diff --git a/ports/stm32f4/common-hal/digitalio/DigitalInOut.c b/ports/stm32f4/common-hal/digitalio/DigitalInOut.c
index e19988a7f7..6f2a0976e3 100644
--- a/ports/stm32f4/common-hal/digitalio/DigitalInOut.c
+++ b/ports/stm32f4/common-hal/digitalio/DigitalInOut.c
@@ -33,7 +33,7 @@
 
 void common_hal_digitalio_digitalinout_never_reset(
         digitalio_digitalinout_obj_t *self) {
-    never_reset_pin_number(self->pin->number);
+    never_reset_pin_number(self->pin->port, self->pin->number);
 }
 
 digitalinout_result_t common_hal_digitalio_digitalinout_construct(
@@ -43,7 +43,7 @@ digitalinout_result_t common_hal_digitalio_digitalinout_construct(
     self->pin = pin;
 
     GPIO_InitTypeDef GPIO_InitStruct = {0};
-    GPIO_InitStruct.Pin = (pin_mask(self->pin->number));
+    GPIO_InitStruct.Pin = 1<<self->pin->number;
     GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
     GPIO_InitStruct.Pull = GPIO_NOPULL;
     GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
@@ -61,7 +61,7 @@ void common_hal_digitalio_digitalinout_deinit(digitalio_digitalinout_obj_t *self
         return;
     }
 
-    reset_pin_number(self->pin->number);
+    reset_pin_number(self->pin->port, self->pin->number);
     self->pin = mp_const_none;
 }
 
@@ -69,7 +69,7 @@ void common_hal_digitalio_digitalinout_switch_to_input(
         digitalio_digitalinout_obj_t *self, digitalio_pull_t pull) {
 
     GPIO_InitTypeDef GPIO_InitStruct = {0};
-    GPIO_InitStruct.Pin = pin_mask(self->pin->number);
+    GPIO_InitStruct.Pin = 1<<self->pin->number;
     GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
     GPIO_InitStruct.Pull = GPIO_NOPULL;
     GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
@@ -89,27 +89,27 @@ void common_hal_digitalio_digitalinout_switch_to_output(
 digitalio_direction_t common_hal_digitalio_digitalinout_get_direction(
         digitalio_digitalinout_obj_t *self) {
 
-    return (LL_GPIO_GetPinMode(pin_port(self->pin->number), pin_mask(self->pin->number)) 
+    return (LL_GPIO_GetPinMode(pin_port(self->pin->number), 1<<self->pin->number) 
         == LL_GPIO_MODE_INPUT) ? DIRECTION_INPUT : DIRECTION_OUTPUT;
 }
 
 void common_hal_digitalio_digitalinout_set_value(
         digitalio_digitalinout_obj_t *self, bool value) {
-    HAL_GPIO_WritePin(pin_port(self->pin->number), pin_mask(self->pin->number), value);
+    HAL_GPIO_WritePin(pin_port(self->pin->number), 1<<self->pin->number, value);
 }
 
 bool common_hal_digitalio_digitalinout_get_value(
         digitalio_digitalinout_obj_t *self) {
-    return (LL_GPIO_GetPinMode(pin_port(self->pin->number), pin_mask(self->pin->number)) == LL_GPIO_MODE_INPUT)
-        ? HAL_GPIO_ReadPin(pin_port(self->pin->number), pin_mask(self->pin->number))
-        : LL_GPIO_IsOutputPinSet(pin_port(self->pin->number), pin_mask(self->pin->number));
+    return (LL_GPIO_GetPinMode(pin_port(self->pin->number), 1<<self->pin->number) == LL_GPIO_MODE_INPUT)
+        ? HAL_GPIO_ReadPin(pin_port(self->pin->number), 1<<self->pin->number)
+        : LL_GPIO_IsOutputPinSet(pin_port(self->pin->number), 1<<self->pin->number);
 }
 
 void common_hal_digitalio_digitalinout_set_drive_mode(
         digitalio_digitalinout_obj_t *self,
         digitalio_drive_mode_t drive_mode) {
     GPIO_InitTypeDef GPIO_InitStruct = {0};
-    GPIO_InitStruct.Pin = pin_mask(self->pin->number);
+    GPIO_InitStruct.Pin = 1<<self->pin->number;
     GPIO_InitStruct.Mode = (drive_mode == DRIVE_MODE_OPEN_DRAIN ? 
         GPIO_MODE_OUTPUT_OD : GPIO_MODE_OUTPUT_PP);
     GPIO_InitStruct.Pull = GPIO_NOPULL;
@@ -120,7 +120,7 @@ void common_hal_digitalio_digitalinout_set_drive_mode(
 digitalio_drive_mode_t common_hal_digitalio_digitalinout_get_drive_mode(
         digitalio_digitalinout_obj_t *self) {
 
-    return LL_GPIO_GetPinOutputType(pin_port(self->pin->number), pin_mask(self->pin->number)) 
+    return LL_GPIO_GetPinOutputType(pin_port(self->pin->number), 1<<self->pin->number) 
         == LL_GPIO_OUTPUT_OPENDRAIN ? DRIVE_MODE_OPEN_DRAIN : DRIVE_MODE_PUSH_PULL;
 }
 
@@ -129,13 +129,13 @@ void common_hal_digitalio_digitalinout_set_pull(
 
     switch (pull) {
         case PULL_UP:
-            LL_GPIO_SetPinPull(pin_port(self->pin->number), pin_mask(self->pin->number),LL_GPIO_PULL_UP);
+            LL_GPIO_SetPinPull(pin_port(self->pin->number), 1<<self->pin->number,LL_GPIO_PULL_UP);
             break;
         case PULL_DOWN:
-            LL_GPIO_SetPinPull(pin_port(self->pin->number), pin_mask(self->pin->number),LL_GPIO_PULL_DOWN);
+            LL_GPIO_SetPinPull(pin_port(self->pin->number), 1<<self->pin->number,LL_GPIO_PULL_DOWN);
             break;
         case PULL_NONE:
-            LL_GPIO_SetPinPull(pin_port(self->pin->number), pin_mask(self->pin->number),LL_GPIO_PULL_NO);
+            LL_GPIO_SetPinPull(pin_port(self->pin->number), 1<<self->pin->number,LL_GPIO_PULL_NO);
             break;
         default:
             break;
@@ -146,7 +146,7 @@ digitalio_pull_t common_hal_digitalio_digitalinout_get_pull(
         digitalio_digitalinout_obj_t *self) {
     
 
-    switch (LL_GPIO_GetPinPull(pin_port(self->pin->number), pin_mask(self->pin->number))) {
+    switch (LL_GPIO_GetPinPull(pin_port(self->pin->number), 1<<self->pin->number)) {
         case LL_GPIO_PULL_UP:
             return PULL_UP;
         case LL_GPIO_PULL_DOWN:
diff --git a/ports/stm32f4/common-hal/microcontroller/Pin.c b/ports/stm32f4/common-hal/microcontroller/Pin.c
index 2e0da9ccbe..3a2dd01c58 100644
--- a/ports/stm32f4/common-hal/microcontroller/Pin.c
+++ b/ports/stm32f4/common-hal/microcontroller/Pin.c
@@ -53,40 +53,40 @@ void reset_all_pins(void) {
 }
 
 // Mark pin as free and return it to a quiescent state.
-void reset_pin_number(uint8_t pin) {
-    if (pin == NO_PIN) {
+void reset_pin_number(uint8_t pin_port, uint8_t pin_number) {
+    if (pin_port == 0x00) {
         return;
     }
 
     // Clear claimed bit.
-    claimed_pins[gpio_port_num(pin)] &= ~(gpio_mask(pin));
+    claimed_pins[pin_port] &= ~(1<<pin_number);
     // Reset the pin
-    HAL_GPIO_DeInit(ports[gpio_port_num(pin)], gpio_mask(pin));
+    HAL_GPIO_DeInit(ports[pin_port], 1<<pin_number);
 }
 
 
-void never_reset_pin_number(uint8_t pin) {
-    never_reset_pins[gpio_port_num(pin)] |= gpio_mask(pin);
+void never_reset_pin_number(uint8_t pin_port, uint8_t pin_number) {
+    never_reset_pins[pin_port] |= 1<<pin_number;
 }
 
 void claim_pin(const mcu_pin_obj_t* pin) {
     // Set bit in claimed_pins bitmask.
-    claimed_pins[gpio_port_num(pin->number)] |= gpio_mask(pin->number);
+    claimed_pins[pin->port] |= 1<<pin->number;
 }
 
-
-bool pin_number_is_free(uint8_t pin) {
-    return !(claimed_pins[gpio_port_num(pin)] & gpio_mask(pin));
+bool pin_number_is_free(uint8_t pin_port, uint8_t pin_number) {
+    return !(claimed_pins[pin_port] & 1<<pin_number);
 }
 
 bool common_hal_mcu_pin_is_free(const mcu_pin_obj_t *pin) {
-    return pin_number_is_free(pin->number);
+    return pin_number_is_free(pin->port, pin->number);
 }
 
-GPIO_TypeDef * pin_port(uint8_t pin) {
-    return ports[gpio_port_num(pin)];
+GPIO_TypeDef * pin_port(uint8_t pin_port) {
+    return ports[pin_port];
 }
 
-uint16_t pin_mask(uint8_t pin) {
-    return gpio_mask(pin);
+//TODO: replace with macro?
+uint16_t pin_mask(uint8_t pin_number) {
+    return 1<<pin_number;
 }
diff --git a/ports/stm32f4/common-hal/microcontroller/Pin.h b/ports/stm32f4/common-hal/microcontroller/Pin.h
index ca83ef5cf1..0c3fb375f7 100644
--- a/ports/stm32f4/common-hal/microcontroller/Pin.h
+++ b/ports/stm32f4/common-hal/microcontroller/Pin.h
@@ -34,20 +34,11 @@
 void reset_all_pins(void);
 // reset_pin_number takes the pin number instead of the pointer so that objects don't
 // need to store a full pointer.
-void reset_pin_number(uint8_t pin);
+void reset_pin_number(uint8_t pin_port, uint8_t pin_number);
 void claim_pin(const mcu_pin_obj_t* pin);
-bool pin_number_is_free(uint8_t pin);
-void never_reset_pin_number(uint8_t pin);
-void* pin_port(uint8_t pin);
-uint16_t pin_mask(uint8_t pin);
-
-//helper functions for unpacking the pin object "number" into hal-usable addr/mask
-static inline uint8_t gpio_port_num(uint8_t packed_pin) {
-    return packed_pin >> 4;
-}
-
-static inline uint16_t gpio_mask(uint8_t packed_pin) {
-    return 1 << (0x0F & packed_pin);
-}
+bool pin_number_is_free(uint8_t pin_port, uint8_t pin_number);
+void never_reset_pin_number(uint8_t pin_port, uint8_t pin_number);
+GPIO_TypeDef * pin_port(uint8_t pin_port);
+uint16_t pin_mask(uint8_t pin_number);
 
 #endif // MICROPY_INCLUDED_STM34F4_COMMON_HAL_MICROCONTROLLER_PIN_H
diff --git a/ports/stm32f4/peripherals/stm32f4/pins.h b/ports/stm32f4/peripherals/stm32f4/pins.h
index ee11cbe832..2bda672c05 100644
--- a/ports/stm32f4/peripherals/stm32f4/pins.h
+++ b/ports/stm32f4/peripherals/stm32f4/pins.h
@@ -38,8 +38,10 @@
 
 typedef struct {
     mp_obj_base_t base;
-    uint8_t number;
-    uint8_t adc_num_input; //(3)mask ()
+    uint8_t port:4;
+    uint8_t number:4;
+    uint8_t adc_unit:3; 
+    uint8_t adc_channel:5;
 } mcu_pin_obj_t;
 
 #define ADC_1 	1
@@ -49,11 +51,14 @@ typedef struct {
 
 //STM32 ADC pins can have a combination of 1, 2 or all 3 ADCs on a single pin,
 //but all 3 ADCs will share the same input number per pin. 
+//F4 family has 3 ADC max, 24 channels max. 
 #define ADC_INPUT(mask, number) \
-	.adc_num_input = (((mask) << 5) | ((number) & 0x1F)),
+	.adc_unit = mask, \
+	.adc_channel = number,
 
 #define NO_ADC \
-	.adc_num_input = 0xff,
+	.adc_unit = 0x00, \
+	.adc_channel = 0x1f
 
 extern const mp_obj_type_t mcu_pin_type;
 
@@ -62,7 +67,8 @@ extern const mp_obj_type_t mcu_pin_type;
 #define PIN(p_port, p_number, p_adc)       \
 { \
     { &mcu_pin_type }, \
-    .number = (((p_port) << 4) | ((p_number) & 0x0F)), \
+    .port = p_port, \
+    .number = p_number, \
     p_adc \
 }