Seeed / eMPL_MPU

motion library for mpu6050, mpu9250 and etc, supports i2c and spi

mbed_i2c.c@0:814475fdc553, 2016-07-05 (annotated)

Committer:
yihui
Date:
Tue Jul 05 07:19:59 2016 +0000
Revision:
0:814475fdc553
initial

Who changed what in which revision?

UserRevisionLine numberNew contents of line
yihui 0:814475fdc553 1
yihui 0:814475fdc553 2 #include <stdio.h>
yihui 0:814475fdc553 3 #include "i2c_api.h"
yihui 0:814475fdc553 4 #include "gpio_api.h"
yihui 0:814475fdc553 5 #include "wait_api.h"
yihui 0:814475fdc553 6
yihui 0:814475fdc553 7 #ifdef TARGET_MCU_NRF51822
yihui 0:814475fdc553 8 #include "nrf51.h"
yihui 0:814475fdc553 9 static PinName mbed_i2c_sda_pin = NC;
yihui 0:814475fdc553 10 static PinName mbed_i2c_scl_pin = NC;
yihui 0:814475fdc553 11 static uint32_t mbed_i2c_sda_cnf;
yihui 0:814475fdc553 12 static uint32_t mbed_i2c_scl_cnf;
yihui 0:814475fdc553 13 #endif
yihui 0:814475fdc553 14
yihui 0:814475fdc553 15 static i2c_t mbed_i2c_object = {0,};
yihui 0:814475fdc553 16
yihui 0:814475fdc553 17
yihui 0:814475fdc553 18 void mbed_i2c_init(PinName sda, PinName scl)
yihui 0:814475fdc553 19 {
yihui 0:814475fdc553 20
yihui 0:814475fdc553 21 mbed_i2c_sda_pin = sda;
yihui 0:814475fdc553 22 mbed_i2c_scl_pin = scl;
yihui 0:814475fdc553 23
yihui 0:814475fdc553 24 i2c_init(&mbed_i2c_object, sda, scl);
yihui 0:814475fdc553 25 i2c_frequency(&mbed_i2c_object, 100000);
yihui 0:814475fdc553 26 }
yihui 0:814475fdc553 27
yihui 0:814475fdc553 28 int mbed_i2c_write(unsigned char slave_addr,
yihui 0:814475fdc553 29 unsigned char reg_addr,
yihui 0:814475fdc553 30 unsigned char length,
yihui 0:814475fdc553 31 unsigned char const *data)
yihui 0:814475fdc553 32 {
yihui 0:814475fdc553 33 int i;
yihui 0:814475fdc553 34 slave_addr = slave_addr << 1;
yihui 0:814475fdc553 35 i2c_start(&mbed_i2c_object);
yihui 0:814475fdc553 36 i2c_byte_write(&mbed_i2c_object, slave_addr);
yihui 0:814475fdc553 37 i2c_byte_write(&mbed_i2c_object, reg_addr);
yihui 0:814475fdc553 38 for (i = 0; i < length; i++) {
yihui 0:814475fdc553 39 i2c_byte_write(&mbed_i2c_object, data[i]);
yihui 0:814475fdc553 40 }
yihui 0:814475fdc553 41 i2c_stop(&mbed_i2c_object);
yihui 0:814475fdc553 42 return 0;
yihui 0:814475fdc553 43 }
yihui 0:814475fdc553 44
yihui 0:814475fdc553 45 int mbed_i2c_read(unsigned char slave_addr,
yihui 0:814475fdc553 46 unsigned char reg_addr,
yihui 0:814475fdc553 47 unsigned char length,
yihui 0:814475fdc553 48 unsigned char *data)
yihui 0:814475fdc553 49 {
yihui 0:814475fdc553 50 slave_addr = slave_addr << 1;
yihui 0:814475fdc553 51 i2c_write(&mbed_i2c_object, slave_addr, &reg_addr, 1, 0);
yihui 0:814475fdc553 52 return (i2c_read(&mbed_i2c_object, slave_addr, data, length, 1) == length) ? 0 : 1;
yihui 0:814475fdc553 53 }
yihui 0:814475fdc553 54
yihui 0:814475fdc553 55 int mbed_i2c_clear(PinName sda, PinName scl)
yihui 0:814475fdc553 56 {
yihui 0:814475fdc553 57 gpio_t sda_io, scl_io;
yihui 0:814475fdc553 58
yihui 0:814475fdc553 59 #ifdef TARGET_MCU_NRF51822
yihui 0:814475fdc553 60 uint32_t sda_cnf = NRF_GPIO->PIN_CNF[sda];
yihui 0:814475fdc553 61 uint32_t scl_cnf = NRF_GPIO->PIN_CNF[scl];
yihui 0:814475fdc553 62 if (mbed_i2c_object.i2c) {
yihui 0:814475fdc553 63 mbed_i2c_object.i2c->PSELSCL = 0xFFFFFFFF;
yihui 0:814475fdc553 64 mbed_i2c_object.i2c->PSELSDA = 0xFFFFFFFF;
yihui 0:814475fdc553 65 }
yihui 0:814475fdc553 66 #endif
yihui 0:814475fdc553 67
yihui 0:814475fdc553 68 gpio_init_in(&sda_io, sda);
yihui 0:814475fdc553 69
yihui 0:814475fdc553 70 if (!gpio_read(&sda_io)) {
yihui 0:814475fdc553 71 printf("sda is always 0, i2c bus is not released\r\n");
yihui 0:814475fdc553 72 printf("try to clear i2c bus\r\n");
yihui 0:814475fdc553 73 gpio_init_out(&scl_io, scl);
yihui 0:814475fdc553 74
yihui 0:814475fdc553 75 // Clock max 18 pulses worst case scenario(9 for master to send the rest of command and 9
yihui 0:814475fdc553 76 // for slave to respond) to SCL line and wait for SDA come high.
yihui 0:814475fdc553 77 for (int i = 0; i < 18; i++) {
yihui 0:814475fdc553 78 gpio_write(&scl_io, 0);
yihui 0:814475fdc553 79 wait_us(4);
yihui 0:814475fdc553 80 gpio_write(&scl_io, 1);
yihui 0:814475fdc553 81 wait_us(4);
yihui 0:814475fdc553 82 }
yihui 0:814475fdc553 83
yihui 0:814475fdc553 84 if (!gpio_read(&sda_io)) {
yihui 0:814475fdc553 85 printf("warning! sda is still 0,, i2c bus is not released\r\n");
yihui 0:814475fdc553 86 }
yihui 0:814475fdc553 87 }
yihui 0:814475fdc553 88
yihui 0:814475fdc553 89 #ifdef TARGET_MCU_NRF51822
yihui 0:814475fdc553 90 NRF_GPIO->PIN_CNF[sda] = sda_cnf;
yihui 0:814475fdc553 91 NRF_GPIO->PIN_CNF[scl] = scl_cnf;
yihui 0:814475fdc553 92 if (mbed_i2c_object.i2c) {
yihui 0:814475fdc553 93 mbed_i2c_object.i2c->PSELSCL = scl;
yihui 0:814475fdc553 94 mbed_i2c_object.i2c->PSELSDA = sda;
yihui 0:814475fdc553 95 }
yihui 0:814475fdc553 96 #endif
yihui 0:814475fdc553 97
yihui 0:814475fdc553 98 return 0;
yihui 0:814475fdc553 99 }
yihui 0:814475fdc553 100
yihui 0:814475fdc553 101 void mbed_i2c_enable(void)
yihui 0:814475fdc553 102 {
yihui 0:814475fdc553 103 #ifdef TARGET_MCU_NRF51822
yihui 0:814475fdc553 104 NRF_GPIO->PIN_CNF[mbed_i2c_sda_pin] = mbed_i2c_sda_cnf;
yihui 0:814475fdc553 105 NRF_GPIO->PIN_CNF[mbed_i2c_scl_pin] = mbed_i2c_scl_cnf;
yihui 0:814475fdc553 106
yihui 0:814475fdc553 107 mbed_i2c_object.i2c->ENABLE = 4;
yihui 0:814475fdc553 108 #endif
yihui 0:814475fdc553 109 }
yihui 0:814475fdc553 110
yihui 0:814475fdc553 111 void mbed_i2c_disable(void)
yihui 0:814475fdc553 112 {
yihui 0:814475fdc553 113 #ifdef TARGET_MCU_NRF51822
yihui 0:814475fdc553 114 mbed_i2c_sda_cnf = NRF_GPIO->PIN_CNF[mbed_i2c_sda_pin];
yihui 0:814475fdc553 115 mbed_i2c_scl_cnf = NRF_GPIO->PIN_CNF[mbed_i2c_scl_pin];
yihui 0:814475fdc553 116
yihui 0:814475fdc553 117 mbed_i2c_object.i2c->ENABLE = 0;
yihui 0:814475fdc553 118
yihui 0:814475fdc553 119 NRF_GPIO->PIN_CNF[mbed_i2c_sda_pin] = 2;
yihui 0:814475fdc553 120 NRF_GPIO->PIN_CNF[mbed_i2c_scl_pin] = 2;
yihui 0:814475fdc553 121 #endif
yihui 0:814475fdc553 122 }