Diff: targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/i2c_api.c

Revision:

270:e2babe29baf8

Parent:

227:7bd0639b8911

Child:

300:55638feb26a4

diff -r 0e58554f11d5 -r e2babe29baf8 targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/i2c_api.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/hal/TARGET_NORDIC/TARGET_MCU_NRF51822/i2c_api.c	Fri Aug 01 14:45:06 2014 +0100
@@ -0,0 +1,273 @@
+/* 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"
+
+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;
+    
+    MBED_ASSERT((int)obj->i2c != NC);
+
+    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;
+
+    if (last){
+        obj->i2c->TASKS_STOP = 1;
+    }
+    while(!obj->i2c->EVENTS_RXDREADY){
+        timeOut--;
+        if(timeOut<0)
+            return 1;
+    }
+    obj->i2c->EVENTS_RXDREADY       = 0;
+    
+    *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);
+}