mirror of https://github.com/ARMmbed/mbed-os.git
113 lines
4.7 KiB
C
113 lines
4.7 KiB
C
/* Copyright (c) 2009 Nordic Semiconductor. All Rights Reserved.
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*
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* The information contained herein is property of Nordic Semiconductor ASA.
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* Terms and conditions of usage are described in detail in NORDIC
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* SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
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*
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* Licensees are granted free, non-transferable use of the information. NO
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* WARRANTY of ANY KIND is provided. This heading must NOT be removed from
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* the file.
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*
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*/
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#ifndef TWI_MASTER_H
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#define TWI_MASTER_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*lint ++flb "Enter library region" */
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#include <stdbool.h>
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#include <stdint.h>
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#include "nrf51.h"
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/** @file
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* @brief Software controlled TWI Master driver.
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*
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*
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* @defgroup lib_driver_twi_master Software controlled TWI Master driver
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* @{
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* @ingroup nrf_drivers
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* @brief Software controlled TWI Master driver.
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*
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* Supported features:
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* - Repeated start
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* - No multi-master
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* - Only 7-bit addressing
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* - Supports clock stretching (with optional SMBus style slave timeout)
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* - Tries to handle slaves stuck in the middle of transfer
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*/
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#define TWI_READ_BIT (0x01) //!< If this bit is set in the address field, transfer direction is from slave to master.
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#define TWI_ISSUE_STOP ((bool)true) //!< Parameter for @ref twi_master_transfer
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#define TWI_DONT_ISSUE_STOP ((bool)false) //!< Parameter for @ref twi_master_transfer
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/* These macros are needed to see if the slave is stuck and we as master send dummy clock cycles to end its wait */
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/*lint -e717 -save "Suppress do {} while (0) for these macros" */
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/*lint ++flb "Enter library region" */
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#define TWI_SCL_HIGH() do { NRF_GPIO->OUTSET = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0) /*!< Pulls SCL line high */
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#define TWI_SCL_LOW() do { NRF_GPIO->OUTCLR = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0) /*!< Pulls SCL line low */
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#define TWI_SDA_HIGH() do { NRF_GPIO->OUTSET = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER); } while(0) /*!< Pulls SDA line high */
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#define TWI_SDA_LOW() do { NRF_GPIO->OUTCLR = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER); } while(0) /*!< Pulls SDA line low */
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#define TWI_SDA_INPUT() do { NRF_GPIO->DIRCLR = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER); } while(0) /*!< Configures SDA pin as input */
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#define TWI_SDA_OUTPUT() do { NRF_GPIO->DIRSET = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER); } while(0) /*!< Configures SDA pin as output */
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#define TWI_SCL_OUTPUT() do { NRF_GPIO->DIRSET = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0) /*!< Configures SCL pin as output */
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/*lint -restore */
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#define TWI_SDA_READ() ((NRF_GPIO->IN >> TWI_MASTER_CONFIG_DATA_PIN_NUMBER) & 0x1UL) /*!< Reads current state of SDA */
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#define TWI_SCL_READ() ((NRF_GPIO->IN >> TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER) & 0x1UL) /*!< Reads current state of SCL */
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#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. */
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/**
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* @brief Function for initializing TWI bus IO pins and checks if the bus is operational.
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*
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* Both pins are configured as Standard-0, No-drive-1 (open drain).
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*
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* @param twi The TWI interface to use - either NRF_TWI0 or NRF_TWI1
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* @return
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* @retval true TWI bus is clear for transfers.
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* @retval false TWI bus is stuck.
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*/
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bool twi_master_init_and_clear(NRF_TWI_Type* twi);
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/**
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* @brief Function for transferring data over TWI bus.
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*
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* If TWI master detects even one NACK from the slave or timeout occurs, STOP condition is issued
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* and the function returns false.
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* Bit 0 (@ref TWI_READ_BIT) in the address parameter controls transfer direction;
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* - If 1, master reads data_length number of bytes from the slave
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* - If 0, master writes data_length number of bytes to the slave.
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*
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* @note Make sure at least data_length number of bytes is allocated in data if TWI_READ_BIT is set.
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* @note @ref TWI_ISSUE_STOP
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*
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* @param address Data transfer direction (LSB) / Slave address (7 MSBs).
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* @param data Pointer to data.
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* @param data_length Number of bytes to transfer.
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* @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.
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* @param twi The TWI interface to use - either NRF_TWI0 or NRF_TWI1
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* @return
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* @retval true Data transfer succeeded without errors.
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* @retval false Data transfer failed.
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*/
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bool twi_master_transfer(uint8_t address, uint8_t *data, uint8_t data_length, bool issue_stop_condition, NRF_TWI_Type* twi);
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/**
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*@}
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**/
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#ifdef __cplusplus
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}
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#endif
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/*lint --flb "Leave library region" */
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#endif //TWI_MASTER_H
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