EL4121 Embedded System / mbed-os

mbed-os

Dependents:   cobaLCDJoyMotor_Thread odometry_omni_3roda_v3 odometry_omni_3roda_v1 odometry_omni_3roda_v2 ... more

targets/TARGET_NXP/TARGET_LPC15XX/i2c_api.c@0:b74591d5ab33, 2017-12-11 (annotated)

Committer:
be_bryan
Date:
Mon Dec 11 17:54:04 2017 +0000
Revision:
0:b74591d5ab33
motor ++

Who changed what in which revision?

UserRevisionLine numberNew contents of line
be_bryan 0:b74591d5ab33 1 /* mbed Microcontroller Library
be_bryan 0:b74591d5ab33 2 * Copyright (c) 2006-2013 ARM Limited
be_bryan 0:b74591d5ab33 3 *
be_bryan 0:b74591d5ab33 4 * Licensed under the Apache License, Version 2.0 (the "License");
be_bryan 0:b74591d5ab33 5 * you may not use this file except in compliance with the License.
be_bryan 0:b74591d5ab33 6 * You may obtain a copy of the License at
be_bryan 0:b74591d5ab33 7 *
be_bryan 0:b74591d5ab33 8 * http://www.apache.org/licenses/LICENSE-2.0
be_bryan 0:b74591d5ab33 9 *
be_bryan 0:b74591d5ab33 10 * Unless required by applicable law or agreed to in writing, software
be_bryan 0:b74591d5ab33 11 * distributed under the License is distributed on an "AS IS" BASIS,
be_bryan 0:b74591d5ab33 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
be_bryan 0:b74591d5ab33 13 * See the License for the specific language governing permissions and
be_bryan 0:b74591d5ab33 14 * limitations under the License.
be_bryan 0:b74591d5ab33 15 */
be_bryan 0:b74591d5ab33 16 #include "mbed_assert.h"
be_bryan 0:b74591d5ab33 17 #include "i2c_api.h"
be_bryan 0:b74591d5ab33 18 #include "cmsis.h"
be_bryan 0:b74591d5ab33 19 #include "pinmap.h"
be_bryan 0:b74591d5ab33 20
be_bryan 0:b74591d5ab33 21 static uint8_t repeated_start = 0;
be_bryan 0:b74591d5ab33 22
be_bryan 0:b74591d5ab33 23 #define I2C_STAT(x) ((LPC_I2C0->STAT >> 1) & (0x07))
be_bryan 0:b74591d5ab33 24
be_bryan 0:b74591d5ab33 25 static inline int i2c_status(i2c_t *obj) {
be_bryan 0:b74591d5ab33 26 return I2C_STAT(obj);
be_bryan 0:b74591d5ab33 27 }
be_bryan 0:b74591d5ab33 28
be_bryan 0:b74591d5ab33 29 // Wait until the Serial Interrupt (SI) is set
be_bryan 0:b74591d5ab33 30 static int i2c_wait_SI(i2c_t *obj) {
be_bryan 0:b74591d5ab33 31 volatile int timeout = 0;
be_bryan 0:b74591d5ab33 32 while (!(LPC_I2C0->STAT & (1 << 0))) {
be_bryan 0:b74591d5ab33 33 timeout++;
be_bryan 0:b74591d5ab33 34 if (timeout > 100000) return -1;
be_bryan 0:b74591d5ab33 35 }
be_bryan 0:b74591d5ab33 36 return 0;
be_bryan 0:b74591d5ab33 37 }
be_bryan 0:b74591d5ab33 38
be_bryan 0:b74591d5ab33 39 static inline void i2c_interface_enable(i2c_t *obj) {
be_bryan 0:b74591d5ab33 40 LPC_I2C0->CFG |= (1 << 0);
be_bryan 0:b74591d5ab33 41 }
be_bryan 0:b74591d5ab33 42
be_bryan 0:b74591d5ab33 43 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
be_bryan 0:b74591d5ab33 44 MBED_ASSERT((sda == P0_23) && (scl == P0_22));
be_bryan 0:b74591d5ab33 45
be_bryan 0:b74591d5ab33 46 // Enables clock for I2C0
be_bryan 0:b74591d5ab33 47 LPC_SYSCON->SYSAHBCLKCTRL1 |= (1 << 13);
be_bryan 0:b74591d5ab33 48
be_bryan 0:b74591d5ab33 49 LPC_SYSCON->PRESETCTRL1 |= (1 << 13);
be_bryan 0:b74591d5ab33 50 LPC_SYSCON->PRESETCTRL1 &= ~(1 << 13);
be_bryan 0:b74591d5ab33 51
be_bryan 0:b74591d5ab33 52 // pin enable
be_bryan 0:b74591d5ab33 53 LPC_SWM->PINENABLE1 &= ~(0x3 << 3);
be_bryan 0:b74591d5ab33 54
be_bryan 0:b74591d5ab33 55 // set default frequency at 100kHz
be_bryan 0:b74591d5ab33 56 i2c_frequency(obj, 100000);
be_bryan 0:b74591d5ab33 57 i2c_interface_enable(obj);
be_bryan 0:b74591d5ab33 58 }
be_bryan 0:b74591d5ab33 59
be_bryan 0:b74591d5ab33 60 inline int i2c_start(i2c_t *obj) {
be_bryan 0:b74591d5ab33 61 int status = 0;
be_bryan 0:b74591d5ab33 62 if (repeated_start) {
be_bryan 0:b74591d5ab33 63 LPC_I2C0->MSTCTL = (1 << 1) | (1 << 0);
be_bryan 0:b74591d5ab33 64 repeated_start = 0;
be_bryan 0:b74591d5ab33 65 } else {
be_bryan 0:b74591d5ab33 66 LPC_I2C0->MSTCTL = (1 << 1);
be_bryan 0:b74591d5ab33 67 }
be_bryan 0:b74591d5ab33 68 return status;
be_bryan 0:b74591d5ab33 69 }
be_bryan 0:b74591d5ab33 70
be_bryan 0:b74591d5ab33 71 inline int i2c_stop(i2c_t *obj) {
be_bryan 0:b74591d5ab33 72 volatile int timeout = 0;
be_bryan 0:b74591d5ab33 73
be_bryan 0:b74591d5ab33 74 LPC_I2C0->MSTCTL = (1 << 2) | (1 << 0);
be_bryan 0:b74591d5ab33 75 while ((LPC_I2C0->STAT & ((1 << 0) | (7 << 1))) != ((1 << 0) | (0 << 1))) {
be_bryan 0:b74591d5ab33 76 timeout ++;
be_bryan 0:b74591d5ab33 77 if (timeout > 100000) return 1;
be_bryan 0:b74591d5ab33 78 }
be_bryan 0:b74591d5ab33 79
be_bryan 0:b74591d5ab33 80 return 0;
be_bryan 0:b74591d5ab33 81 }
be_bryan 0:b74591d5ab33 82
be_bryan 0:b74591d5ab33 83
be_bryan 0:b74591d5ab33 84 static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) {
be_bryan 0:b74591d5ab33 85 // write the data
be_bryan 0:b74591d5ab33 86 LPC_I2C0->MSTDAT = value;
be_bryan 0:b74591d5ab33 87
be_bryan 0:b74591d5ab33 88 if (!addr)
be_bryan 0:b74591d5ab33 89 LPC_I2C0->MSTCTL = (1 << 0);
be_bryan 0:b74591d5ab33 90
be_bryan 0:b74591d5ab33 91 // wait and return status
be_bryan 0:b74591d5ab33 92 i2c_wait_SI(obj);
be_bryan 0:b74591d5ab33 93 return i2c_status(obj);
be_bryan 0:b74591d5ab33 94 }
be_bryan 0:b74591d5ab33 95
be_bryan 0:b74591d5ab33 96 static inline int i2c_do_read(i2c_t *obj, int last) {
be_bryan 0:b74591d5ab33 97 // wait for it to arrive
be_bryan 0:b74591d5ab33 98 i2c_wait_SI(obj);
be_bryan 0:b74591d5ab33 99 if (!last)
be_bryan 0:b74591d5ab33 100 LPC_I2C0->MSTCTL = (1 << 0);
be_bryan 0:b74591d5ab33 101
be_bryan 0:b74591d5ab33 102 // return the data
be_bryan 0:b74591d5ab33 103 return (LPC_I2C0->MSTDAT & 0xFF);
be_bryan 0:b74591d5ab33 104 }
be_bryan 0:b74591d5ab33 105
be_bryan 0:b74591d5ab33 106 void i2c_frequency(i2c_t *obj, int hz) {
be_bryan 0:b74591d5ab33 107 // No peripheral clock divider on the M0
be_bryan 0:b74591d5ab33 108 uint32_t PCLK = SystemCoreClock;
be_bryan 0:b74591d5ab33 109 uint32_t clkdiv = PCLK / (hz * 4) - 1;
be_bryan 0:b74591d5ab33 110
be_bryan 0:b74591d5ab33 111 LPC_I2C0->DIV = clkdiv;
be_bryan 0:b74591d5ab33 112 LPC_I2C0->MSTTIME = 0;
be_bryan 0:b74591d5ab33 113 }
be_bryan 0:b74591d5ab33 114
be_bryan 0:b74591d5ab33 115 int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
be_bryan 0:b74591d5ab33 116 int count, status;
be_bryan 0:b74591d5ab33 117
be_bryan 0:b74591d5ab33 118 i2c_start(obj);
be_bryan 0:b74591d5ab33 119
be_bryan 0:b74591d5ab33 120 LPC_I2C0->MSTDAT = (address | 0x01);
be_bryan 0:b74591d5ab33 121 LPC_I2C0->MSTCTL |= 0x20;
be_bryan 0:b74591d5ab33 122 if (i2c_wait_SI(obj) == -1)
be_bryan 0:b74591d5ab33 123 return -1;
be_bryan 0:b74591d5ab33 124
be_bryan 0:b74591d5ab33 125 status = ((LPC_I2C0->STAT >> 1) & (0x07));
be_bryan 0:b74591d5ab33 126 if (status != 0x01) {
be_bryan 0:b74591d5ab33 127 i2c_stop(obj);
be_bryan 0:b74591d5ab33 128 return I2C_ERROR_NO_SLAVE;
be_bryan 0:b74591d5ab33 129 }
be_bryan 0:b74591d5ab33 130
be_bryan 0:b74591d5ab33 131 // Read in all except last byte
be_bryan 0:b74591d5ab33 132 for (count = 0; count < (length - 1); count++) {
be_bryan 0:b74591d5ab33 133 if (i2c_wait_SI(obj) == -1)
be_bryan 0:b74591d5ab33 134 return -1;
be_bryan 0:b74591d5ab33 135 LPC_I2C0->MSTCTL = (1 << 0);
be_bryan 0:b74591d5ab33 136 data[count] = (LPC_I2C0->MSTDAT & 0xFF);
be_bryan 0:b74591d5ab33 137 status = ((LPC_I2C0->STAT >> 1) & (0x07));
be_bryan 0:b74591d5ab33 138 if (status != 0x01) {
be_bryan 0:b74591d5ab33 139 i2c_stop(obj);
be_bryan 0:b74591d5ab33 140 return count;
be_bryan 0:b74591d5ab33 141 }
be_bryan 0:b74591d5ab33 142 }
be_bryan 0:b74591d5ab33 143
be_bryan 0:b74591d5ab33 144 // read in last byte
be_bryan 0:b74591d5ab33 145 if (i2c_wait_SI(obj) == -1)
be_bryan 0:b74591d5ab33 146 return -1;
be_bryan 0:b74591d5ab33 147
be_bryan 0:b74591d5ab33 148 data[count] = (LPC_I2C0->MSTDAT & 0xFF);
be_bryan 0:b74591d5ab33 149 status = i2c_status(obj);
be_bryan 0:b74591d5ab33 150 if (status != 0x01) {
be_bryan 0:b74591d5ab33 151 i2c_stop(obj);
be_bryan 0:b74591d5ab33 152 return length - 1;
be_bryan 0:b74591d5ab33 153 }
be_bryan 0:b74591d5ab33 154 // If not repeated start, send stop.
be_bryan 0:b74591d5ab33 155 if (stop) {
be_bryan 0:b74591d5ab33 156 i2c_stop(obj);
be_bryan 0:b74591d5ab33 157 } else {
be_bryan 0:b74591d5ab33 158 repeated_start = 1;
be_bryan 0:b74591d5ab33 159 }
be_bryan 0:b74591d5ab33 160
be_bryan 0:b74591d5ab33 161 return length;
be_bryan 0:b74591d5ab33 162 }
be_bryan 0:b74591d5ab33 163
be_bryan 0:b74591d5ab33 164 int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
be_bryan 0:b74591d5ab33 165 int i, status;
be_bryan 0:b74591d5ab33 166
be_bryan 0:b74591d5ab33 167 i2c_start(obj);
be_bryan 0:b74591d5ab33 168
be_bryan 0:b74591d5ab33 169 LPC_I2C0->MSTDAT = (address & 0xFE);
be_bryan 0:b74591d5ab33 170 LPC_I2C0->MSTCTL |= 0x20;
be_bryan 0:b74591d5ab33 171 if (i2c_wait_SI(obj) == -1)
be_bryan 0:b74591d5ab33 172 return -1;
be_bryan 0:b74591d5ab33 173
be_bryan 0:b74591d5ab33 174 status = ((LPC_I2C0->STAT >> 1) & (0x07));
be_bryan 0:b74591d5ab33 175 if (status != 0x02) {
be_bryan 0:b74591d5ab33 176 i2c_stop(obj);
be_bryan 0:b74591d5ab33 177 return I2C_ERROR_NO_SLAVE;
be_bryan 0:b74591d5ab33 178 }
be_bryan 0:b74591d5ab33 179
be_bryan 0:b74591d5ab33 180 for (i=0; i<length; i++) {
be_bryan 0:b74591d5ab33 181 LPC_I2C0->MSTDAT = data[i];
be_bryan 0:b74591d5ab33 182 LPC_I2C0->MSTCTL = (1 << 0);
be_bryan 0:b74591d5ab33 183 if (i2c_wait_SI(obj) == -1)
be_bryan 0:b74591d5ab33 184 return -1;
be_bryan 0:b74591d5ab33 185
be_bryan 0:b74591d5ab33 186 status = ((LPC_I2C0->STAT >> 1) & (0x07));
be_bryan 0:b74591d5ab33 187 if (status != 0x02) {
be_bryan 0:b74591d5ab33 188 i2c_stop(obj);
be_bryan 0:b74591d5ab33 189 return i;
be_bryan 0:b74591d5ab33 190 }
be_bryan 0:b74591d5ab33 191 }
be_bryan 0:b74591d5ab33 192
be_bryan 0:b74591d5ab33 193 // If not repeated start, send stop.
be_bryan 0:b74591d5ab33 194 if (stop) {
be_bryan 0:b74591d5ab33 195 i2c_stop(obj);
be_bryan 0:b74591d5ab33 196 } else {
be_bryan 0:b74591d5ab33 197 repeated_start = 1;
be_bryan 0:b74591d5ab33 198 }
be_bryan 0:b74591d5ab33 199
be_bryan 0:b74591d5ab33 200 return length;
be_bryan 0:b74591d5ab33 201 }
be_bryan 0:b74591d5ab33 202
be_bryan 0:b74591d5ab33 203 void i2c_reset(i2c_t *obj) {
be_bryan 0:b74591d5ab33 204 i2c_stop(obj);
be_bryan 0:b74591d5ab33 205 }
be_bryan 0:b74591d5ab33 206
be_bryan 0:b74591d5ab33 207 int i2c_byte_read(i2c_t *obj, int last) {
be_bryan 0:b74591d5ab33 208 return (i2c_do_read(obj, last) & 0xFF);
be_bryan 0:b74591d5ab33 209 }
be_bryan 0:b74591d5ab33 210
be_bryan 0:b74591d5ab33 211 int i2c_byte_write(i2c_t *obj, int data) {
be_bryan 0:b74591d5ab33 212 if (i2c_do_write(obj, (data & 0xFF), 0) == 2) {
be_bryan 0:b74591d5ab33 213 return 1;
be_bryan 0:b74591d5ab33 214 } else {
be_bryan 0:b74591d5ab33 215 return 0;
be_bryan 0:b74591d5ab33 216 }
be_bryan 0:b74591d5ab33 217 }