mbed library sources modified for open wear
Dependents: openwear-lifelogger-example
Fork of mbed-src by
Diff: targets/hal/TARGET_NXP/TARGET_LPC176X/i2c_api.c
- Revision:
- 13:0645d8841f51
- Child:
- 227:7bd0639b8911
diff -r 5fa2273de5db -r 0645d8841f51 targets/hal/TARGET_NXP/TARGET_LPC176X/i2c_api.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_NXP/TARGET_LPC176X/i2c_api.c Mon Aug 05 14:12:34 2013 +0300 @@ -0,0 +1,397 @@ +/* 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; + } +}