mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
targets/hal/TARGET_NORDIC/TARGET_NRF51822/i2c_api.c
- Committer:
- mbed_official
- Date:
- 2014-02-07
- Revision:
- 85:e1a8e879a6a9
- Child:
- 104:a6a92e2e5a92
File content as of revision 85:e1a8e879a6a9:
/* mbed Microcontroller Library * Copyright (c) 2006-2013 ARM Limited * * 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 "i2c_api.h" #include "cmsis.h" #include "pinmap.h" #include "error.h" static const PinMap PinMap_I2C_SDA[] = { {p22, I2C_0, 1}, {p13, I2C_1, 2}, {NC , NC , 0} }; static const PinMap PinMap_I2C_SCL[] = { {p20, I2C_0, 1}, {p15, I2C_1, 2}, {NC , NC, 0} }; uint8_t addrSet=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_S0D1 << 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_S0D1 << 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) { // determine the SPI to use I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA); I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL); I2CName i2c = (I2CName)pinmap_merge(i2c_sda,i2c_scl); obj->i2c = (NRF_TWI_Type *)i2c; if ((int)obj->i2c == NC) { error("I2C pin mapping failed"); } 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); addrSet=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; } addrSet = 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; while(!obj->i2c->EVENTS_RXDREADY){ timeOut--; if(timeOut<0) return 1; } obj->i2c->EVENTS_RXDREADY = 0; if (last){ obj->i2c->TASKS_STOP = 1; } *data = obj->i2c->RXD; for(int i=0;i<320;i++){ } obj->i2c->TASKS_RESUME = 1; 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 = 0; 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(!addrSet){ addrSet = 1; obj->i2c->ADDRESS = (data>>1); if(data&1){ obj->i2c->EVENTS_RXDREADY = 0; obj->i2c->TASKS_STARTRX = 1; } else{ obj->i2c->TASKS_STARTTX = 1; } } else{ status = i2c_do_write(obj, data); if(status) { i2c_reset(obj); } } return (1-status); }