mbed library sources
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targets/hal/TARGET_NXP/TARGET_LPC81X/i2c_api.c@13:0645d8841f51, 2013-08-05 (annotated)
- Committer:
- bogdanm
- Date:
- Mon Aug 05 14:12:34 2013 +0300
- Revision:
- 13:0645d8841f51
Update mbed sources to revision 64
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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bogdanm | 13:0645d8841f51 | 1 | /* mbed Microcontroller Library |
bogdanm | 13:0645d8841f51 | 2 | * Copyright (c) 2006-2013 ARM Limited |
bogdanm | 13:0645d8841f51 | 3 | * |
bogdanm | 13:0645d8841f51 | 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
bogdanm | 13:0645d8841f51 | 5 | * you may not use this file except in compliance with the License. |
bogdanm | 13:0645d8841f51 | 6 | * You may obtain a copy of the License at |
bogdanm | 13:0645d8841f51 | 7 | * |
bogdanm | 13:0645d8841f51 | 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
bogdanm | 13:0645d8841f51 | 9 | * |
bogdanm | 13:0645d8841f51 | 10 | * Unless required by applicable law or agreed to in writing, software |
bogdanm | 13:0645d8841f51 | 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
bogdanm | 13:0645d8841f51 | 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
bogdanm | 13:0645d8841f51 | 13 | * See the License for the specific language governing permissions and |
bogdanm | 13:0645d8841f51 | 14 | * limitations under the License. |
bogdanm | 13:0645d8841f51 | 15 | */ |
bogdanm | 13:0645d8841f51 | 16 | #include "i2c_api.h" |
bogdanm | 13:0645d8841f51 | 17 | #include "cmsis.h" |
bogdanm | 13:0645d8841f51 | 18 | #include "pinmap.h" |
bogdanm | 13:0645d8841f51 | 19 | #include "error.h" |
bogdanm | 13:0645d8841f51 | 20 | |
bogdanm | 13:0645d8841f51 | 21 | static const SWM_Map SWM_I2C_SDA[] = { |
bogdanm | 13:0645d8841f51 | 22 | {7, 24}, |
bogdanm | 13:0645d8841f51 | 23 | }; |
bogdanm | 13:0645d8841f51 | 24 | |
bogdanm | 13:0645d8841f51 | 25 | static const SWM_Map SWM_I2C_SCL[] = { |
bogdanm | 13:0645d8841f51 | 26 | {8, 0}, |
bogdanm | 13:0645d8841f51 | 27 | }; |
bogdanm | 13:0645d8841f51 | 28 | |
bogdanm | 13:0645d8841f51 | 29 | static uint8_t repeated_start = 0; |
bogdanm | 13:0645d8841f51 | 30 | |
bogdanm | 13:0645d8841f51 | 31 | #define I2C_DAT(x) (x->i2c->MSTDAT) |
bogdanm | 13:0645d8841f51 | 32 | #define I2C_STAT(x) ((x->i2c->STAT >> 1) & (0x07)) |
bogdanm | 13:0645d8841f51 | 33 | |
bogdanm | 13:0645d8841f51 | 34 | static inline int i2c_status(i2c_t *obj) { |
bogdanm | 13:0645d8841f51 | 35 | return I2C_STAT(obj); |
bogdanm | 13:0645d8841f51 | 36 | } |
bogdanm | 13:0645d8841f51 | 37 | |
bogdanm | 13:0645d8841f51 | 38 | // Wait until the Serial Interrupt (SI) is set |
bogdanm | 13:0645d8841f51 | 39 | static int i2c_wait_SI(i2c_t *obj) { |
bogdanm | 13:0645d8841f51 | 40 | int timeout = 0; |
bogdanm | 13:0645d8841f51 | 41 | while (!(obj->i2c->STAT & (1 << 0))) { |
bogdanm | 13:0645d8841f51 | 42 | timeout++; |
bogdanm | 13:0645d8841f51 | 43 | if (timeout > 100000) return -1; |
bogdanm | 13:0645d8841f51 | 44 | } |
bogdanm | 13:0645d8841f51 | 45 | return 0; |
bogdanm | 13:0645d8841f51 | 46 | } |
bogdanm | 13:0645d8841f51 | 47 | |
bogdanm | 13:0645d8841f51 | 48 | static inline void i2c_interface_enable(i2c_t *obj) { |
bogdanm | 13:0645d8841f51 | 49 | obj->i2c->CFG |= (1 << 0); |
bogdanm | 13:0645d8841f51 | 50 | } |
bogdanm | 13:0645d8841f51 | 51 | |
bogdanm | 13:0645d8841f51 | 52 | static inline void i2c_power_enable(i2c_t *obj) { |
bogdanm | 13:0645d8841f51 | 53 | LPC_SYSCON->SYSAHBCLKCTRL |= (1<<5); |
bogdanm | 13:0645d8841f51 | 54 | LPC_SYSCON->PRESETCTRL &= ~(0x1<<6); |
bogdanm | 13:0645d8841f51 | 55 | LPC_SYSCON->PRESETCTRL |= (0x1<<6); |
bogdanm | 13:0645d8841f51 | 56 | } |
bogdanm | 13:0645d8841f51 | 57 | |
bogdanm | 13:0645d8841f51 | 58 | void i2c_init(i2c_t *obj, PinName sda, PinName scl) { |
bogdanm | 13:0645d8841f51 | 59 | obj->i2c = (LPC_I2C_TypeDef *)LPC_I2C; |
bogdanm | 13:0645d8841f51 | 60 | |
bogdanm | 13:0645d8841f51 | 61 | const SWM_Map *swm; |
bogdanm | 13:0645d8841f51 | 62 | uint32_t regVal; |
bogdanm | 13:0645d8841f51 | 63 | |
bogdanm | 13:0645d8841f51 | 64 | swm = &SWM_I2C_SDA[0]; |
bogdanm | 13:0645d8841f51 | 65 | regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset); |
bogdanm | 13:0645d8841f51 | 66 | LPC_SWM->PINASSIGN[swm->n] = regVal | (sda << swm->offset); |
bogdanm | 13:0645d8841f51 | 67 | |
bogdanm | 13:0645d8841f51 | 68 | swm = &SWM_I2C_SCL[0]; |
bogdanm | 13:0645d8841f51 | 69 | regVal = LPC_SWM->PINASSIGN[swm->n] & ~(0xFF << swm->offset); |
bogdanm | 13:0645d8841f51 | 70 | LPC_SWM->PINASSIGN[swm->n] = regVal | (scl << swm->offset); |
bogdanm | 13:0645d8841f51 | 71 | |
bogdanm | 13:0645d8841f51 | 72 | // enable power |
bogdanm | 13:0645d8841f51 | 73 | i2c_power_enable(obj); |
bogdanm | 13:0645d8841f51 | 74 | // set default frequency at 100k |
bogdanm | 13:0645d8841f51 | 75 | i2c_frequency(obj, 100000); |
bogdanm | 13:0645d8841f51 | 76 | i2c_interface_enable(obj); |
bogdanm | 13:0645d8841f51 | 77 | } |
bogdanm | 13:0645d8841f51 | 78 | |
bogdanm | 13:0645d8841f51 | 79 | inline int i2c_start(i2c_t *obj) { |
bogdanm | 13:0645d8841f51 | 80 | int status = 0; |
bogdanm | 13:0645d8841f51 | 81 | if (repeated_start) { |
bogdanm | 13:0645d8841f51 | 82 | obj->i2c->MSTCTL = (1 << 1) | (1 << 0); |
bogdanm | 13:0645d8841f51 | 83 | repeated_start = 0; |
bogdanm | 13:0645d8841f51 | 84 | } else { |
bogdanm | 13:0645d8841f51 | 85 | obj->i2c->MSTCTL = (1 << 1); |
bogdanm | 13:0645d8841f51 | 86 | } |
bogdanm | 13:0645d8841f51 | 87 | return status; |
bogdanm | 13:0645d8841f51 | 88 | } |
bogdanm | 13:0645d8841f51 | 89 | |
bogdanm | 13:0645d8841f51 | 90 | inline int i2c_stop(i2c_t *obj) { |
bogdanm | 13:0645d8841f51 | 91 | int timeout = 0; |
bogdanm | 13:0645d8841f51 | 92 | |
bogdanm | 13:0645d8841f51 | 93 | obj->i2c->MSTCTL = (1 << 2) | (1 << 0); |
bogdanm | 13:0645d8841f51 | 94 | while ((obj->i2c->STAT & ((1 << 0) | (7 << 1))) != ((1 << 0) | (0 << 1))) { |
bogdanm | 13:0645d8841f51 | 95 | timeout ++; |
bogdanm | 13:0645d8841f51 | 96 | if (timeout > 100000) return 1; |
bogdanm | 13:0645d8841f51 | 97 | } |
bogdanm | 13:0645d8841f51 | 98 | |
bogdanm | 13:0645d8841f51 | 99 | return 0; |
bogdanm | 13:0645d8841f51 | 100 | } |
bogdanm | 13:0645d8841f51 | 101 | |
bogdanm | 13:0645d8841f51 | 102 | |
bogdanm | 13:0645d8841f51 | 103 | static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) { |
bogdanm | 13:0645d8841f51 | 104 | // write the data |
bogdanm | 13:0645d8841f51 | 105 | I2C_DAT(obj) = value; |
bogdanm | 13:0645d8841f51 | 106 | |
bogdanm | 13:0645d8841f51 | 107 | if (!addr) |
bogdanm | 13:0645d8841f51 | 108 | obj->i2c->MSTCTL = (1 << 0); |
bogdanm | 13:0645d8841f51 | 109 | |
bogdanm | 13:0645d8841f51 | 110 | // wait and return status |
bogdanm | 13:0645d8841f51 | 111 | i2c_wait_SI(obj); |
bogdanm | 13:0645d8841f51 | 112 | return i2c_status(obj); |
bogdanm | 13:0645d8841f51 | 113 | } |
bogdanm | 13:0645d8841f51 | 114 | |
bogdanm | 13:0645d8841f51 | 115 | static inline int i2c_do_read(i2c_t *obj, int last) { |
bogdanm | 13:0645d8841f51 | 116 | // wait for it to arrive |
bogdanm | 13:0645d8841f51 | 117 | i2c_wait_SI(obj); |
bogdanm | 13:0645d8841f51 | 118 | if (!last) |
bogdanm | 13:0645d8841f51 | 119 | obj->i2c->MSTCTL = (1 << 0); |
bogdanm | 13:0645d8841f51 | 120 | |
bogdanm | 13:0645d8841f51 | 121 | // return the data |
bogdanm | 13:0645d8841f51 | 122 | return (I2C_DAT(obj) & 0xFF); |
bogdanm | 13:0645d8841f51 | 123 | } |
bogdanm | 13:0645d8841f51 | 124 | |
bogdanm | 13:0645d8841f51 | 125 | void i2c_frequency(i2c_t *obj, int hz) { |
bogdanm | 13:0645d8841f51 | 126 | // No peripheral clock divider on the M0 |
bogdanm | 13:0645d8841f51 | 127 | uint32_t PCLK = SystemCoreClock; |
bogdanm | 13:0645d8841f51 | 128 | |
bogdanm | 13:0645d8841f51 | 129 | uint32_t clkdiv = PCLK / (hz * 4) - 1; |
bogdanm | 13:0645d8841f51 | 130 | |
bogdanm | 13:0645d8841f51 | 131 | obj->i2c->DIV = clkdiv; |
bogdanm | 13:0645d8841f51 | 132 | obj->i2c->MSTTIME = 0; |
bogdanm | 13:0645d8841f51 | 133 | } |
bogdanm | 13:0645d8841f51 | 134 | |
bogdanm | 13:0645d8841f51 | 135 | // The I2C does a read or a write as a whole operation |
bogdanm | 13:0645d8841f51 | 136 | // There are two types of error conditions it can encounter |
bogdanm | 13:0645d8841f51 | 137 | // 1) it can not obtain the bus |
bogdanm | 13:0645d8841f51 | 138 | // 2) it gets error responses at part of the transmission |
bogdanm | 13:0645d8841f51 | 139 | // |
bogdanm | 13:0645d8841f51 | 140 | // We tackle them as follows: |
bogdanm | 13:0645d8841f51 | 141 | // 1) we retry until we get the bus. we could have a "timeout" if we can not get it |
bogdanm | 13:0645d8841f51 | 142 | // which basically turns it in to a 2) |
bogdanm | 13:0645d8841f51 | 143 | // 2) on error, we use the standard error mechanisms to report/debug |
bogdanm | 13:0645d8841f51 | 144 | // |
bogdanm | 13:0645d8841f51 | 145 | // Therefore an I2C transaction should always complete. If it doesn't it is usually |
bogdanm | 13:0645d8841f51 | 146 | // because something is setup wrong (e.g. wiring), and we don't need to programatically |
bogdanm | 13:0645d8841f51 | 147 | // check for that |
bogdanm | 13:0645d8841f51 | 148 | |
bogdanm | 13:0645d8841f51 | 149 | int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) { |
bogdanm | 13:0645d8841f51 | 150 | int count, status; |
bogdanm | 13:0645d8841f51 | 151 | |
bogdanm | 13:0645d8841f51 | 152 | i2c_start(obj); |
bogdanm | 13:0645d8841f51 | 153 | |
bogdanm | 13:0645d8841f51 | 154 | status = i2c_do_write(obj, (address | 0x01), 1); |
bogdanm | 13:0645d8841f51 | 155 | if (status != 0x01) { |
bogdanm | 13:0645d8841f51 | 156 | i2c_stop(obj); |
bogdanm | 13:0645d8841f51 | 157 | return I2C_ERROR_NO_SLAVE; |
bogdanm | 13:0645d8841f51 | 158 | } |
bogdanm | 13:0645d8841f51 | 159 | |
bogdanm | 13:0645d8841f51 | 160 | // Read in all except last byte |
bogdanm | 13:0645d8841f51 | 161 | for (count = 0; count < (length - 1); count++) { |
bogdanm | 13:0645d8841f51 | 162 | int value = i2c_do_read(obj, 0); |
bogdanm | 13:0645d8841f51 | 163 | status = i2c_status(obj); |
bogdanm | 13:0645d8841f51 | 164 | if (status != 0x00) { |
bogdanm | 13:0645d8841f51 | 165 | i2c_stop(obj); |
bogdanm | 13:0645d8841f51 | 166 | return count; |
bogdanm | 13:0645d8841f51 | 167 | } |
bogdanm | 13:0645d8841f51 | 168 | data[count] = (char) value; |
bogdanm | 13:0645d8841f51 | 169 | } |
bogdanm | 13:0645d8841f51 | 170 | |
bogdanm | 13:0645d8841f51 | 171 | // read in last byte |
bogdanm | 13:0645d8841f51 | 172 | int value = i2c_do_read(obj, 1); |
bogdanm | 13:0645d8841f51 | 173 | status = i2c_status(obj); |
bogdanm | 13:0645d8841f51 | 174 | if (status != 0x01) { |
bogdanm | 13:0645d8841f51 | 175 | i2c_stop(obj); |
bogdanm | 13:0645d8841f51 | 176 | return length - 1; |
bogdanm | 13:0645d8841f51 | 177 | } |
bogdanm | 13:0645d8841f51 | 178 | |
bogdanm | 13:0645d8841f51 | 179 | data[count] = (char) value; |
bogdanm | 13:0645d8841f51 | 180 | |
bogdanm | 13:0645d8841f51 | 181 | // If not repeated start, send stop. |
bogdanm | 13:0645d8841f51 | 182 | if (stop) { |
bogdanm | 13:0645d8841f51 | 183 | i2c_stop(obj); |
bogdanm | 13:0645d8841f51 | 184 | } else { |
bogdanm | 13:0645d8841f51 | 185 | repeated_start = 1; |
bogdanm | 13:0645d8841f51 | 186 | } |
bogdanm | 13:0645d8841f51 | 187 | |
bogdanm | 13:0645d8841f51 | 188 | return length; |
bogdanm | 13:0645d8841f51 | 189 | } |
bogdanm | 13:0645d8841f51 | 190 | |
bogdanm | 13:0645d8841f51 | 191 | int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) { |
bogdanm | 13:0645d8841f51 | 192 | int i, status; |
bogdanm | 13:0645d8841f51 | 193 | |
bogdanm | 13:0645d8841f51 | 194 | i2c_start(obj); |
bogdanm | 13:0645d8841f51 | 195 | |
bogdanm | 13:0645d8841f51 | 196 | status = i2c_do_write(obj, (address & 0xFE), 1); |
bogdanm | 13:0645d8841f51 | 197 | if (status != 0x02) { |
bogdanm | 13:0645d8841f51 | 198 | i2c_stop(obj); |
bogdanm | 13:0645d8841f51 | 199 | return I2C_ERROR_NO_SLAVE; |
bogdanm | 13:0645d8841f51 | 200 | } |
bogdanm | 13:0645d8841f51 | 201 | |
bogdanm | 13:0645d8841f51 | 202 | for (i=0; i<length; i++) { |
bogdanm | 13:0645d8841f51 | 203 | status = i2c_do_write(obj, data[i], 0); |
bogdanm | 13:0645d8841f51 | 204 | if (status != 0x02) { |
bogdanm | 13:0645d8841f51 | 205 | i2c_stop(obj); |
bogdanm | 13:0645d8841f51 | 206 | return i; |
bogdanm | 13:0645d8841f51 | 207 | } |
bogdanm | 13:0645d8841f51 | 208 | } |
bogdanm | 13:0645d8841f51 | 209 | |
bogdanm | 13:0645d8841f51 | 210 | // If not repeated start, send stop. |
bogdanm | 13:0645d8841f51 | 211 | if (stop) { |
bogdanm | 13:0645d8841f51 | 212 | i2c_stop(obj); |
bogdanm | 13:0645d8841f51 | 213 | } else { |
bogdanm | 13:0645d8841f51 | 214 | repeated_start = 1; |
bogdanm | 13:0645d8841f51 | 215 | } |
bogdanm | 13:0645d8841f51 | 216 | |
bogdanm | 13:0645d8841f51 | 217 | return length; |
bogdanm | 13:0645d8841f51 | 218 | } |
bogdanm | 13:0645d8841f51 | 219 | |
bogdanm | 13:0645d8841f51 | 220 | void i2c_reset(i2c_t *obj) { |
bogdanm | 13:0645d8841f51 | 221 | i2c_stop(obj); |
bogdanm | 13:0645d8841f51 | 222 | } |
bogdanm | 13:0645d8841f51 | 223 | |
bogdanm | 13:0645d8841f51 | 224 | int i2c_byte_read(i2c_t *obj, int last) { |
bogdanm | 13:0645d8841f51 | 225 | return (i2c_do_read(obj, last) & 0xFF); |
bogdanm | 13:0645d8841f51 | 226 | } |
bogdanm | 13:0645d8841f51 | 227 | |
bogdanm | 13:0645d8841f51 | 228 | int i2c_byte_write(i2c_t *obj, int data) { |
bogdanm | 13:0645d8841f51 | 229 | int ack; |
bogdanm | 13:0645d8841f51 | 230 | int status = i2c_do_write(obj, (data & 0xFF), 0); |
bogdanm | 13:0645d8841f51 | 231 | |
bogdanm | 13:0645d8841f51 | 232 | switch(status) { |
bogdanm | 13:0645d8841f51 | 233 | case 2: |
bogdanm | 13:0645d8841f51 | 234 | ack = 1; |
bogdanm | 13:0645d8841f51 | 235 | break; |
bogdanm | 13:0645d8841f51 | 236 | default: |
bogdanm | 13:0645d8841f51 | 237 | ack = 0; |
bogdanm | 13:0645d8841f51 | 238 | break; |
bogdanm | 13:0645d8841f51 | 239 | } |
bogdanm | 13:0645d8841f51 | 240 | |
bogdanm | 13:0645d8841f51 | 241 | return ack; |
bogdanm | 13:0645d8841f51 | 242 | } |