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TARGET_NRF51_MICROBIT/TARGET_NORDIC/TARGET_MCU_NRF51822/twi_master.h
- Committer:
- jamesadevine
- Date:
- 2016-04-07
- Revision:
- 0:e1a608bb55e8
File content as of revision 0:e1a608bb55e8:
/* 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