mbed library sources modified for open wear
Dependents: openwear-lifelogger-example
Fork of mbed-src by
targets/hal/TARGET_NXP/TARGET_LPC176X/i2c_api.c
- Committer:
- bogdanm
- Date:
- 2013-08-05
- Revision:
- 13:0645d8841f51
- Child:
- 227:7bd0639b8911
File content as of revision 13:0645d8841f51:
/* 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[] = { {P0_0 , I2C_1, 3}, {P0_10, I2C_2, 2}, {P0_19, I2C_1, 3}, {P0_27, I2C_0, 1}, {NC , NC , 0} }; static const PinMap PinMap_I2C_SCL[] = { {P0_1 , I2C_1, 3}, {P0_11, I2C_2, 2}, {P0_20, I2C_1, 3}, {P0_28, I2C_0, 1}, {NC , NC, 0} }; #define I2C_CONSET(x) (x->i2c->I2CONSET) #define I2C_CONCLR(x) (x->i2c->I2CONCLR) #define I2C_STAT(x) (x->i2c->I2STAT) #define I2C_DAT(x) (x->i2c->I2DAT) #define I2C_SCLL(x, val) (x->i2c->I2SCLL = val) #define I2C_SCLH(x, val) (x->i2c->I2SCLH = val) static const uint32_t I2C_addr_offset[2][4] = { {0x0C, 0x20, 0x24, 0x28}, {0x30, 0x34, 0x38, 0x3C} }; static inline void i2c_conclr(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) { I2C_CONCLR(obj) = (start << 5) | (stop << 4) | (interrupt << 3) | (acknowledge << 2); } static inline void i2c_conset(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) { I2C_CONSET(obj) = (start << 5) | (stop << 4) | (interrupt << 3) | (acknowledge << 2); } // Clear the Serial Interrupt (SI) static inline void i2c_clear_SI(i2c_t *obj) { i2c_conclr(obj, 0, 0, 1, 0); } 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) { int timeout = 0; while (!(I2C_CONSET(obj) & (1 << 3))) { timeout++; if (timeout > 100000) return -1; } return 0; } static inline void i2c_interface_enable(i2c_t *obj) { I2C_CONSET(obj) = 0x40; } static inline void i2c_power_enable(i2c_t *obj) { switch ((int)obj->i2c) { case I2C_0: LPC_SC->PCONP |= 1 << 7; break; case I2C_1: LPC_SC->PCONP |= 1 << 19; break; case I2C_2: LPC_SC->PCONP |= 1 << 26; break; } } void i2c_init(i2c_t *obj, PinName sda, PinName scl) { // determine the SPI to use I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA); I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL); obj->i2c = (LPC_I2C_TypeDef *)pinmap_merge(i2c_sda, i2c_scl); if ((int)obj->i2c == NC) { error("I2C pin mapping failed"); } // enable power i2c_power_enable(obj); // set default frequency at 100k i2c_frequency(obj, 100000); i2c_conclr(obj, 1, 1, 1, 1); i2c_interface_enable(obj); pinmap_pinout(sda, PinMap_I2C_SDA); pinmap_pinout(scl, PinMap_I2C_SCL); } inline int i2c_start(i2c_t *obj) { int status = 0; // 8.1 Before master mode can be entered, I2CON must be initialised to: // - I2EN STA STO SI AA - - // - 1 0 0 0 x - - // if AA = 0, it can't enter slave mode i2c_conclr(obj, 1, 1, 1, 1); // The master mode may now be entered by setting the STA bit // this will generate a start condition when the bus becomes free i2c_conset(obj, 1, 0, 0, 1); i2c_wait_SI(obj); status = i2c_status(obj); // Clear start bit now transmitted, and interrupt bit i2c_conclr(obj, 1, 0, 0, 0); return status; } inline int i2c_stop(i2c_t *obj) { int timeout = 0; // write the stop bit i2c_conset(obj, 0, 1, 0, 0); i2c_clear_SI(obj); // wait for STO bit to reset while(I2C_CONSET(obj) & (1 << 4)) { 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 I2C_DAT(obj) = value; // clear SI to init a send i2c_clear_SI(obj); // wait and return status i2c_wait_SI(obj); return i2c_status(obj); } static inline int i2c_do_read(i2c_t *obj, int last) { // we are in state 0x40 (SLA+R tx'd) or 0x50 (data rx'd and ack) if(last) { i2c_conclr(obj, 0, 0, 0, 1); // send a NOT ACK } else { i2c_conset(obj, 0, 0, 0, 1); // send a ACK } // accept byte i2c_clear_SI(obj); // wait for it to arrive i2c_wait_SI(obj); // return the data return (I2C_DAT(obj) & 0xFF); } void i2c_frequency(i2c_t *obj, int hz) { // [TODO] set pclk to /4 uint32_t PCLK = SystemCoreClock / 4; uint32_t pulse = PCLK / (hz * 2); // I2C Rate I2C_SCLL(obj, pulse); I2C_SCLH(obj, pulse); } // The I2C does a read or a write as a whole operation // There are two types of error conditions it can encounter // 1) it can not obtain the bus // 2) it gets error responses at part of the transmission // // We tackle them as follows: // 1) we retry until we get the bus. we could have a "timeout" if we can not get it // which basically turns it in to a 2) // 2) on error, we use the standard error mechanisms to report/debug // // Therefore an I2C transaction should always complete. If it doesn't it is usually // because something is setup wrong (e.g. wiring), and we don't need to programatically // check for that int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) { int count, status; status = i2c_start(obj); if ((status != 0x10) && (status != 0x08)) { i2c_stop(obj); return I2C_ERROR_BUS_BUSY; } status = i2c_do_write(obj, (address | 0x01), 1); if (status != 0x40) { i2c_stop(obj); return I2C_ERROR_NO_SLAVE; } // Read in all except last byte for (count = 0; count < (length - 1); count++) { int value = i2c_do_read(obj, 0); status = i2c_status(obj); if (status != 0x50) { i2c_stop(obj); return count; } data[count] = (char) value; } // read in last byte int value = i2c_do_read(obj, 1); status = i2c_status(obj); if (status != 0x58) { i2c_stop(obj); return length - 1; } data[count] = (char) value; // If not repeated start, send stop. if (stop) { i2c_stop(obj); } return length; } int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) { int i, status; status = i2c_start(obj); if ((status != 0x10) && (status != 0x08)) { i2c_stop(obj); return I2C_ERROR_BUS_BUSY; } status = i2c_do_write(obj, (address & 0xFE), 1); if (status != 0x18) { i2c_stop(obj); return I2C_ERROR_NO_SLAVE; } for (i=0; i<length; i++) { status = i2c_do_write(obj, data[i], 0); if(status != 0x28) { i2c_stop(obj); return i; } } // clearing the serial interrupt here might cause an unintended rewrite of the last byte // see also issue report https://mbed.org/users/mbed_official/code/mbed/issues/1 // i2c_clear_SI(obj); // If not repeated start, send stop. 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) { return (i2c_do_read(obj, last) & 0xFF); } int i2c_byte_write(i2c_t *obj, int data) { int ack; int status = i2c_do_write(obj, (data & 0xFF), 0); switch(status) { case 0x18: case 0x28: // Master transmit ACKs ack = 1; break; case 0x40: // Master receive address transmitted ACK ack = 1; break; case 0xB8: // Slave transmit ACK ack = 1; break; default: ack = 0; break; } return ack; } void i2c_slave_mode(i2c_t *obj, int enable_slave) { if (enable_slave != 0) { i2c_conclr(obj, 1, 1, 1, 0); i2c_conset(obj, 0, 0, 0, 1); } else { i2c_conclr(obj, 1, 1, 1, 1); } } int i2c_slave_receive(i2c_t *obj) { int status; int retval; status = i2c_status(obj); switch(status) { case 0x60: retval = 3; break; case 0x70: retval = 2; break; case 0xA8: retval = 1; break; default : retval = 0; break; } return(retval); } int i2c_slave_read(i2c_t *obj, char *data, int length) { int count = 0; int status; do { i2c_clear_SI(obj); i2c_wait_SI(obj); status = i2c_status(obj); if((status == 0x80) || (status == 0x90)) { data[count] = I2C_DAT(obj) & 0xFF; } count++; } while (((status == 0x80) || (status == 0x90) || (status == 0x060) || (status == 0x70)) && (count < length)); if(status != 0xA0) { i2c_stop(obj); } i2c_clear_SI(obj); return count; } int i2c_slave_write(i2c_t *obj, const char *data, int length) { int count = 0; int status; if(length <= 0) { return(0); } do { status = i2c_do_write(obj, data[count], 0); count++; } while ((count < length) && (status == 0xB8)); if ((status != 0xC0) && (status != 0xC8)) { i2c_stop(obj); } i2c_clear_SI(obj); return(count); } void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) { uint32_t addr; if ((idx >= 0) && (idx <= 3)) { addr = ((uint32_t)obj->i2c) + I2C_addr_offset[0][idx]; *((uint32_t *) addr) = address & 0xFF; addr = ((uint32_t)obj->i2c) + I2C_addr_offset[1][idx]; *((uint32_t *) addr) = mask & 0xFE; } }