adafruit · scath999 · Dec 14, 2021
diff --git a/ports/atmel-samd/common-hal/busio/I2C.c b/ports/atmel-samd/common-hal/busio/I2C.c
@@ -68,7 +68,7 @@ Sercom *samd_i2c_get_sercom(const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda,
 }
 
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
-    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
+    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, bool internal_pullup, uint32_t frequency, uint32_t timeout) {
     uint8_t sercom_index;
     uint32_t sda_pinmux, scl_pinmux;
 

diff --git a/ports/broadcom/common-hal/busio/I2C.c b/ports/broadcom/common-hal/busio/I2C.c
@@ -66,7 +66,7 @@ void reset_i2c(void) {
 }
 
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
-    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
+    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, bool internal_pullup, uint32_t frequency, uint32_t timeout) {
     size_t instance_index = NUM_I2C;
     uint8_t scl_alt = 0;
     uint8_t sda_alt = 0;

diff --git a/ports/cxd56/common-hal/busio/I2C.c b/ports/cxd56/common-hal/busio/I2C.c
@@ -34,7 +34,7 @@
 #include "shared-bindings/busio/I2C.h"
 
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self, const mcu_pin_obj_t *scl,
-    const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
+    const mcu_pin_obj_t *sda, bool internal_pullup, uint32_t frequency, uint32_t timeout) {
     if (frequency != I2C_SPEED_STANDARD && frequency != I2C_SPEED_FAST) {
         mp_raise_ValueError(translate("Unsupported baudrate"));
     }

diff --git a/ports/espressif/common-hal/busio/I2C.c b/ports/espressif/common-hal/busio/I2C.c
@@ -35,7 +35,7 @@
 #include "supervisor/shared/translate.h"
 
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
-    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
+    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, bool internal_pullup, uint32_t frequency, uint32_t timeout) {
     // Pins 45 and 46 are "strapping" pins that impact start up behavior. They usually need to
     // be pulled-down so pulling them up for I2C is a bad idea. To make this hard, we don't
     // support I2C on these pins.

diff --git a/ports/mimxrt10xx/common-hal/busio/I2C.c b/ports/mimxrt10xx/common-hal/busio/I2C.c
@@ -86,7 +86,7 @@ static void i2c_check_pin_config(const mcu_pin_obj_t *pin, uint32_t pull) {
 }
 
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
-    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
+    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, bool internal_pullup, uint32_t frequency, uint32_t timeout) {
 
     #if CIRCUITPY_REQUIRE_I2C_PULLUPS
     // Test that the pins are in a high state. (Hopefully indicating they are pulled up.)

diff --git a/ports/nrf/common-hal/busio/I2C.c b/ports/nrf/common-hal/busio/I2C.c
@@ -94,11 +94,13 @@ static uint8_t twi_error_to_mp(const nrfx_err_t err) {
     return 0;
 }
 
-void common_hal_busio_i2c_construct(busio_i2c_obj_t *self, const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
+void common_hal_busio_i2c_construct(busio_i2c_obj_t *self, const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, bool internal_pullup, uint32_t frequency, uint32_t timeout) {
     if (scl->number == sda->number) {
         mp_raise_ValueError(translate("Invalid pins"));
     }
 
+
+
     // Find a free instance.
     self->twim_peripheral = NULL;
     for (size_t i = 0; i < MP_ARRAY_SIZE(twim_peripherals); i++) {
@@ -126,7 +128,14 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self, const mcu_pin_obj_t *
     // We must pull up within 3us to achieve 400khz.
     common_hal_mcu_delay_us(3);
 
-    if (!nrf_gpio_pin_read(sda->number) || !nrf_gpio_pin_read(scl->number)) {
+    // Set pulls up if internal_pullup is true
+    if (internal_pullup){
+        nrf_gpio_pin_pull_t hal_pull = NRF_GPIO_PIN_PULLUP;
+
+        nrf_gpio_cfg_input(scl->number, hal_pull);
+        nrf_gpio_cfg_input(sda->number, hal_pull);
+    }
+    else if (!nrf_gpio_pin_read(sda->number) || !nrf_gpio_pin_read(scl->number)) {
         reset_pin_number(sda->number);
         reset_pin_number(scl->number);
         mp_raise_RuntimeError(translate("No pull up found on SDA or SCL; check your wiring"));

diff --git a/ports/nrf/mpconfigport.mk b/ports/nrf/mpconfigport.mk
@@ -83,6 +83,7 @@ ifeq ($(MCU_CHIP),nrf52833)
 MCU_SERIES = m4
 MCU_VARIANT = nrf52
 MCU_SUB_VARIANT = nrf52833
+CIRCUITPY_INTERNAL_PULLUPS = 1
 
 SD ?= s140
 SOFTDEV_VERSION ?= 7.0.1

diff --git a/ports/raspberrypi/common-hal/busio/I2C.c b/ports/raspberrypi/common-hal/busio/I2C.c
@@ -55,7 +55,7 @@ void reset_i2c(void) {
 }
 
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
-    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
+    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, bool internal_pullup, uint32_t frequency, uint32_t timeout) {
     self->peripheral = NULL;
     // I2C pins have a regular pattern. SCL is always odd and SDA is even. They match up in pairs
     // so we can divide by two to get the instance. This pattern repeats.
@@ -92,7 +92,14 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
     // We must pull up within 3us to achieve 400khz.
     common_hal_mcu_delay_us(3);
 
-    if (!gpio_get(sda->number) || !gpio_get(scl->number)) {
+    // Set pulls up if internal_pullup is true
+    if (internal_pullup){
+        nrf_gpio_pin_pull_t hal_pull = NRF_GPIO_PIN_PULLUP;
+
+        nrf_gpio_cfg_input(scl->number, hal_pull);
+        nrf_gpio_cfg_input(sda->number, hal_pull);
+    }
+    else if (!nrf_gpio_pin_read(sda->number) || !nrf_gpio_pin_read(scl->number)) {
         reset_pin_number(sda->number);
         reset_pin_number(scl->number);
         mp_raise_RuntimeError(translate("No pull up found on SDA or SCL; check your wiring"));
@@ -112,7 +119,7 @@ void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
     //
     // Do not use the default supplied clock stretching timeout here.
     // It is too short for some devices. Use the busio timeout instead.
-    shared_module_bitbangio_i2c_construct(&self->bitbangio_i2c, scl, sda,
+    shared_module_bitbangio_i2c_construct(&self->bitbangio_i2c, scl, sda, internal_pullup,
         frequency, BUS_TIMEOUT_US);
 
     self->baudrate = i2c_init(self->peripheral, frequency);

diff --git a/ports/stm/common-hal/busio/I2C.c b/ports/stm/common-hal/busio/I2C.c
@@ -83,7 +83,7 @@ void i2c_reset(void) {
 }
 
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
-    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t frequency, uint32_t timeout) {
+    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, bool internal_pullup, uint32_t frequency, uint32_t timeout) {
 
     // Match pins to I2C objects
     I2C_TypeDef *I2Cx;

diff --git a/py/circuitpy_mpconfig.h b/py/circuitpy_mpconfig.h
@@ -276,6 +276,13 @@ typedef long mp_off_t;
 #define BOARD_UART_ROOT_POINTER
 #endif
 
+// Support for internal pullups for boards that have them: e.g. nrf52833
+#if CIRCUITPY_INTERNAL_PULLUPS
+#define HAS_INTERNAL_PULLUPS = true
+#else
+#define HAS_INTERNAL_PULLUPS = false
+#endif
+
 #if CIRCUITPY_DISPLAYIO
 #ifndef CIRCUITPY_DISPLAY_LIMIT
 #define CIRCUITPY_DISPLAY_LIMIT (1)

diff --git a/py/circuitpy_mpconfig.mk b/py/circuitpy_mpconfig.mk
@@ -462,3 +462,7 @@ CFLAGS += -DCIRCUITPY_WATCHDOG=$(CIRCUITPY_WATCHDOG)
 
 CIRCUITPY_WIFI ?= 0
 CFLAGS += -DCIRCUITPY_WIFI=$(CIRCUITPY_WIFI)
+
+# support for internal pullups
+CIRCUITPY_INTERNAL_PULLUPS ?= 0
+CFLAGS += -DCIRCUITPY_INTERNAL_PULLUPS=$(CIRCUITPY_INTERNAL_PULLUPS)
diff --git a/shared-bindings/bitbangio/I2C.c b/shared-bindings/bitbangio/I2C.c
@@ -55,6 +55,7 @@
 //|
 //|         :param ~microcontroller.Pin scl: The clock pin
 //|         :param ~microcontroller.Pin sda: The data pin
+//|         :param bool internal_pullups: Set pulls on each pin to up if board supports internal pullups - defaults to false
 //|         :param int frequency: The clock frequency of the bus
 //|         :param int timeout: The maximum clock stretching timeout in microseconds"""
 //|         ...
@@ -64,6 +65,7 @@ STATIC mp_obj_t bitbangio_i2c_make_new(const mp_obj_type_t *type, size_t n_args,
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_scl, MP_ARG_REQUIRED | MP_ARG_OBJ },
         { MP_QSTR_sda, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_internal_pullup, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false}  }, 
         { MP_QSTR_frequency, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 400000} },
         { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 255} },
     };
@@ -75,7 +77,7 @@ STATIC mp_obj_t bitbangio_i2c_make_new(const mp_obj_type_t *type, size_t n_args,
 
     bitbangio_i2c_obj_t *self = m_new_obj(bitbangio_i2c_obj_t);
     self->base.type = &bitbangio_i2c_type;
-    shared_module_bitbangio_i2c_construct(self, scl, sda, args[ARG_frequency].u_int, args[ARG_timeout].u_int);
+    shared_module_bitbangio_i2c_construct(self, scl, sda, args[ARG_internal_pullup].u_int, args[ARG_frequency].u_int, args[ARG_timeout].u_int);
     return (mp_obj_t)self;
 }
 

diff --git a/shared-bindings/bitbangio/I2C.h b/shared-bindings/bitbangio/I2C.h
@@ -39,6 +39,7 @@ extern const mp_obj_type_t bitbangio_i2c_type;
 extern void shared_module_bitbangio_i2c_construct(bitbangio_i2c_obj_t *self,
     const mcu_pin_obj_t *scl,
     const mcu_pin_obj_t *sda,
+    bool internal_pullup,
     uint32_t frequency,
     uint32_t us_timeout);
 

diff --git a/shared-bindings/busio/I2C.c b/shared-bindings/busio/I2C.c
@@ -55,6 +55,7 @@
 //|
 //|         :param ~microcontroller.Pin scl: The clock pin
 //|         :param ~microcontroller.Pin sda: The data pin
+//|         :param bool internal_pullups: Set pulls on each pin to up if board supports internal pullups - defaults to false
 //|         :param int frequency: The clock frequency in Hertz
 //|         :param int timeout: The maximum clock stretching timeut - (used only for
 //|             :class:`bitbangio.I2C`; ignored for :class:`busio.I2C`)
@@ -67,10 +68,11 @@
 STATIC mp_obj_t busio_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
     busio_i2c_obj_t *self = m_new_obj(busio_i2c_obj_t);
     self->base.type = &busio_i2c_type;
-    enum { ARG_scl, ARG_sda, ARG_frequency, ARG_timeout };
+    enum { ARG_scl, ARG_sda, ARG_internal_pullup, ARG_frequency, ARG_timeout };
     static const mp_arg_t allowed_args[] = {
         { MP_QSTR_scl, MP_ARG_REQUIRED | MP_ARG_OBJ },
         { MP_QSTR_sda, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_internal_pullup, MP_ARG_KW_ONLY | MP_ARG_BOOL, {.u_bool = false}  }, 
         { MP_QSTR_frequency, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 100000} },
         { MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 255} },
     };
@@ -80,7 +82,7 @@ STATIC mp_obj_t busio_i2c_make_new(const mp_obj_type_t *type, size_t n_args, siz
     const mcu_pin_obj_t *scl = validate_obj_is_free_pin(args[ARG_scl].u_obj);
     const mcu_pin_obj_t *sda = validate_obj_is_free_pin(args[ARG_sda].u_obj);
 
-    common_hal_busio_i2c_construct(self, scl, sda, args[ARG_frequency].u_int, args[ARG_timeout].u_int);
+    common_hal_busio_i2c_construct(self, scl, sda, args[ARG_internal_pullup].u_int, args[ARG_frequency].u_int, args[ARG_timeout].u_int);
     return (mp_obj_t)self;
 }
 

diff --git a/shared-bindings/busio/I2C.h b/shared-bindings/busio/I2C.h
@@ -46,6 +46,7 @@ extern const mp_obj_type_t busio_i2c_type;
 extern void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
     const mcu_pin_obj_t *scl,
     const mcu_pin_obj_t *sda,
+    bool internal_pullup,
     uint32_t frequency,
     uint32_t timeout);
 

diff --git a/shared-module/bitbangio/I2C.c b/shared-module/bitbangio/I2C.c
@@ -145,6 +145,7 @@ STATIC bool read_byte(bitbangio_i2c_obj_t *self, uint8_t *val, bool ack) {
 void shared_module_bitbangio_i2c_construct(bitbangio_i2c_obj_t *self,
     const mcu_pin_obj_t *scl,
     const mcu_pin_obj_t *sda,
+    bool internal_pullup,
     uint32_t frequency,
     uint32_t us_timeout) {
 

diff --git a/shared-module/board/__init__.c b/shared-module/board/__init__.c
@@ -62,7 +62,7 @@ mp_obj_t common_hal_board_create_i2c(void) {
     busio_i2c_obj_t *self = &i2c_obj;
     self->base.type = &busio_i2c_type;
 
-    common_hal_busio_i2c_construct(self, DEFAULT_I2C_BUS_SCL, DEFAULT_I2C_BUS_SDA, 100000, 255);
+    common_hal_busio_i2c_construct(self, DEFAULT_I2C_BUS_SCL, DEFAULT_I2C_BUS_SDA, HAS_INTERNAL_PULLUPS, 100000, 255);
     i2c_singleton = (mp_obj_t)self;
     return i2c_singleton;
 }

diff --git a/shared-module/busio/I2C.c b/shared-module/busio/I2C.c
@@ -30,7 +30,7 @@
 #include "py/nlr.h"
 
 void common_hal_busio_i2c_construct(busio_i2c_obj_t *self,
-    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, uint32_t freq, uint32_t timeout) {
+    const mcu_pin_obj_t *scl, const mcu_pin_obj_t *sda, bool internal_pullup, uint32_t freq, uint32_t timeout) {
     shared_module_bitbangio_i2c_construct(&self->bitbang, scl, sda, freq, timeout);
 }