diff --git a/boards/acd52832/include/periph_conf.h b/boards/acd52832/include/periph_conf.h
index a2703046f7692b7a8253c4d10b9f2e47fd162a09..d1223e4902985e3dcc74d7f36fb15f71c8956c0b 100644
--- a/boards/acd52832/include/periph_conf.h
+++ b/boards/acd52832/include/periph_conf.h
@@ -96,6 +96,21 @@ static const spi_conf_t spi_config[] = {
#define SPI_NUMOF (sizeof(spi_config) / sizeof(spi_config[0]))
/** @} */
+/**
+ * @name I2C configuration
+ * @{
+ */
+static const i2c_conf_t i2c_config[] = {
+ {
+ .dev = NRF_TWIM0,
+ .pin_scl = 28,
+ .pin_sda = 29
+ }
+};
+
+#define I2C_NUMOF (sizeof(i2c_config) / sizeof(i2c_config[0]))
+/** @} */
+
#ifdef __cplusplus
}
#endif
diff --git a/boards/common/nrf52xxxdk/Makefile.features b/boards/common/nrf52xxxdk/Makefile.features
index 5c594d4b0d28674f1c3095de7147c70c20262bb2..56ed0022c03b13df2b60ce2c12b0963bfefcafc7 100644
--- a/boards/common/nrf52xxxdk/Makefile.features
+++ b/boards/common/nrf52xxxdk/Makefile.features
@@ -1,5 +1,6 @@
# Put defined MCU peripherals here (in alphabetical order)
FEATURES_PROVIDED += periph_gpio
+FEATURES_PROVIDED += periph_i2c
FEATURES_PROVIDED += periph_rtt
FEATURES_PROVIDED += periph_spi
FEATURES_PROVIDED += periph_timer
diff --git a/boards/common/nrf52xxxdk/include/periph_conf.h b/boards/common/nrf52xxxdk/include/periph_conf.h
index 4242273a3b80a1e757fadedaa99b4243ffbc4bbf..de3202a230cd30e53ff0a21b89f55d9b3ee086f2 100644
--- a/boards/common/nrf52xxxdk/include/periph_conf.h
+++ b/boards/common/nrf52xxxdk/include/periph_conf.h
@@ -93,6 +93,21 @@ static const spi_conf_t spi_config[] = {
#define SPI_NUMOF (sizeof(spi_config) / sizeof(spi_config[0]))
/** @} */
+/**
+ * @name I2C configuration
+ * @{
+ */
+static const i2c_conf_t i2c_config[] = {
+ {
+ .dev = NRF_TWIM0,
+ .pin_scl = 28,
+ .pin_sda = 29
+ }
+};
+
+#define I2C_NUMOF (sizeof(i2c_config) / sizeof(i2c_config[0]))
+/** @} */
+
#ifdef __cplusplus
}
#endif
diff --git a/cpu/nrf52/include/periph_cpu.h b/cpu/nrf52/include/periph_cpu.h
index bac6b6487e7c8d310ded0c09efe5b846338108a8..8614621958eac2b872d478d5a318384d787e6d45 100644
--- a/cpu/nrf52/include/periph_cpu.h
+++ b/cpu/nrf52/include/periph_cpu.h
@@ -75,6 +75,29 @@ typedef enum {
} adc_res_t;
/** @} */
+/**
+ * @brief Override I2C speed settings
+ * @{
+ */
+#define HAVE_I2C_SPEED_T
+typedef enum {
+ I2C_SPEED_LOW = 0xff, /**< not supported */
+ I2C_SPEED_NORMAL = TWI_FREQUENCY_FREQUENCY_K100, /**< 100kbit/s */
+ I2C_SPEED_FAST = TWI_FREQUENCY_FREQUENCY_K400, /**< 400kbit/s */
+ I2C_SPEED_FAST_PLUS = 0xfe, /**< not supported */
+ I2C_SPEED_HIGH = 0xfd, /**< not supported */
+} i2c_speed_t;
+/** @} */
+
+/**
+ * @brief I2C (TWI) configuration options
+ */
+typedef struct {
+ NRF_TWIM_Type *dev; /**< hardware device */
+ uint8_t pin_scl; /**< SCL pin */
+ uint8_t pin_sda; /**< SDA pin */
+} i2c_conf_t;
+
#ifdef __cplusplus
}
#endif
diff --git a/cpu/nrf52/periph/i2c.c b/cpu/nrf52/periph/i2c.c
new file mode 100644
index 0000000000000000000000000000000000000000..b8d681fdeb1a1ab1755fe392de2f3ac8e7d3f15f
--- /dev/null
+++ b/cpu/nrf52/periph/i2c.c
@@ -0,0 +1,209 @@
+/*
+ * Copyright (C) 2017 HAW Hamburg
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @ingroup cpu_nrf52
+ * @{
+ *
+ * @file
+ * @brief Low-level I2C driver implementation
+ *
+ * @author Dimitri Nahm <dimitri.nahm@haw-hamburg.de>
+ *
+ * @}
+ */
+
+#include "cpu.h"
+#include "mutex.h"
+#include "assert.h"
+#include "periph/i2c.h"
+#include "periph_conf.h"
+
+#define ENABLE_DEBUG (0)
+#include "debug.h"
+
+/**
+ * @brief If any of the 4 lower bits are set, the speed value is invalid
+ */
+#define INVALID_SPEED_MASK (0x0f)
+
+static mutex_t locks[I2C_NUMOF];
+
+static inline NRF_TWIM_Type *dev(i2c_t bus)
+{
+ return i2c_config[bus].dev;
+}
+
+static int error(i2c_t bus)
+{
+ DEBUG("[i2c] error 0x%02x\n", (int)dev(bus)->ERRORSRC);
+ dev(bus)->ERRORSRC = 0;
+ dev(bus)->EVENTS_ERROR = 0;
+ return -1;
+}
+
+static int write(i2c_t bus, uint8_t address, const void *data, int length, int stop)
+{
+ uint8_t *out_buf = (uint8_t *)data;
+ assert((bus <= I2C_NUMOF) && (length > 0));
+
+ DEBUG("[i2c]: writing %i bytes to the bus\n", length);
+
+ /* disable shortcuts */
+ if (stop == 0) {
+ dev(bus)->SHORTS = 0;
+ }
+
+ /* set the client address and the data pointer */
+ dev(bus)->ADDRESS = (address & 0x7f);
+ dev(bus)->TXD.PTR = (uint32_t)out_buf;
+ dev(bus)->TXD.MAXCNT = (length << TWIM_TXD_MAXCNT_MAXCNT_Pos);
+
+ /* start write sequence */
+ dev(bus)->EVENTS_LASTTX = 0;
+ dev(bus)->TASKS_STARTTX = 1;
+
+ /* wait for the device to finish up */
+ while ((dev(bus)->EVENTS_LASTTX == 0) && (dev(bus)->EVENTS_ERROR == 0)) {}
+ if (dev(bus)->EVENTS_ERROR) {
+ return error(bus);
+ }
+
+ /* wait for the device to finish up */
+ while ((dev(bus)->TXD.AMOUNT != (unsigned)length) && (dev(bus)->EVENTS_ERROR == 0)) {}
+ if (dev(bus)->EVENTS_ERROR) {
+ return error(bus);
+ }
+
+ /* enable shortcuts */
+ if (stop == 0) {
+ dev(bus)->SHORTS = (TWIM_SHORTS_LASTTX_STOP_Enabled << TWIM_SHORTS_LASTTX_STOP_Pos) |
+ (TWIM_SHORTS_LASTRX_STOP_Enabled << TWIM_SHORTS_LASTRX_STOP_Pos);
+ }
+
+ return dev(bus)->TXD.AMOUNT;
+}
+
+int i2c_init_master(i2c_t bus, i2c_speed_t speed)
+{
+ if (bus >= I2C_NUMOF) {
+ return -1;
+ }
+ if (speed & INVALID_SPEED_MASK) {
+ return -2;
+ }
+
+ /* initialize lock */
+ mutex_init(&locks[bus]);
+
+ /* pin configuration */
+ NRF_P0->PIN_CNF[i2c_config[bus].pin_scl] = (GPIO_PIN_CNF_DRIVE_S0D1 << GPIO_PIN_CNF_DRIVE_Pos);
+ NRF_P0->PIN_CNF[i2c_config[bus].pin_scl] = (GPIO_PIN_CNF_DRIVE_S0D1 << GPIO_PIN_CNF_DRIVE_Pos);
+ dev(bus)->PSEL.SCL = i2c_config[bus].pin_scl;
+ dev(bus)->PSEL.SDA = i2c_config[bus].pin_sda;
+
+ /* shortcuts configuration */
+ dev(bus)->SHORTS = (TWIM_SHORTS_LASTTX_STOP_Enabled << TWIM_SHORTS_LASTTX_STOP_Pos) |
+ (TWIM_SHORTS_LASTRX_STOP_Enabled << TWIM_SHORTS_LASTRX_STOP_Pos);
+
+ /* bus clock speed configuration */
+ dev(bus)->FREQUENCY = (speed << TWIM_FREQUENCY_FREQUENCY_Pos);
+
+ /* enable the device */
+ dev(bus)->ENABLE = (TWIM_ENABLE_ENABLE_Enabled << TWIM_ENABLE_ENABLE_Pos);
+
+ return 0;
+}
+
+int i2c_acquire(i2c_t bus)
+{
+ assert(bus <= I2C_NUMOF);
+ mutex_lock(&locks[bus]);
+ return 0;
+}
+
+int i2c_release(i2c_t bus)
+{
+ assert(bus <= I2C_NUMOF);
+ mutex_unlock(&locks[bus]);
+ return 0;
+}
+
+int i2c_read_byte(i2c_t bus, uint8_t address, void *data)
+{
+ return i2c_read_bytes(bus, address, data, 1);
+}
+
+int i2c_read_bytes(i2c_t bus, uint8_t address, void *data, int length)
+{
+ uint8_t *in_buf = (uint8_t *)data;
+ assert((bus <= I2C_NUMOF) && (length > 0));
+
+ DEBUG("[i2c] reading %i bytes from the bus\n", length);
+
+ /* set the client address and the data pointer */
+ dev(bus)->ADDRESS = (address & 0x7f);
+ dev(bus)->RXD.PTR = (uint32_t)in_buf;
+ dev(bus)->RXD.MAXCNT = (length << TWIM_RXD_MAXCNT_MAXCNT_Pos);
+
+ /* start read sequence */
+ dev(bus)->EVENTS_STOPPED = 0;
+ dev(bus)->TASKS_STARTRX = 1;
+
+ /* wait for the device to finish up */
+ while ((dev(bus)->EVENTS_STOPPED == 0) && (dev(bus)->EVENTS_ERROR == 0)) {}
+ if (dev(bus)->EVENTS_ERROR) {
+ return error(bus);
+ }
+
+ return dev(bus)->RXD.AMOUNT;
+}
+
+int i2c_read_reg(i2c_t bus, uint8_t address, uint8_t reg, void *data)
+{
+ write(bus, address, ®, 1, 0);
+ return i2c_read_bytes(bus, address, data, 1);
+}
+
+int i2c_read_regs(i2c_t bus, uint8_t address, uint8_t reg,
+ void *data, int length)
+{
+ write(bus, address, ®, 1, 0);
+ return i2c_read_bytes(bus, address, data, length);
+}
+
+int i2c_write_byte(i2c_t bus, uint8_t address, uint8_t data)
+{
+ return write(bus, address, &data, 1, 1);
+}
+
+int i2c_write_bytes(i2c_t bus, uint8_t address, const void *data, int length)
+{
+ return write(bus, address, data, length, 1);
+}
+
+int i2c_write_reg(i2c_t bus, uint8_t address, uint8_t reg, uint8_t data)
+{
+ /* send reg and data in one function call */
+ uint8_t out_buf[2];
+ out_buf[0] = reg;
+ out_buf[1] = data;
+ return write(bus, address, &out_buf, 2, 1) - 1;
+}
+
+int i2c_write_regs(i2c_t bus, uint8_t address, uint8_t reg, const void *data, int length)
+{
+ /* send reg and data in one function call */
+ uint8_t *buf = (uint8_t *)data;
+ uint8_t out_buf[length + 1];
+ out_buf[0] = reg;
+ for (int i = 0; i < length ; i++) {
+ out_buf[i + 1] = buf[i];
+ }
+ return write(bus, address, &out_buf, (length + 1), 1) - 1;
+}