Yihui Xiong
/
Seeed_nRF51822_Motion
initial
Diff: mbed-src/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/twi_master.c
- Revision:
- 1:9d3b497333c0
- Parent:
- 0:638edba3adf6
--- a/mbed-src/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/twi_master.c Mon Jan 11 02:32:24 2016 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,304 +0,0 @@ -/* 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. - * - */ - -#include "twi_master.h" -#include "twi_config.h" -#include <stdbool.h> -#include <stdint.h> -#include "nrf.h" -#include "nrf_delay.h" - -/* Max cycles approximately to wait on RXDREADY and TXDREADY event, - * This is optimized way instead of using timers, this is not power aware. */ -#define MAX_TIMEOUT_LOOPS (20000UL) /**< MAX while loops to wait for RXD/TXD event */ - -static bool twi_master_write(uint8_t * data, uint8_t data_length, bool issue_stop_condition, NRF_TWI_Type* twi) -{ - uint32_t timeout = MAX_TIMEOUT_LOOPS; /* max loops to wait for EVENTS_TXDSENT event*/ - - if (data_length == 0) - { - /* Return false for requesting data of size 0 */ - return false; - } - - twi->TXD = *data++; - twi->TASKS_STARTTX = 1; - - /** @snippet [TWI HW master write] */ - while (true) - { - while (twi->EVENTS_TXDSENT == 0 && twi->EVENTS_ERROR == 0 && (--timeout)) - { - // Do nothing. - } - - if (timeout == 0 || NRF_TWI1->EVENTS_ERROR != 0) - { - // Recover the peripheral as indicated by PAN 56: "TWI: TWI module lock-up." found at - // Product Anomaly Notification document found at - // https://www.nordicsemi.com/eng/Products/Bluetooth-R-low-energy/nRF51822/#Downloads - twi->EVENTS_ERROR = 0; - twi->ENABLE = TWI_ENABLE_ENABLE_Disabled << TWI_ENABLE_ENABLE_Pos; - twi->POWER = 0; - nrf_delay_us(5); - twi->POWER = 1; - twi->ENABLE = TWI_ENABLE_ENABLE_Enabled << TWI_ENABLE_ENABLE_Pos; - - (void)twi_master_init_and_clear(twi); - - return false; - } - twi->EVENTS_TXDSENT = 0; - if (--data_length == 0) - { - break; - } - - twi->TXD = *data++; - } - /** @snippet [TWI HW master write] */ - - if (issue_stop_condition) - { - twi->EVENTS_STOPPED = 0; - twi->TASKS_STOP = 1; - /* Wait until stop sequence is sent */ - while(twi->EVENTS_STOPPED == 0) - { - // Do nothing. - } - } - return true; -} - - -/** @brief Function for read by twi_master. - */ -static bool twi_master_read(uint8_t * data, uint8_t data_length, bool issue_stop_condition, NRF_TWI_Type* twi) -{ - uint32_t timeout = MAX_TIMEOUT_LOOPS; /* max loops to wait for RXDREADY event*/ - - if (data_length == 0) - { - /* Return false for requesting data of size 0 */ - return false; - } - else if (data_length == 1) - { - NRF_PPI->CH[0].TEP = (uint32_t)&twi->TASKS_STOP; - } - else - { - NRF_PPI->CH[0].TEP = (uint32_t)&twi->TASKS_SUSPEND; - } - - NRF_PPI->CHENSET = PPI_CHENSET_CH0_Msk; - twi->EVENTS_RXDREADY = 0; - twi->TASKS_STARTRX = 1; - - /** @snippet [TWI HW master read] */ - while (true) - { - while (twi->EVENTS_RXDREADY == 0 && NRF_TWI1->EVENTS_ERROR == 0 && (--timeout)) - { - // Do nothing. - } - twi->EVENTS_RXDREADY = 0; - - if (timeout == 0 || twi->EVENTS_ERROR != 0) - { - // Recover the peripheral as indicated by PAN 56: "TWI: TWI module lock-up." found at - // Product Anomaly Notification document found at - // https://www.nordicsemi.com/eng/Products/Bluetooth-R-low-energy/nRF51822/#Downloads - twi->EVENTS_ERROR = 0; - twi->ENABLE = TWI_ENABLE_ENABLE_Disabled << TWI_ENABLE_ENABLE_Pos; - twi->POWER = 0; - nrf_delay_us(5); - twi->POWER = 1; - twi->ENABLE = TWI_ENABLE_ENABLE_Enabled << TWI_ENABLE_ENABLE_Pos; - - (void)twi_master_init_and_clear(twi); - - return false; - } - - *data++ = NRF_TWI1->RXD; - - /* Configure PPI to stop TWI master before we get last BB event */ - if (--data_length == 1) - { - NRF_PPI->CH[0].TEP = (uint32_t)&NRF_TWI1->TASKS_STOP; - } - - if (data_length == 0) - { - break; - } - - // Recover the peripheral as indicated by PAN 56: "TWI: TWI module lock-up." found at - // Product Anomaly Notification document found at - // https://www.nordicsemi.com/eng/Products/Bluetooth-R-low-energy/nRF51822/#Downloads - nrf_delay_us(20); - twi->TASKS_RESUME = 1; - } - /** @snippet [TWI HW master read] */ - - /* Wait until stop sequence is sent */ - while(twi->EVENTS_STOPPED == 0) - { - // Do nothing. - } - twi->EVENTS_STOPPED = 0; - - NRF_PPI->CHENCLR = PPI_CHENCLR_CH0_Msk; - return true; -} - - -/** - * @brief Function for detecting stuck slaves (SDA = 0 and SCL = 1) and tries to clear the bus. - * - * @return - * @retval false Bus is stuck. - * @retval true Bus is clear. - */ -static bool twi_master_clear_bus(NRF_TWI_Type* twi) -{ - uint32_t twi_state; - bool bus_clear; - uint32_t clk_pin_config; - uint32_t data_pin_config; - - // Save and disable TWI hardware so software can take control over the pins. - twi_state = twi->ENABLE; - twi->ENABLE = TWI_ENABLE_ENABLE_Disabled << TWI_ENABLE_ENABLE_Pos; - - clk_pin_config = \ - NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER]; - NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER] = \ - (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos) \ - | (GPIO_PIN_CNF_DRIVE_S0D1 << GPIO_PIN_CNF_DRIVE_Pos) \ - | (GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos) \ - | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) \ - | (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos); - - data_pin_config = \ - NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_DATA_PIN_NUMBER]; - NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_DATA_PIN_NUMBER] = \ - (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos) \ - | (GPIO_PIN_CNF_DRIVE_S0D1 << GPIO_PIN_CNF_DRIVE_Pos) \ - | (GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos) \ - | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) \ - | (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos); - - TWI_SDA_HIGH(); - TWI_SCL_HIGH(); - TWI_DELAY(); - - if ((TWI_SDA_READ() == 1) && (TWI_SCL_READ() == 1)) - { - bus_clear = true; - } - else - { - uint_fast8_t i; - bus_clear = false; - - // Clock max 18 pulses worst case scenario(9 for master to send the rest of command and 9 - // for slave to respond) to SCL line and wait for SDA come high. - for (i=18; i--;) - { - TWI_SCL_LOW(); - TWI_DELAY(); - TWI_SCL_HIGH(); - TWI_DELAY(); - - if (TWI_SDA_READ() == 1) - { - bus_clear = true; - break; - } - } - } - - NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER] = clk_pin_config; - NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_DATA_PIN_NUMBER] = data_pin_config; - - twi->ENABLE = twi_state; - - return bus_clear; -} - - -/** @brief Function for initializing the twi_master. - */ -bool twi_master_init_and_clear(NRF_TWI_Type* twi) -{ - /* To secure correct signal levels on the pins used by the TWI - master when the system is in OFF mode, and when the TWI master is - disabled, these pins must be configured in the GPIO peripheral. - */ - NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER] = \ - (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos) \ - | (GPIO_PIN_CNF_DRIVE_S0D1 << GPIO_PIN_CNF_DRIVE_Pos) \ - | (GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos) \ - | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) \ - | (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos); - - NRF_GPIO->PIN_CNF[TWI_MASTER_CONFIG_DATA_PIN_NUMBER] = \ - (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos) \ - | (GPIO_PIN_CNF_DRIVE_S0D1 << GPIO_PIN_CNF_DRIVE_Pos) \ - | (GPIO_PIN_CNF_PULL_Pullup << GPIO_PIN_CNF_PULL_Pos) \ - | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) \ - | (GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos); - - twi->EVENTS_RXDREADY = 0; - twi->EVENTS_TXDSENT = 0; - twi->PSELSCL = TWI_MASTER_CONFIG_CLOCK_PIN_NUMBER; - twi->PSELSDA = TWI_MASTER_CONFIG_DATA_PIN_NUMBER; - twi->FREQUENCY = TWI_FREQUENCY_FREQUENCY_K100 << TWI_FREQUENCY_FREQUENCY_Pos; - NRF_PPI->CH[0].EEP = (uint32_t)&twi->EVENTS_BB; - NRF_PPI->CH[0].TEP = (uint32_t)&twi->TASKS_SUSPEND; - NRF_PPI->CHENCLR = PPI_CHENCLR_CH0_Msk; - twi->ENABLE = TWI_ENABLE_ENABLE_Enabled << TWI_ENABLE_ENABLE_Pos; - - return twi_master_clear_bus(twi); -} - - -/** @brief Function for transfer by twi_master. - */ -bool twi_master_transfer(uint8_t address, - uint8_t * data, - uint8_t data_length, - bool issue_stop_condition, - NRF_TWI_Type* twi) -{ - bool transfer_succeeded = false; - if (data_length > 0 && twi_master_clear_bus(twi)) - { - twi->ADDRESS = (address >> 1); - - if ((address & TWI_READ_BIT)) - { - transfer_succeeded = twi_master_read(data, data_length, issue_stop_condition, twi); - } - else - { - transfer_succeeded = twi_master_write(data, data_length, issue_stop_condition, twi); - } - } - return transfer_succeeded; -} - -/*lint --flb "Leave library region" */