e8 100644
--- a/src/machine/machine_nrf.go
+++ b/src/machine/machine_nrf.go
@@ -13,8 +13,6 @@ var (
 	ErrTxInvalidSliceSize = errors.New("SPI write and read slices must be same size")
 )
 
-type PinMode uint8
-
 const (
 	PinInput         PinMode = (nrf.GPIO_PIN_CNF_DIR_Input << nrf.GPIO_PIN_CNF_DIR_Pos) | (nrf.GPIO_PIN_CNF_INPUT_Connect << nrf.GPIO_PIN_CNF_INPUT_Pos)
 	PinInputPullup   PinMode = PinInput | (nrf.GPIO_PIN_CNF_PULL_Pullup << nrf.GPIO_PIN_CNF_PULL_Pos)
diff --git a/src/machine/machine_nxpmk66f18.go b/src/machine/machine_nxpmk66f18.go
index 63f7b58e..35e48e5c 100644
--- a/src/machine/machine_nxpmk66f18.go
+++ b/src/machine/machine_nxpmk66f18.go
@@ -37,8 +37,6 @@ import (
 	"unsafe"
 )
 
-type PinMode uint8
-
 const (
 	PinInput PinMode = iota
 	PinInputPullUp
diff --git a/src/machine/machine_stm32.go b/src/machine/machine_stm32.go
index 8ef5fed7..363036ca 100644
--- a/src/machine/machine_stm32.go
+++ b/src/machine/machine_stm32.go
@@ -17,8 +17,6 @@ const (
 	portJ
 )
 
-type PinMode uint8
-
 // Peripheral operations sequence:
 //  1. Enable the clock to the alternate function.
 //  2. Enable clock to corresponding GPIO