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Added BMP180 and I2C driver and example

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Fixed reference to unknown environment var
Moved drivers into extras folder and added additional documentations.
Changed LOCAL to static and renamed DEBUG to BMP180_DEBUG
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Angus71 2015-08-25 14:45:48 +02:00
parent 22d35ed5f2
commit fd1081a0cc
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extras/i2c/LICENSE Normal file
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The MIT License (MIT)
Copyright (c) 2015 Johan Kanflo
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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# Yet another I2C driver for the ESP8266
This time a driver for the excellent esp-open-rtos. This is a bit banging I2C driver based on the Wikipedia pesudo C code [1].
### Adding to your project
Add the driver to your project as a submodule rather than cloning it:
````
% git submodule add https://github.com/kanflo/esp-open-rtos-driver-i2c.git i2c
````
The esp-open-rtos makefile-fu will make sure the driver is built.
### Usage
````
#include <i2c.h>
#define SCL_PIN (0)
#define SDA_PIN (2)
uint8_t slave_addr = 0x20;
uint8_t reg_addr = 0x1f;
uint8_t reg_data;
uint8_t data[] = {reg_addr, 0xc8};
i2c_init(SCL_PIN, SDA_PIN);
// Write data to slave
bool success = i2c_slave_write(slave_addr, data, sizeof(data));
// Issue write to slave, sending reg_addr, followed by reading 1 byte
success = i2c_slave_read(slave_addr, &reg_addr, reg_data, 1);
````
The driver is released under the MIT license.
[1] https://en.wikipedia.org/wiki/I²C#Example_of_bit-banging_the_I.C2.B2C_Master_protocol

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# Component makefile for extras/i2c
INC_DIRS += $(ROOT)extras
# args for passing into compile rule generation
extras/i2c_INC_DIR = $(ROOT)extras
extras/i2c_SRC_DIR = $(ROOT)extras/i2c
$(eval $(call component_compile_rules,extras/i2c))

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extras/i2c/i2c.c Normal file
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/*
* The MIT License (MIT)
*
* Copyright (c) 2015 Johan Kanflo (github.com/kanflo)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <esp8266.h>
#include <espressif/esp_misc.h> // sdk_os_delay_us
#include "i2c.h"
// I2C driver for ESP8266 written for use with esp-open-rtos
// Based on https://en.wikipedia.org/wiki/I²C#Example_of_bit-banging_the_I.C2.B2C_Master_protocol
// With calling overhead, we end up at ~100kbit/s
#define CLK_HALF_PERIOD_US (1)
#define CLK_STRETCH (10)
static bool started;
static uint8_t g_scl_pin;
static uint8_t g_sda_pin;
void i2c_init(uint8_t scl_pin, uint8_t sda_pin)
{
started = false;
g_scl_pin = scl_pin;
g_sda_pin = sda_pin;
}
static void i2c_delay(void)
{
sdk_os_delay_us(CLK_HALF_PERIOD_US);
}
// Set SCL as input and return current level of line, 0 or 1
static bool read_scl(void)
{
gpio_enable(g_scl_pin, GPIO_INPUT);
return gpio_read(g_scl_pin); // Clock high, valid ACK
}
// Set SDA as input and return current level of line, 0 or 1
static bool read_sda(void)
{
gpio_enable(g_sda_pin, GPIO_INPUT);
// TODO: Without this delay we get arbitration lost in i2c_stop
i2c_delay();
return gpio_read(g_sda_pin); // Clock high, valid ACK
}
// Actively drive SCL signal low
static void clear_scl(void)
{
gpio_enable(g_scl_pin, GPIO_OUTPUT);
gpio_write(g_scl_pin, 0);
}
// Actively drive SDA signal low
static void clear_sda(void)
{
gpio_enable(g_sda_pin, GPIO_OUTPUT);
gpio_write(g_sda_pin, 0);
}
// Output start condition
void i2c_start(void)
{
uint32_t clk_stretch = CLK_STRETCH;
if (started) { // if started, do a restart cond
// Set SDA to 1
(void) read_sda();
i2c_delay();
while (read_scl() == 0 && clk_stretch--) ;
// Repeated start setup time, minimum 4.7us
i2c_delay();
}
if (read_sda() == 0) {
printf("I2C: arbitration lost in i2c_start\n");
}
// SCL is high, set SDA from 1 to 0.
clear_sda();
i2c_delay();
clear_scl();
started = true;
}
// Output stop condition
void i2c_stop(void)
{
uint32_t clk_stretch = CLK_STRETCH;
// Set SDA to 0
clear_sda();
i2c_delay();
// Clock stretching
while (read_scl() == 0 && clk_stretch--) ;
// Stop bit setup time, minimum 4us
i2c_delay();
// SCL is high, set SDA from 0 to 1
if (read_sda() == 0) {
printf("I2C: arbitration lost in i2c_stop\n");
}
i2c_delay();
started = false;
}
// Write a bit to I2C bus
static void i2c_write_bit(bool bit)
{
uint32_t clk_stretch = CLK_STRETCH;
if (bit) {
(void) read_sda();
} else {
clear_sda();
}
i2c_delay();
// Clock stretching
while (read_scl() == 0 && clk_stretch--) ;
// SCL is high, now data is valid
// If SDA is high, check that nobody else is driving SDA
if (bit && read_sda() == 0) {
printf("I2C: arbitration lost in i2c_write_bit\n");
}
i2c_delay();
clear_scl();
}
// Read a bit from I2C bus
static bool i2c_read_bit(void)
{
uint32_t clk_stretch = CLK_STRETCH;
bool bit;
// Let the slave drive data
(void) read_sda();
i2c_delay();
// Clock stretching
while (read_scl() == 0 && clk_stretch--) ;
// SCL is high, now data is valid
bit = read_sda();
i2c_delay();
clear_scl();
return bit;
}
bool i2c_write(uint8_t byte)
{
bool nack;
uint8_t bit;
for (bit = 0; bit < 8; bit++) {
i2c_write_bit((byte & 0x80) != 0);
byte <<= 1;
}
nack = i2c_read_bit();
return !nack;
}
uint8_t i2c_read(bool ack)
{
uint8_t byte = 0;
uint8_t bit;
for (bit = 0; bit < 8; bit++) {
byte = (byte << 1) | i2c_read_bit();
}
i2c_write_bit(ack);
return byte;
}
bool i2c_slave_write(uint8_t slave_addr, uint8_t *data, uint8_t len)
{
bool success = false;
do {
i2c_start();
if (!i2c_write(slave_addr << 1))
break;
while (len--) {
if (!i2c_write(*data++))
break;
}
i2c_stop();
success = true;
} while(0);
return success;
}
bool i2c_slave_read(uint8_t slave_addr, uint8_t data, uint8_t *buf, uint32_t len)
{
bool success = false;
do {
i2c_start();
if (!i2c_write(slave_addr << 1)) {
break;
}
i2c_write(data);
i2c_stop();
i2c_start();
if (!i2c_write(slave_addr << 1 | 1)) { // Slave address + read
break;
}
while(len) {
*buf = i2c_read(len == 1);
buf++;
len--;
}
success = true;
} while(0);
i2c_stop();
if (!success) {
printf("I2C: write error\n");
}
return success;
}

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/*
* The MIT License (MIT)
*
* Copyright (c) 2015 Johan Kanflo (github.com/kanflo)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef __I2C_H__
#define __I2C_H__
#endif
#include <stdint.h>
#include <stdbool.h>
// Init bitbanging I2C driver on given pins
void i2c_init(uint8_t scl_pin, uint8_t sda_pin);
// Write a byte to I2C bus. Return true if slave acked.
bool i2c_write(uint8_t byte);
// Read a byte from I2C bus. Return true if slave acked.
uint8_t i2c_read(bool ack);
// Write 'len' bytes from 'buf' to slave. Return true if slave acked.
bool i2c_slave_write(uint8_t slave_addr, uint8_t *buf, uint8_t len);
// Issue a read operation and send 'data', followed by reading 'len' bytes
// from slave into 'buf'. Return true if slave acked.
bool i2c_slave_read(uint8_t slave_addr, uint8_t data, uint8_t *buf, uint32_t len);
// Send start and stop conditions. Only needed when implementing protocols for
// devices where the i2c_slave_[read|write] functions above are of no use.
void i2c_start(void);
void i2c_stop(void);