Giovanni Bauermeister / mbed-dev-bin

example micro:bit pedometer

Fork of mbed-dev-bin by Lancaster University

TARGET_NRF51_MICROBIT/TARGET_NORDIC/TARGET_MCU_NRF51822/twi_master.h@4:084689a02e93, 2018-04-27 (annotated)

Committer:
giobauermeister
Date:
Fri Apr 27 12:59:57 2018 +0000
Revision:
4:084689a02e93
Parent:
0:e1a608bb55e8 
example micro:bit pedometer

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jamesadevine 0:e1a608bb55e8 1 /* Copyright (c) 2009 Nordic Semiconductor. All Rights Reserved.
jamesadevine 0:e1a608bb55e8 2 *
jamesadevine 0:e1a608bb55e8 3 * The information contained herein is property of Nordic Semiconductor ASA.
jamesadevine 0:e1a608bb55e8 4 * Terms and conditions of usage are described in detail in NORDIC
jamesadevine 0:e1a608bb55e8 5 * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
jamesadevine 0:e1a608bb55e8 6 *
jamesadevine 0:e1a608bb55e8 7 * Licensees are granted free, non-transferable use of the information. NO
jamesadevine 0:e1a608bb55e8 8 * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
jamesadevine 0:e1a608bb55e8 9 * the file.
jamesadevine 0:e1a608bb55e8 10 *
jamesadevine 0:e1a608bb55e8 11 */
jamesadevine 0:e1a608bb55e8 12
jamesadevine 0:e1a608bb55e8 13 #ifndef TWI_MASTER_H
jamesadevine 0:e1a608bb55e8 14 #define TWI_MASTER_H
jamesadevine 0:e1a608bb55e8 15
jamesadevine 0:e1a608bb55e8 16
jamesadevine 0:e1a608bb55e8 17 #ifdef __cplusplus
jamesadevine 0:e1a608bb55e8 18 extern "C" {
jamesadevine 0:e1a608bb55e8 19 #endif
jamesadevine 0:e1a608bb55e8 20
jamesadevine 0:e1a608bb55e8 21 /*lint ++flb "Enter library region" */
jamesadevine 0:e1a608bb55e8 22
jamesadevine 0:e1a608bb55e8 23 #include <stdbool.h>
jamesadevine 0:e1a608bb55e8 24 #include <stdint.h>
jamesadevine 0:e1a608bb55e8 25
jamesadevine 0:e1a608bb55e8 26 /** @file
jamesadevine 0:e1a608bb55e8 27 * @brief Software controlled TWI Master driver.
jamesadevine 0:e1a608bb55e8 28 *
jamesadevine 0:e1a608bb55e8 29 *
jamesadevine 0:e1a608bb55e8 30 * @defgroup lib_driver_twi_master Software controlled TWI Master driver
jamesadevine 0:e1a608bb55e8 31 * @{
jamesadevine 0:e1a608bb55e8 32 * @ingroup nrf_drivers
jamesadevine 0:e1a608bb55e8 33 * @brief Software controlled TWI Master driver.
jamesadevine 0:e1a608bb55e8 34 *
jamesadevine 0:e1a608bb55e8 35 * Supported features:
jamesadevine 0:e1a608bb55e8 36 * - Repeated start
jamesadevine 0:e1a608bb55e8 37 * - No multi-master
jamesadevine 0:e1a608bb55e8 38 * - Only 7-bit addressing
jamesadevine 0:e1a608bb55e8 39 * - Supports clock stretching (with optional SMBus style slave timeout)
jamesadevine 0:e1a608bb55e8 40 * - Tries to handle slaves stuck in the middle of transfer
jamesadevine 0:e1a608bb55e8 41 */
jamesadevine 0:e1a608bb55e8 42
jamesadevine 0:e1a608bb55e8 43 #define TWI_READ_BIT (0x01) //!< If this bit is set in the address field, transfer direction is from slave to master.
jamesadevine 0:e1a608bb55e8 44
jamesadevine 0:e1a608bb55e8 45 #define TWI_ISSUE_STOP ((bool)true) //!< Parameter for @ref twi_master_transfer
jamesadevine 0:e1a608bb55e8 46 #define TWI_DONT_ISSUE_STOP ((bool)false) //!< Parameter for @ref twi_master_transfer
jamesadevine 0:e1a608bb55e8 47
jamesadevine 0:e1a608bb55e8 48 /* These macros are needed to see if the slave is stuck and we as master send dummy clock cycles to end its wait */
jamesadevine 0:e1a608bb55e8 49 /*lint -e717 -save "Suppress do {} while (0) for these macros" */
jamesadevine 0:e1a608bb55e8 50 /*lint ++flb "Enter library region" */
jamesadevine 0:e1a608bb55e8 51 #define TWI_SCL_HIGH() do { NRF_GPIO->OUTSET = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0) /*!< Pulls SCL line high */
jamesadevine 0:e1a608bb55e8 52 #define TWI_SCL_LOW() do { NRF_GPIO->OUTCLR = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0) /*!< Pulls SCL line low */
jamesadevine 0:e1a608bb55e8 53 #define TWI_SDA_HIGH() do { NRF_GPIO->OUTSET = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER); } while(0) /*!< Pulls SDA line high */
jamesadevine 0:e1a608bb55e8 54 #define TWI_SDA_LOW() do { NRF_GPIO->OUTCLR = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER); } while(0) /*!< Pulls SDA line low */
jamesadevine 0:e1a608bb55e8 55 #define TWI_SDA_INPUT() do { NRF_GPIO->DIRCLR = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER); } while(0) /*!< Configures SDA pin as input */
jamesadevine 0:e1a608bb55e8 56 #define TWI_SDA_OUTPUT() do { NRF_GPIO->DIRSET = (1UL << TWI_MASTER_CONFIG_DATA_PIN_NUMBER); } while(0) /*!< Configures SDA pin as output */
jamesadevine 0:e1a608bb55e8 57 #define TWI_SCL_OUTPUT() do { NRF_GPIO->DIRSET = (1UL << TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER); } while(0) /*!< Configures SCL pin as output */
jamesadevine 0:e1a608bb55e8 58 /*lint -restore */
jamesadevine 0:e1a608bb55e8 59
jamesadevine 0:e1a608bb55e8 60 #define TWI_SDA_READ() ((NRF_GPIO->IN >> TWI_MASTER_CONFIG_DATA_PIN_NUMBER) & 0x1UL) /*!< Reads current state of SDA */
jamesadevine 0:e1a608bb55e8 61 #define TWI_SCL_READ() ((NRF_GPIO->IN >> TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER) & 0x1UL) /*!< Reads current state of SCL */
jamesadevine 0:e1a608bb55e8 62
jamesadevine 0:e1a608bb55e8 63 #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. */
jamesadevine 0:e1a608bb55e8 64
jamesadevine 0:e1a608bb55e8 65
jamesadevine 0:e1a608bb55e8 66 /**
jamesadevine 0:e1a608bb55e8 67 * @brief Function for initializing TWI bus IO pins and checks if the bus is operational.
jamesadevine 0:e1a608bb55e8 68 *
jamesadevine 0:e1a608bb55e8 69 * Both pins are configured as Standard-0, No-drive-1 (open drain).
jamesadevine 0:e1a608bb55e8 70 *
jamesadevine 0:e1a608bb55e8 71 * @return
jamesadevine 0:e1a608bb55e8 72 * @retval true TWI bus is clear for transfers.
jamesadevine 0:e1a608bb55e8 73 * @retval false TWI bus is stuck.
jamesadevine 0:e1a608bb55e8 74 */
jamesadevine 0:e1a608bb55e8 75 bool twi_master_init_and_clear(void);
jamesadevine 0:e1a608bb55e8 76
jamesadevine 0:e1a608bb55e8 77 /**
jamesadevine 0:e1a608bb55e8 78 * @brief Function for transferring data over TWI bus.
jamesadevine 0:e1a608bb55e8 79 *
jamesadevine 0:e1a608bb55e8 80 * If TWI master detects even one NACK from the slave or timeout occurs, STOP condition is issued
jamesadevine 0:e1a608bb55e8 81 * and the function returns false.
jamesadevine 0:e1a608bb55e8 82 * Bit 0 (@ref TWI_READ_BIT) in the address parameter controls transfer direction;
jamesadevine 0:e1a608bb55e8 83 * - If 1, master reads data_length number of bytes from the slave
jamesadevine 0:e1a608bb55e8 84 * - If 0, master writes data_length number of bytes to the slave.
jamesadevine 0:e1a608bb55e8 85 *
jamesadevine 0:e1a608bb55e8 86 * @note Make sure at least data_length number of bytes is allocated in data if TWI_READ_BIT is set.
jamesadevine 0:e1a608bb55e8 87 * @note @ref TWI_ISSUE_STOP
jamesadevine 0:e1a608bb55e8 88 *
jamesadevine 0:e1a608bb55e8 89 * @param address Data transfer direction (LSB) / Slave address (7 MSBs).
jamesadevine 0:e1a608bb55e8 90 * @param data Pointer to data.
jamesadevine 0:e1a608bb55e8 91 * @param data_length Number of bytes to transfer.
jamesadevine 0:e1a608bb55e8 92 * @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.
jamesadevine 0:e1a608bb55e8 93 * @return
jamesadevine 0:e1a608bb55e8 94 * @retval true Data transfer succeeded without errors.
jamesadevine 0:e1a608bb55e8 95 * @retval false Data transfer failed.
jamesadevine 0:e1a608bb55e8 96 */
jamesadevine 0:e1a608bb55e8 97 bool twi_master_transfer(uint8_t address, uint8_t *data, uint8_t data_length, bool issue_stop_condition);
jamesadevine 0:e1a608bb55e8 98
jamesadevine 0:e1a608bb55e8 99 /**
jamesadevine 0:e1a608bb55e8 100 *@}
jamesadevine 0:e1a608bb55e8 101 **/
jamesadevine 0:e1a608bb55e8 102
jamesadevine 0:e1a608bb55e8 103 #ifdef __cplusplus
jamesadevine 0:e1a608bb55e8 104 }
jamesadevine 0:e1a608bb55e8 105 #endif
jamesadevine 0:e1a608bb55e8 106
jamesadevine 0:e1a608bb55e8 107 /*lint --flb "Leave library region" */
jamesadevine 0:e1a608bb55e8 108 #endif //TWI_MASTER_H