1 /* mbed Microcontroller Library
2 * Copyright (c) 2006-2013 ARM Limited
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 #include "mbed_assert.h"
21 static uint8_t repeated_start = 0;
23 #define I2C_STAT(x) ((LPC_I2C0->STAT >> 1) & (0x07))
25 static inline int i2c_status(i2c_t *obj) {
29 // Wait until the Serial Interrupt (SI) is set
30 static int i2c_wait_SI(i2c_t *obj) {
31 volatile int timeout = 0;
32 while (!(LPC_I2C0->STAT & (1 << 0))) {
34 if (timeout > 100000) return -1;
39 static inline void i2c_interface_enable(i2c_t *obj) {
40 LPC_I2C0->CFG |= (1 << 0);
43 void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
44 MBED_ASSERT((sda == P0_23) && (scl == P0_22));
46 // Enables clock for I2C0
47 LPC_SYSCON->SYSAHBCLKCTRL1 |= (1 << 13);
49 LPC_SYSCON->PRESETCTRL1 |= (1 << 13);
50 LPC_SYSCON->PRESETCTRL1 &= ~(1 << 13);
53 LPC_SWM->PINENABLE1 &= ~(0x3 << 3);
55 // set default frequency at 100kHz
56 i2c_frequency(obj, 100000);
57 i2c_interface_enable(obj);
60 inline int i2c_start(i2c_t *obj) {
63 LPC_I2C0->MSTCTL = (1 << 1) | (1 << 0);
66 LPC_I2C0->MSTCTL = (1 << 1);
71 inline int i2c_stop(i2c_t *obj) {
72 volatile int timeout = 0;
74 LPC_I2C0->MSTCTL = (1 << 2) | (1 << 0);
75 while ((LPC_I2C0->STAT & ((1 << 0) | (7 << 1))) != ((1 << 0) | (0 << 1))) {
77 if (timeout > 100000) return 1;
84 static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) {
86 LPC_I2C0->MSTDAT = value;
89 LPC_I2C0->MSTCTL = (1 << 0);
91 // wait and return status
93 return i2c_status(obj);
96 static inline int i2c_do_read(i2c_t *obj, int last) {
97 // wait for it to arrive
100 LPC_I2C0->MSTCTL = (1 << 0);
103 return (LPC_I2C0->MSTDAT & 0xFF);
106 void i2c_frequency(i2c_t *obj, int hz) {
107 // No peripheral clock divider on the M0
108 uint32_t PCLK = SystemCoreClock;
109 uint32_t clkdiv = PCLK / (hz * 4) - 1;
111 LPC_I2C0->DIV = clkdiv;
112 LPC_I2C0->MSTTIME = 0;
115 int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
120 LPC_I2C0->MSTDAT = (address | 0x01);
121 LPC_I2C0->MSTCTL |= 0x20;
122 if (i2c_wait_SI(obj) == -1)
125 status = ((LPC_I2C0->STAT >> 1) & (0x07));
126 if (status != 0x01) {
128 return I2C_ERROR_NO_SLAVE;
131 // Read in all except last byte
132 for (count = 0; count < (length - 1); count++) {
133 if (i2c_wait_SI(obj) == -1)
135 LPC_I2C0->MSTCTL = (1 << 0);
136 data[count] = (LPC_I2C0->MSTDAT & 0xFF);
137 status = ((LPC_I2C0->STAT >> 1) & (0x07));
138 if (status != 0x01) {
145 if (i2c_wait_SI(obj) == -1)
148 data[count] = (LPC_I2C0->MSTDAT & 0xFF);
149 status = i2c_status(obj);
150 if (status != 0x01) {
154 // If not repeated start, send stop.
164 int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
169 LPC_I2C0->MSTDAT = (address & 0xFE);
170 LPC_I2C0->MSTCTL |= 0x20;
171 if (i2c_wait_SI(obj) == -1)
174 status = ((LPC_I2C0->STAT >> 1) & (0x07));
175 if (status != 0x02) {
177 return I2C_ERROR_NO_SLAVE;
180 for (i=0; i<length; i++) {
181 LPC_I2C0->MSTDAT = data[i];
182 LPC_I2C0->MSTCTL = (1 << 0);
183 if (i2c_wait_SI(obj) == -1)
186 status = ((LPC_I2C0->STAT >> 1) & (0x07));
187 if (status != 0x02) {
193 // If not repeated start, send stop.
203 void i2c_reset(i2c_t *obj) {
207 int i2c_byte_read(i2c_t *obj, int last) {
208 return (i2c_do_read(obj, last) & 0xFF);
211 int i2c_byte_write(i2c_t *obj, int data) {
212 if (i2c_do_write(obj, (data & 0xFF), 0) == 2) {