mbed library sources modified for open wear
Dependents: openwear-lifelogger-example
Fork of mbed-src by
targets/hal/TARGET_Freescale/TARGET_K20D5M/i2c_api.c
- Committer:
- mbed_official
- Date:
- 2013-12-26
- Revision:
- 68:41613245dfd7
- Child:
- 73:299c67215126
File content as of revision 68:41613245dfd7:
/* 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 "i2c_api.h" #include "cmsis.h" #include "pinmap.h" #include "error.h" static const PinMap PinMap_I2C_SDA[] = { {PTB1, I2C_0, 2}, {PTB3, I2C_0, 2}, {NC , NC , 0} }; static const PinMap PinMap_I2C_SCL[] = { {PTB0, I2C_0, 2}, {PTB2, I2C_0, 2}, {NC , NC, 0} }; static const uint16_t ICR[0x40] = { 20, 22, 24, 26, 28, 30, 34, 40, 28, 32, 36, 40, 44, 48, 56, 68, 48, 56, 64, 72, 80, 88, 104, 128, 80, 96, 112, 128, 144, 160, 192, 240, 160, 192, 224, 256, 288, 320, 384, 480, 320, 384, 448, 512, 576, 640, 768, 960, 640, 768, 896, 1024, 1152, 1280, 1536, 1920, 1280, 1536, 1792, 2048, 2304, 2560, 3072, 3840 }; static uint8_t first_read; void i2c_init(i2c_t *obj, PinName sda, PinName scl) { // determine the I2C to use I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA); I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL); obj->i2c = (I2C_Type*)pinmap_merge(i2c_sda, i2c_scl); if ((int)obj->i2c == NC) error("I2C pin mapping failed"); SIM->SCGC4 |= SIM_SCGC4_I2C0_MASK; SIM->SCGC5 |= SIM_SCGC5_PORTB_MASK; // set default frequency at 100k i2c_frequency(obj, 100000); // enable I2C interface obj->i2c->C1 |= 0x80; pinmap_pinout(sda, PinMap_I2C_SDA); pinmap_pinout(scl, PinMap_I2C_SCL); first_read = 1; } int i2c_start(i2c_t *obj) { // if we are in the middle of a transaction // activate the repeat_start flag if (obj->i2c->S & I2C_S_BUSY_MASK) { obj->i2c->C1 |= 0x04; } else { obj->i2c->C1 |= I2C_C1_MST_MASK; obj->i2c->C1 |= I2C_C1_TX_MASK; } first_read = 1; return 0; } int i2c_stop(i2c_t *obj) { volatile uint32_t n = 0; obj->i2c->C1 &= ~I2C_C1_MST_MASK; obj->i2c->C1 &= ~I2C_C1_TX_MASK; // It seems that there are timing problems // when there is no waiting time after a STOP. // This wait is also included on the samples // code provided with the freedom board for (n = 0; n < 100; n++) __NOP(); first_read = 1; return 0; } static int timeout_status_poll(i2c_t *obj, uint32_t mask) { uint32_t i, timeout = 1000; for (i = 0; i < timeout; i++) { if (obj->i2c->S & mask) return 0; } return 1; } // this function waits the end of a tx transfer and return the status of the transaction: // 0: OK ack received // 1: OK ack not received // 2: failure static int i2c_wait_end_tx_transfer(i2c_t *obj) { // wait for the interrupt flag if (timeout_status_poll(obj, I2C_S_IICIF_MASK)) { return 2; } obj->i2c->S |= I2C_S_IICIF_MASK; // wait transfer complete if (timeout_status_poll(obj, I2C_S_TCF_MASK)) { return 2; } // check if we received the ACK or not return obj->i2c->S & I2C_S_RXAK_MASK ? 1 : 0; } // this function waits the end of a rx transfer and return the status of the transaction: // 0: OK // 1: failure static int i2c_wait_end_rx_transfer(i2c_t *obj) { // wait for the end of the rx transfer if (timeout_status_poll(obj, I2C_S_IICIF_MASK)) { return 1; } obj->i2c->S |= I2C_S_IICIF_MASK; return 0; } static void i2c_send_nack(i2c_t *obj) { obj->i2c->C1 |= I2C_C1_TXAK_MASK; // NACK } static void i2c_send_ack(i2c_t *obj) { obj->i2c->C1 &= ~I2C_C1_TXAK_MASK; // ACK } static int i2c_do_write(i2c_t *obj, int value) { // write the data obj->i2c->D = value; // init and wait the end of the transfer return i2c_wait_end_tx_transfer(obj); } static int i2c_do_read(i2c_t *obj, char * data, int last) { if (last) i2c_send_nack(obj); else i2c_send_ack(obj); *data = (obj->i2c->D & 0xFF); // start rx transfer and wait the end of the transfer return i2c_wait_end_rx_transfer(obj); } void i2c_frequency(i2c_t *obj, int hz) { uint8_t icr = 0; uint8_t mult = 0; uint32_t error = 0; uint32_t p_error = 0xffffffff; uint32_t ref = 0; uint8_t i, j; // bus clk uint32_t PCLK = 24000000u; uint32_t pulse = PCLK / (hz * 2); // we look for the values that minimize the error // test all the MULT values for (i = 1; i < 5; i*=2) { for (j = 0; j < 0x40; j++) { ref = PCLK / (i*ICR[j]); if (ref > (uint32_t)hz) continue; error = hz - ref; if (error < p_error) { icr = j; mult = i/2; p_error = error; } } } pulse = icr | (mult << 6); // I2C Rate obj->i2c->F = pulse; } int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) { int count; char dummy_read, *ptr; if (i2c_start(obj)) { i2c_stop(obj); return I2C_ERROR_BUS_BUSY; } if (i2c_do_write(obj, (address | 0x01))) { i2c_stop(obj); return I2C_ERROR_NO_SLAVE; } // set rx mode obj->i2c->C1 &= ~I2C_C1_TX_MASK; // Read in bytes for (count = 0; count < (length); count++) { ptr = (count == 0) ? &dummy_read : &data[count - 1]; uint8_t stop_ = (count == (length - 1)) ? 1 : 0; if (i2c_do_read(obj, ptr, stop_)) { i2c_stop(obj); return count; } } // If not repeated start, send stop. if (stop) { i2c_stop(obj); } // last read data[count-1] = obj->i2c->D; return length; } int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) { int i; if (i2c_start(obj)) { i2c_stop(obj); return I2C_ERROR_BUS_BUSY; } if (i2c_do_write(obj, (address & 0xFE))) { i2c_stop(obj); return I2C_ERROR_NO_SLAVE; } for (i = 0; i < length; i++) { if(i2c_do_write(obj, data[i])) { i2c_stop(obj); return i; } } if (stop) i2c_stop(obj); return length; } void i2c_reset(i2c_t *obj) { i2c_stop(obj); } int i2c_byte_read(i2c_t *obj, int last) { char data; // set rx mode obj->i2c->C1 &= ~I2C_C1_TX_MASK; if(first_read) { // first dummy read i2c_do_read(obj, &data, 0); first_read = 0; } if (last) { // set tx mode obj->i2c->C1 |= I2C_C1_TX_MASK; return obj->i2c->D; } i2c_do_read(obj, &data, last); return data; } int i2c_byte_write(i2c_t *obj, int data) { first_read = 1; // set tx mode obj->i2c->C1 |= I2C_C1_TX_MASK; return !i2c_do_write(obj, (data & 0xFF)); } #if DEVICE_I2CSLAVE void i2c_slave_mode(i2c_t *obj, int enable_slave) { if (enable_slave) { // set slave mode obj->i2c->C1 &= ~I2C_C1_MST_MASK; obj->i2c->C1 |= I2C_C1_IICIE_MASK; } else { // set master mode obj->i2c->C1 |= I2C_C1_MST_MASK; } } int i2c_slave_receive(i2c_t *obj) { switch(obj->i2c->S) { // read addressed case 0xE6: return 1; // write addressed case 0xE2: return 3; default: return 0; } } int i2c_slave_read(i2c_t *obj, char *data, int length) { uint8_t dummy_read; uint8_t * ptr; int count; // set rx mode obj->i2c->C1 &= ~I2C_C1_TX_MASK; // first dummy read dummy_read = obj->i2c->D; if (i2c_wait_end_rx_transfer(obj)) return 0; // read address dummy_read = obj->i2c->D; if (i2c_wait_end_rx_transfer(obj)) return 0; // read (length - 1) bytes for (count = 0; count < (length - 1); count++) { data[count] = obj->i2c->D; if (i2c_wait_end_rx_transfer(obj)) return count; } // read last byte ptr = (length == 0) ? &dummy_read : (uint8_t *)&data[count]; *ptr = obj->i2c->D; return (length) ? (count + 1) : 0; } int i2c_slave_write(i2c_t *obj, const char *data, int length) { int i, count = 0; // set tx mode obj->i2c->C1 |= I2C_C1_TX_MASK; for (i = 0; i < length; i++) { if (i2c_do_write(obj, data[count++]) == 2) return i; } // set rx mode obj->i2c->C1 &= ~I2C_C1_TX_MASK; // dummy rx transfer needed // otherwise the master cannot generate a stop bit obj->i2c->D; if (i2c_wait_end_rx_transfer(obj) == 2) return count; return count; } void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) { obj->i2c->A1 = address & 0xfe; } #endif