mirror of https://github.com/ARMmbed/mbed-os.git
423 lines
11 KiB
C
423 lines
11 KiB
C
/* mbed Microcontroller Library
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* Copyright (c) 2006-2013 ARM Limited
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "mbed_assert.h"
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#include "i2c_api.h"
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#include "cmsis.h"
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#include "pinmap.h"
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static const PinMap PinMap_I2C_SDA[] = {
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{P0_0 , I2C_1, 3},
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{P0_10, I2C_2, 2},
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{P0_19, I2C_1, 3},
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{P0_27, I2C_0, 1},
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{P1_15, I2C_2, 3},
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{P1_30, I2C_0, 4},
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{P2_14, I2C_1, 2},
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{P2_30, I2C_2, 2},
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{P4_20, I2C_2, 4},
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{P5_2, I2C_0, 5},
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{NC , NC , 0}
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};
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static const PinMap PinMap_I2C_SCL[] = {
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{P0_1 , I2C_1, 3},
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{P0_11, I2C_2, 2},
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{P0_20, I2C_1, 3},
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{P0_28, I2C_0, 1},
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{P1_31, I2C_0, 4},
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{P2_15, I2C_1, 2},
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{P2_31, I2C_2, 2},
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{P4_21, I2C_2, 2},
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{P4_29, I2C_2, 4},
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{P5_3, I2C_0, 5},
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{NC , NC, 0}
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};
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#define I2C_CONSET(x) (x->i2c->CONSET)
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#define I2C_CONCLR(x) (x->i2c->CONCLR)
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#define I2C_STAT(x) (x->i2c->STAT)
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#define I2C_DAT(x) (x->i2c->DAT)
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#define I2C_SCLL(x, val) (x->i2c->SCLL = val)
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#define I2C_SCLH(x, val) (x->i2c->SCLH = val)
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static const uint32_t I2C_addr_offset[2][4] = {
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{0x0C, 0x20, 0x24, 0x28},
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{0x30, 0x34, 0x38, 0x3C}
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};
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static inline void i2c_conclr(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) {
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I2C_CONCLR(obj) = (start << 5)
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| (stop << 4)
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| (interrupt << 3)
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| (acknowledge << 2);
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}
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static inline void i2c_conset(i2c_t *obj, int start, int stop, int interrupt, int acknowledge) {
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I2C_CONSET(obj) = (start << 5)
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| (stop << 4)
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| (interrupt << 3)
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| (acknowledge << 2);
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}
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// Clear the Serial Interrupt (SI)
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static inline void i2c_clear_SI(i2c_t *obj) {
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i2c_conclr(obj, 0, 0, 1, 0);
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}
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static inline int i2c_status(i2c_t *obj) {
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return I2C_STAT(obj);
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}
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// Wait until the Serial Interrupt (SI) is set
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static int i2c_wait_SI(i2c_t *obj) {
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int timeout = 0;
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while (!(I2C_CONSET(obj) & (1 << 3))) {
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timeout++;
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if (timeout > 100000) return -1;
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}
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return 0;
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}
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static inline void i2c_interface_enable(i2c_t *obj) {
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I2C_CONSET(obj) = 0x40;
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}
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static inline void i2c_power_enable(i2c_t *obj) {
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switch ((int)obj->i2c) {
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case I2C_0: LPC_SC->PCONP |= 1 << 7; break;
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case I2C_1: LPC_SC->PCONP |= 1 << 19; break;
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case I2C_2: LPC_SC->PCONP |= 1 << 26; break;
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}
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}
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void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
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// determine the SPI to use
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I2CName i2c_sda = (I2CName)pinmap_peripheral(sda, PinMap_I2C_SDA);
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I2CName i2c_scl = (I2CName)pinmap_peripheral(scl, PinMap_I2C_SCL);
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obj->i2c = (LPC_I2C_TypeDef *)pinmap_merge(i2c_sda, i2c_scl);
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MBED_ASSERT((int)obj->i2c != NC);
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// enable power
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i2c_power_enable(obj);
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// set default frequency at 100k
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i2c_frequency(obj, 100000);
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i2c_conclr(obj, 1, 1, 1, 1);
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i2c_interface_enable(obj);
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pinmap_pinout(sda, PinMap_I2C_SDA);
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pinmap_pinout(scl, PinMap_I2C_SCL);
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// OpenDrain must explicitly be enabled for p0.0 and p0.1
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if (sda == P0_0) {
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pin_mode(sda, OpenDrain);
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}
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if (scl == P0_1) {
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pin_mode(scl, OpenDrain);
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}
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}
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inline int i2c_start(i2c_t *obj) {
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int status = 0;
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int isInterrupted = I2C_CONSET(obj) & (1 << 3);
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// 8.1 Before master mode can be entered, I2CON must be initialised to:
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// - I2EN STA STO SI AA - -
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// - 1 0 0 x x - -
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// if AA = 0, it can't enter slave mode
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i2c_conclr(obj, 1, 1, 0, 1);
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// The master mode may now be entered by setting the STA bit
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// this will generate a start condition when the bus becomes free
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i2c_conset(obj, 1, 0, 0, 1);
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// Clearing SI bit when it wasn't set on entry can jump past state
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// 0x10 or 0x08 and erroneously send uninitialized slave address.
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if (isInterrupted)
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i2c_clear_SI(obj);
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i2c_wait_SI(obj);
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status = i2c_status(obj);
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// Clear start bit now that it's transmitted
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i2c_conclr(obj, 1, 0, 0, 0);
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return status;
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}
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inline int i2c_stop(i2c_t *obj) {
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int timeout = 0;
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// write the stop bit
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i2c_conset(obj, 0, 1, 0, 0);
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i2c_clear_SI(obj);
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// wait for STO bit to reset
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while(I2C_CONSET(obj) & (1 << 4)) {
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timeout ++;
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if (timeout > 100000) return 1;
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}
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return 0;
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}
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static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) {
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// write the data
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I2C_DAT(obj) = value;
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// clear SI to init a send
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i2c_clear_SI(obj);
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// wait and return status
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i2c_wait_SI(obj);
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return i2c_status(obj);
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}
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static inline int i2c_do_read(i2c_t *obj, int last) {
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// we are in state 0x40 (SLA+R tx'd) or 0x50 (data rx'd and ack)
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if(last) {
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i2c_conclr(obj, 0, 0, 0, 1); // send a NOT ACK
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} else {
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i2c_conset(obj, 0, 0, 0, 1); // send a ACK
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}
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// accept byte
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i2c_clear_SI(obj);
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// wait for it to arrive
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i2c_wait_SI(obj);
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// return the data
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return (I2C_DAT(obj) & 0xFF);
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}
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void i2c_frequency(i2c_t *obj, int hz) {
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uint32_t PCLK = PeripheralClock;
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uint32_t pulse = PCLK / (hz * 2);
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// I2C Rate
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I2C_SCLL(obj, pulse);
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I2C_SCLH(obj, pulse);
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}
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// The I2C does a read or a write as a whole operation
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// There are two types of error conditions it can encounter
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// 1) it can not obtain the bus
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// 2) it gets error responses at part of the transmission
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//
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// We tackle them as follows:
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// 1) we retry until we get the bus. we could have a "timeout" if we can not get it
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// which basically turns it in to a 2)
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// 2) on error, we use the standard error mechanisms to report/debug
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//
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// Therefore an I2C transaction should always complete. If it doesn't it is usually
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// because something is setup wrong (e.g. wiring), and we don't need to programatically
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// check for that
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int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
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int count, status;
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status = i2c_start(obj);
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if ((status != 0x10) && (status != 0x08)) {
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i2c_stop(obj);
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return I2C_ERROR_BUS_BUSY;
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}
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status = i2c_do_write(obj, (address | 0x01), 1);
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if (status != 0x40) {
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i2c_stop(obj);
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return I2C_ERROR_NO_SLAVE;
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}
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// Read in all except last byte
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for (count = 0; count < (length - 1); count++) {
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int value = i2c_do_read(obj, 0);
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status = i2c_status(obj);
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if (status != 0x50) {
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i2c_stop(obj);
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return count;
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}
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data[count] = (char) value;
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}
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// read in last byte
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int value = i2c_do_read(obj, 1);
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status = i2c_status(obj);
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if (status != 0x58) {
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i2c_stop(obj);
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return length - 1;
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}
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data[count] = (char) value;
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// If not repeated start, send stop.
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if (stop) {
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i2c_stop(obj);
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}
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return length;
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}
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int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
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int i, status;
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status = i2c_start(obj);
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if ((status != 0x10) && (status != 0x08)) {
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i2c_stop(obj);
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return I2C_ERROR_BUS_BUSY;
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}
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status = i2c_do_write(obj, (address & 0xFE), 1);
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if (status != 0x18) {
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i2c_stop(obj);
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return I2C_ERROR_NO_SLAVE;
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}
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for (i=0; i<length; i++) {
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status = i2c_do_write(obj, data[i], 0);
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if (status != 0x28) {
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i2c_stop(obj);
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return i;
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}
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}
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// clearing the serial interrupt here might cause an unintended rewrite of the last byte
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// see also issue report https://mbed.org/users/mbed_official/code/mbed/issues/1
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// i2c_clear_SI(obj);
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// If not repeated start, send stop.
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if (stop) {
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i2c_stop(obj);
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}
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return length;
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}
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void i2c_reset(i2c_t *obj) {
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i2c_stop(obj);
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}
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int i2c_byte_read(i2c_t *obj, int last) {
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return (i2c_do_read(obj, last) & 0xFF);
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}
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int i2c_byte_write(i2c_t *obj, int data) {
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int ack;
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int status = i2c_do_write(obj, (data & 0xFF), 0);
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switch(status) {
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case 0x18: case 0x28: // Master transmit ACKs
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ack = 1;
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break;
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case 0x40: // Master receive address transmitted ACK
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ack = 1;
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break;
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case 0xB8: // Slave transmit ACK
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ack = 1;
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break;
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default:
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ack = 0;
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break;
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}
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return ack;
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}
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void i2c_slave_mode(i2c_t *obj, int enable_slave) {
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if (enable_slave != 0) {
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i2c_conclr(obj, 1, 1, 1, 0);
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i2c_conset(obj, 0, 0, 0, 1);
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} else {
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i2c_conclr(obj, 1, 1, 1, 1);
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}
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}
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int i2c_slave_receive(i2c_t *obj) {
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int status;
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int retval;
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status = i2c_status(obj);
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switch(status) {
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case 0x60: retval = 3; break;
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case 0x70: retval = 2; break;
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case 0xA8: retval = 1; break;
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default : retval = 0; break;
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}
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return(retval);
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}
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int i2c_slave_read(i2c_t *obj, char *data, int length) {
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int count = 0;
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int status;
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do {
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i2c_clear_SI(obj);
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i2c_wait_SI(obj);
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status = i2c_status(obj);
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if((status == 0x80) || (status == 0x90)) {
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data[count] = I2C_DAT(obj) & 0xFF;
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}
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count++;
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} while (((status == 0x80) || (status == 0x90) ||
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(status == 0x060) || (status == 0x70)) && (count < length));
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if(status != 0xA0) {
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i2c_stop(obj);
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}
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i2c_clear_SI(obj);
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return count;
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}
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int i2c_slave_write(i2c_t *obj, const char *data, int length) {
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int count = 0;
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int status;
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if(length <= 0) {
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return(0);
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}
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do {
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status = i2c_do_write(obj, data[count], 0);
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count++;
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} while ((count < length) && (status == 0xB8));
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if((status != 0xC0) && (status != 0xC8)) {
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i2c_stop(obj);
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}
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i2c_clear_SI(obj);
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return(count);
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}
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void i2c_slave_address(i2c_t *obj, int idx, uint32_t address, uint32_t mask) {
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uint32_t addr;
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if ((idx >= 0) && (idx <= 3)) {
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addr = ((uint32_t)obj->i2c) + I2C_addr_offset[0][idx];
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*((uint32_t *) addr) = address & 0xFF;
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addr = ((uint32_t)obj->i2c) + I2C_addr_offset[1][idx];
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*((uint32_t *) addr) = mask & 0xFE;
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}
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}
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