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Diff: TARGET_NRF51_MICROBIT/TARGET_NORDIC/TARGET_MCU_NRF51822/twi_master.h
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/TARGET_NRF51_MICROBIT/TARGET_NORDIC/TARGET_MCU_NRF51822/twi_master.h Thu Apr 07 18:33:58 2016 +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