fixed drive strength
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targets/TARGET_NORDIC/TARGET_MCU_NRF51822/i2c_api.c
- Committer:
- cpadua
- Date:
- 2017-04-11
- Revision:
- 163:1d4c9d0af1e9
- Parent:
- 149:156823d33999
File content as of revision 163:1d4c9d0af1e9:
/* mbed Microcontroller Library * Copyright (c) 2013 Nordic Semiconductor * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "mbed_assert.h" #include "i2c_api.h" #include "cmsis.h" #include "pinmap.h" #include "twi_master.h" #include "mbed_error.h" // nRF51822's I2C_0 and SPI_0 (I2C_1, SPI_1 and SPIS1) share the same address. // They can't be used at the same time. So we use two global variable to track the usage. // See nRF51822 address information at nRF51822_PS v2.0.pdf - Table 15 Peripheral instance reference volatile i2c_spi_peripheral_t i2c0_spi0_peripheral = {0, 0, 0, 0}; volatile i2c_spi_peripheral_t i2c1_spi1_peripheral = {0, 0, 0, 0}; void i2c_interface_enable(i2c_t *obj) { obj->i2c->ENABLE = (TWI_ENABLE_ENABLE_Enabled << TWI_ENABLE_ENABLE_Pos); } void twi_master_init(i2c_t *obj, PinName sda, PinName scl, int frequency) { NRF_GPIO->PIN_CNF[scl] = ((GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos) | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) | (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos) | (GPIO_PIN_CNF_DRIVE_H0D1 << GPIO_PIN_CNF_DRIVE_Pos) | (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)); NRF_GPIO->PIN_CNF[sda] = ((GPIO_PIN_CNF_DIR_Input << GPIO_PIN_CNF_DIR_Pos) | (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) | (GPIO_PIN_CNF_PULL_Disabled << GPIO_PIN_CNF_PULL_Pos) | (GPIO_PIN_CNF_DRIVE_H0D1 << GPIO_PIN_CNF_DRIVE_Pos) | (GPIO_PIN_CNF_SENSE_Disabled << GPIO_PIN_CNF_SENSE_Pos)); obj->i2c->PSELSCL = scl; obj->i2c->PSELSDA = sda; // set default frequency at 100k i2c_frequency(obj, frequency); i2c_interface_enable(obj); } void i2c_init(i2c_t *obj, PinName sda, PinName scl) { NRF_TWI_Type *i2c = NULL; if (i2c0_spi0_peripheral.usage == I2C_SPI_PERIPHERAL_FOR_I2C && i2c0_spi0_peripheral.sda_mosi == (uint8_t)sda && i2c0_spi0_peripheral.scl_miso == (uint8_t)scl) { // The I2C with the same pins is already initialized i2c = (NRF_TWI_Type *)I2C_0; obj->peripheral = 0x1; } else if (i2c1_spi1_peripheral.usage == I2C_SPI_PERIPHERAL_FOR_I2C && i2c1_spi1_peripheral.sda_mosi == (uint8_t)sda && i2c1_spi1_peripheral.scl_miso == (uint8_t)scl) { // The I2C with the same pins is already initialized i2c = (NRF_TWI_Type *)I2C_1; obj->peripheral = 0x2; } else if (i2c0_spi0_peripheral.usage == 0) { i2c0_spi0_peripheral.usage = I2C_SPI_PERIPHERAL_FOR_I2C; i2c0_spi0_peripheral.sda_mosi = (uint8_t)sda; i2c0_spi0_peripheral.scl_miso = (uint8_t)scl; i2c = (NRF_TWI_Type *)I2C_0; obj->peripheral = 0x1; } else if (i2c1_spi1_peripheral.usage == 0) { i2c1_spi1_peripheral.usage = I2C_SPI_PERIPHERAL_FOR_I2C; i2c1_spi1_peripheral.sda_mosi = (uint8_t)sda; i2c1_spi1_peripheral.scl_miso = (uint8_t)scl; i2c = (NRF_TWI_Type *)I2C_1; obj->peripheral = 0x2; } else { // No available peripheral error("No available I2C"); } twi_master_init_and_clear(i2c); obj->i2c = i2c; obj->scl = scl; obj->sda = sda; obj->i2c->EVENTS_ERROR = 0; obj->i2c->ENABLE = TWI_ENABLE_ENABLE_Disabled << TWI_ENABLE_ENABLE_Pos; obj->i2c->POWER = 0; for (int i = 0; i<100; i++) { } obj->i2c->POWER = 1; twi_master_init(obj, sda, scl, 100000); } void i2c_reset(i2c_t *obj) { obj->i2c->EVENTS_ERROR = 0; obj->i2c->ENABLE = TWI_ENABLE_ENABLE_Disabled << TWI_ENABLE_ENABLE_Pos; obj->i2c->POWER = 0; for (int i = 0; i<100; i++) { } obj->i2c->POWER = 1; twi_master_init(obj, obj->sda, obj->scl, obj->freq); } int i2c_start(i2c_t *obj) { int status = 0; i2c_reset(obj); obj->address_set = 0; return status; } int i2c_stop(i2c_t *obj) { int timeOut = 100000; obj->i2c->EVENTS_STOPPED = 0; // write the stop bit obj->i2c->TASKS_STOP = 1; while (!obj->i2c->EVENTS_STOPPED) { timeOut--; if (timeOut<0) { return 1; } } obj->address_set = 0; i2c_reset(obj); return 0; } int i2c_do_write(i2c_t *obj, int value) { int timeOut = 100000; obj->i2c->TXD = value; while (!obj->i2c->EVENTS_TXDSENT) { timeOut--; if (timeOut<0) { return 1; } } obj->i2c->EVENTS_TXDSENT = 0; return 0; } int i2c_do_read(i2c_t *obj, char *data, int last) { int timeOut = 100000; if (last) { // To trigger stop task when a byte is received, // must be set before resume task. obj->i2c->SHORTS = 2; } obj->i2c->TASKS_RESUME = 1; while (!obj->i2c->EVENTS_RXDREADY) { timeOut--; if (timeOut<0) { return 1; } } obj->i2c->EVENTS_RXDREADY = 0; *data = obj->i2c->RXD; return 0; } void i2c_frequency(i2c_t *obj, int hz) { if (hz<250000) { obj->freq = 100000; obj->i2c->FREQUENCY = (TWI_FREQUENCY_FREQUENCY_K100 << TWI_FREQUENCY_FREQUENCY_Pos); } else if (hz<400000) { obj->freq = 250000; obj->i2c->FREQUENCY = (TWI_FREQUENCY_FREQUENCY_K250 << TWI_FREQUENCY_FREQUENCY_Pos); } else { obj->freq = 400000; obj->i2c->FREQUENCY = (TWI_FREQUENCY_FREQUENCY_K400 << TWI_FREQUENCY_FREQUENCY_Pos); } } int checkError(i2c_t *obj) { if (obj->i2c->EVENTS_ERROR == 1) { if (obj->i2c->ERRORSRC & TWI_ERRORSRC_ANACK_Msk) { obj->i2c->EVENTS_ERROR = 0; obj->i2c->TASKS_STOP = 1; return I2C_ERROR_BUS_BUSY; } obj->i2c->EVENTS_ERROR = 0; obj->i2c->TASKS_STOP = 1; return I2C_ERROR_NO_SLAVE; } return 0; } int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) { int status, count, errorResult; obj->i2c->ADDRESS = (address >> 1); obj->i2c->SHORTS = 1; // to trigger suspend task when a byte is received obj->i2c->EVENTS_RXDREADY = 0; obj->i2c->TASKS_STARTRX = 1; // Read in all except last byte for (count = 0; count < (length - 1); count++) { status = i2c_do_read(obj, &data[count], 0); if (status) { errorResult = checkError(obj); i2c_reset(obj); if (errorResult<0) { return errorResult; } return count; } } // read in last byte status = i2c_do_read(obj, &data[length - 1], 1); if (status) { i2c_reset(obj); return length - 1; } // If not repeated start, send stop. if (stop) { while (!obj->i2c->EVENTS_STOPPED) { } obj->i2c->EVENTS_STOPPED = 0; } return length; } int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) { int status, errorResult; obj->i2c->ADDRESS = (address >> 1); obj->i2c->SHORTS = 0; obj->i2c->TASKS_STARTTX = 1; for (int i = 0; i<length; i++) { status = i2c_do_write(obj, data[i]); if (status) { i2c_reset(obj); errorResult = checkError(obj); if (errorResult<0) { return errorResult; } return i; } } // If not repeated start, send stop. if (stop) { if (i2c_stop(obj)) { return I2C_ERROR_NO_SLAVE; } } return length; } int i2c_byte_read(i2c_t *obj, int last) { char data; int status; status = i2c_do_read(obj, &data, last); if (status) { i2c_reset(obj); } return data; } int i2c_byte_write(i2c_t *obj, int data) { int status = 0; if (!obj->address_set) { obj->address_set = 1; obj->i2c->ADDRESS = (data >> 1); if (data & 1) { obj->i2c->EVENTS_RXDREADY = 0; obj->i2c->SHORTS = 1; obj->i2c->TASKS_STARTRX = 1; } else { obj->i2c->SHORTS = 0; obj->i2c->TASKS_STARTTX = 1; } } else { status = i2c_do_write(obj, data); if (status) { i2c_reset(obj); } } return (1 - status); }