mbed library sources
Dependents: frdm_kl05z_gpio_test
Fork of mbed-src by
targets/hal/TARGET_NXP/TARGET_LPC15XX/i2c_api.c
- Committer:
- shaoziyang
- Date:
- 2014-09-13
- Revision:
- 323:9e901b0a5aa1
- Parent:
- 257:9258cc0a200d
File content as of revision 323:9e901b0a5aa1:
/* 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 "mbed_assert.h" #include "i2c_api.h" #include "cmsis.h" #include "pinmap.h" static uint8_t repeated_start = 0; #define I2C_STAT(x) ((LPC_I2C0->STAT >> 1) & (0x07)) static inline int i2c_status(i2c_t *obj) { return I2C_STAT(obj); } // Wait until the Serial Interrupt (SI) is set static int i2c_wait_SI(i2c_t *obj) { volatile int timeout = 0; while (!(LPC_I2C0->STAT & (1 << 0))) { timeout++; if (timeout > 100000) return -1; } return 0; } static inline void i2c_interface_enable(i2c_t *obj) { LPC_I2C0->CFG |= (1 << 0); } void i2c_init(i2c_t *obj, PinName sda, PinName scl) { MBED_ASSERT((sda == P0_23) && (scl == P0_22)); // Enables clock for I2C0 LPC_SYSCON->SYSAHBCLKCTRL1 |= (1 << 13); LPC_SYSCON->PRESETCTRL1 |= (1 << 13); LPC_SYSCON->PRESETCTRL1 &= ~(1 << 13); // pin enable LPC_SWM->PINENABLE1 &= ~(0x3 << 3); // set default frequency at 100kHz i2c_frequency(obj, 100000); i2c_interface_enable(obj); } inline int i2c_start(i2c_t *obj) { int status = 0; if (repeated_start) { LPC_I2C0->MSTCTL = (1 << 1) | (1 << 0); repeated_start = 0; } else { LPC_I2C0->MSTCTL = (1 << 1); } return status; } inline int i2c_stop(i2c_t *obj) { volatile int timeout = 0; LPC_I2C0->MSTCTL = (1 << 2) | (1 << 0); while ((LPC_I2C0->STAT & ((1 << 0) | (7 << 1))) != ((1 << 0) | (0 << 1))) { timeout ++; if (timeout > 100000) return 1; } return 0; } static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) { // write the data LPC_I2C0->MSTDAT = value; if (!addr) LPC_I2C0->MSTCTL = (1 << 0); // wait and return status i2c_wait_SI(obj); return i2c_status(obj); } static inline int i2c_do_read(i2c_t *obj, int last) { // wait for it to arrive i2c_wait_SI(obj); if (!last) LPC_I2C0->MSTCTL = (1 << 0); // return the data return (LPC_I2C0->MSTDAT & 0xFF); } void i2c_frequency(i2c_t *obj, int hz) { // No peripheral clock divider on the M0 uint32_t PCLK = SystemCoreClock; uint32_t clkdiv = PCLK / (hz * 4) - 1; LPC_I2C0->DIV = clkdiv; LPC_I2C0->MSTTIME = 0; } int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) { int count, status; i2c_start(obj); LPC_I2C0->MSTDAT = (address | 0x01); LPC_I2C0->MSTCTL |= 0x20; if (i2c_wait_SI(obj) == -1) return -1; status = ((LPC_I2C0->STAT >> 1) & (0x07)); if (status != 0x01) { i2c_stop(obj); return I2C_ERROR_NO_SLAVE; } // Read in all except last byte for (count = 0; count < (length - 1); count++) { if (i2c_wait_SI(obj) == -1) return -1; LPC_I2C0->MSTCTL = (1 << 0); data[count] = (LPC_I2C0->MSTDAT & 0xFF); status = ((LPC_I2C0->STAT >> 1) & (0x07)); if (status != 0x01) { i2c_stop(obj); return count; } } // read in last byte if (i2c_wait_SI(obj) == -1) return -1; data[count] = (LPC_I2C0->MSTDAT & 0xFF); status = i2c_status(obj); if (status != 0x01) { i2c_stop(obj); return length - 1; } // If not repeated start, send stop. if (stop) { i2c_stop(obj); } else { repeated_start = 1; } return length; } int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) { int i, status; i2c_start(obj); LPC_I2C0->MSTDAT = (address & 0xFE); LPC_I2C0->MSTCTL |= 0x20; if (i2c_wait_SI(obj) == -1) return -1; status = ((LPC_I2C0->STAT >> 1) & (0x07)); if (status != 0x02) { i2c_stop(obj); return I2C_ERROR_NO_SLAVE; } for (i=0; i<length; i++) { LPC_I2C0->MSTDAT = data[i]; LPC_I2C0->MSTCTL = (1 << 0); if (i2c_wait_SI(obj) == -1) return -1; status = ((LPC_I2C0->STAT >> 1) & (0x07)); if (status != 0x02) { i2c_stop(obj); return i; } } // If not repeated start, send stop. if (stop) { i2c_stop(obj); } else { repeated_start = 1; } return length; } void i2c_reset(i2c_t *obj) { i2c_stop(obj); } int i2c_byte_read(i2c_t *obj, int last) { return (i2c_do_read(obj, last) & 0xFF); } int i2c_byte_write(i2c_t *obj, int data) { if (i2c_do_write(obj, (data & 0xFF), 0) == 2) { return 1; } else { return 0; } }