mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
Diff: targets/hal/TARGET_NORDIC/TARGET_NRF51822/i2c_api.c
- Revision:
- 85:e1a8e879a6a9
- Child:
- 104:a6a92e2e5a92
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_NORDIC/TARGET_NRF51822/i2c_api.c Fri Feb 07 18:00:11 2014 +0000 @@ -0,0 +1,276 @@ +/* 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); +}