Diff: targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/twi_master.h

Revision:

598:2d5fc5624619

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/twi_master.h	Wed Jul 29 09:45:09 2015 +0100
@@ -0,0 +1,108 @@
+ /* Copyright (c) 2009 Nordic Semiconductor. All Rights Reserved.
+ *
+ * The information contained herein is property of Nordic Semiconductor ASA.
+ * Terms and conditions of usage are described in detail in NORDIC
+ * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
+ *
+ * Licensees are granted free, non-transferable use of the information. NO
+ * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
+ * the file.
+ *
+ */
+
+#ifndef TWI_MASTER_H
+#define TWI_MASTER_H
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*lint ++flb "Enter library region" */
+
+#include <stdbool.h>
+#include <stdint.h>
+
+/** @file
+* @brief Software controlled TWI Master driver.
+*
+*
+* @defgroup lib_driver_twi_master Software controlled TWI Master driver
+* @{
+* @ingroup nrf_drivers
+* @brief Software controlled TWI Master driver.
+*
+* Supported features:
+* - Repeated start
+* - No multi-master
+* - Only 7-bit addressing
+* - Supports clock stretching (with optional SMBus style slave timeout)
+* - Tries to handle slaves stuck in the middle of transfer
+*/
+
+#define TWI_READ_BIT                 (0x01)        //!< If this bit is set in the address field, transfer direction is from slave to master.
+
+#define TWI_ISSUE_STOP               ((bool)true)  //!< Parameter for @ref twi_master_transfer
+#define TWI_DONT_ISSUE_STOP          ((bool)false) //!< Parameter for @ref twi_master_transfer
+
+/* These macros are needed to see if the slave is stuck and we as master send dummy clock cycles to end its wait */
+/*lint -e717 -save "Suppress do {} while (0) for these macros" */
+/*lint ++flb "Enter library region" */
+#define TWI_SCL_HIGH()   do { NRF_GPIO->OUTSET = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0)   /*!< Pulls SCL line high */
+#define TWI_SCL_LOW()    do { NRF_GPIO->OUTCLR = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0)   /*!< Pulls SCL line low  */
+#define TWI_SDA_HIGH()   do { NRF_GPIO->OUTSET = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER);  } while(0)   /*!< Pulls SDA line high */
+#define TWI_SDA_LOW()    do { NRF_GPIO->OUTCLR = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER);  } while(0)   /*!< Pulls SDA line low  */
+#define TWI_SDA_INPUT()  do { NRF_GPIO->DIRCLR = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER);  } while(0)   /*!< Configures SDA pin as input  */
+#define TWI_SDA_OUTPUT() do { NRF_GPIO->DIRSET = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER);  } while(0)   /*!< Configures SDA pin as output */
+#define TWI_SCL_OUTPUT() do { NRF_GPIO->DIRSET = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0)   /*!< Configures SCL pin as output */
+/*lint -restore */
+
+#define TWI_SDA_READ() ((NRF_GPIO->IN >> TWI_MASTER_CONFIG_DATA_PIN_NUMBER) & 0x1UL)                     /*!< Reads current state of SDA */
+#define TWI_SCL_READ() ((NRF_GPIO->IN >> TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER) & 0x1UL)                    /*!< Reads current state of SCL */
+
+#define TWI_DELAY() nrf_delay_us(4) /*!< Time to wait when pin states are changed. For fast-mode the delay can be zero and for standard-mode 4 us delay is sufficient. */
+
+
+/**
+ * @brief Function for initializing TWI bus IO pins and checks if the bus is operational.
+ *
+ * Both pins are configured as Standard-0, No-drive-1 (open drain).
+ *
+ * @return
+ * @retval true TWI bus is clear for transfers.
+ * @retval false TWI bus is stuck.
+ */
+bool twi_master_init_and_clear(void);
+
+/**
+ * @brief Function for transferring data over TWI bus.
+ *
+ * If TWI master detects even one NACK from the slave or timeout occurs, STOP condition is issued
+ * and the function returns false.
+ * Bit 0 (@ref TWI_READ_BIT) in the address parameter controls transfer direction;
+ * - If 1, master reads data_length number of bytes from the slave
+ * - If 0, master writes data_length number of bytes to the slave.
+ *
+ * @note Make sure at least data_length number of bytes is allocated in data if TWI_READ_BIT is set.
+ * @note @ref TWI_ISSUE_STOP
+ *
+ * @param address Data transfer direction (LSB) / Slave address (7 MSBs).
+ * @param data Pointer to data.
+ * @param data_length Number of bytes to transfer.
+ * @param issue_stop_condition If @ref TWI_ISSUE_STOP, STOP condition is issued before exiting function. If @ref TWI_DONT_ISSUE_STOP, STOP condition is not issued before exiting function. If transfer failed for any reason, STOP condition will be issued in any case.
+ * @return
+ * @retval true Data transfer succeeded without errors.
+ * @retval false Data transfer failed.
+ */
+bool twi_master_transfer(uint8_t address, uint8_t *data, uint8_t data_length, bool issue_stop_condition);
+
+/**
+ *@}
+ **/
+
+#ifdef __cplusplus
+}
+#endif
+
+/*lint --flb "Leave library region" */
+#endif //TWI_MASTER_H