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Merge remote-tracking branch 'origin/master' into develop

master
QMK Bot 2021-09-07 15:35:32 +00:00
parent c669c43769 04c0704b28
commit af19461a02
8 changed files with 81 additions and 518 deletions
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82
keyboards/3w6/rev1/matrix.c
View File

@ -35,8 +35,6 @@ extern i2c_status_t tca9555_status;
// | 0 | 1 | 0 | 0 | A2 | A1 | A0 |
// | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
#define I2C_ADDR 0b0100000
#define I2C_ADDR_WRITE ((I2C_ADDR << 1) | I2C_WRITE)
#define I2C_ADDR_READ ((I2C_ADDR << 1) | I2C_READ)
// Register addresses
#define IODIRA 0x06 // i/o direction register
@ -64,19 +62,14 @@ uint8_t init_tca9555(void) {
// - unused : input : 1
// - input : input : 1
// - driving : output : 0
tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_write(IODIRA, I2C_TIMEOUT);
if (tca9555_status) goto out;
// This means: write on pin 5 of port 0, read on rest
tca9555_status = i2c_write(0b11011111, I2C_TIMEOUT);
if (tca9555_status) goto out;
// This means: we will write on pins 0 to 2 on port 1. read rest
tca9555_status = i2c_write(0b11111000, I2C_TIMEOUT);
if (tca9555_status) goto out;
uint8_t conf[2] = {
// This means: write on pin 5 of port 0, read on rest
0b11011111,
// This means: we will write on pins 0 to 2 on port 1. read rest
0b11111000,
};
tca9555_status = i2c_writeReg(I2C_ADDR, IODIRA, conf, 2, I2C_TIMEOUT);
out:
i2c_stop();
return tca9555_status;
}
@ -192,36 +185,29 @@ static matrix_row_t read_cols(uint8_t row) {
if (tca9555_status) { // if there was an error
return 0;
} else {
uint8_t data = 0;
uint8_t port0 = 0;
uint8_t port1 = 0;
tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_write(IREGP0, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_start(I2C_ADDR_READ, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_read_ack(I2C_TIMEOUT);
if (tca9555_status < 0) goto out;
port0 = (uint8_t)tca9555_status;
tca9555_status = i2c_read_nack(I2C_TIMEOUT);
if (tca9555_status < 0) goto out;
port1 = (uint8_t)tca9555_status;
uint8_t data = 0;
uint8_t ports[2] = {0};
tca9555_status = i2c_readReg(I2C_ADDR, IREGP0, ports, 2, I2C_TIMEOUT);
if (tca9555_status) { // if there was an error
// do nothing
return 0;
} else {
uint8_t port0 = ports[0];
uint8_t port1 = ports[1];
// The initial state was all ones and any depressed key at a given column for the currently selected row will have its bit flipped to zero.
// The return value is a row as represented in the generic matrix code were the rightmost bits represent the lower columns and zeroes represent non-depressed keys while ones represent depressed keys.
// Since the pins are not ordered sequentially, we have to build the correct dataset from the two ports. Refer to the schematic to see where every pin is connected.
data |= ( port0 & 0x01 );
data |= ( port0 & 0x02 );
data |= ( port1 & 0x10 ) >> 2;
data |= ( port1 & 0x08 );
data |= ( port0 & 0x40 ) >> 2;
data = ~(data);
// The initial state was all ones and any depressed key at a given column for the currently selected row will have its bit flipped to zero.
// The return value is a row as represented in the generic matrix code were the rightmost bits represent the lower columns and zeroes represent non-depressed keys while ones represent depressed keys.
// Since the pins are not ordered sequentially, we have to build the correct dataset from the two ports. Refer to the schematic to see where every pin is connected.
data |= ( port0 & 0x01 );
data |= ( port0 & 0x02 );
data |= ( port1 & 0x10 ) >> 2;
data |= ( port1 & 0x08 );
data |= ( port0 & 0x40 ) >> 2;
data = ~(data);
tca9555_status = I2C_STATUS_SUCCESS;
out:
i2c_stop();
return data;
tca9555_status = I2C_STATUS_SUCCESS;
return data;
}
}
}
}
@ -263,18 +249,10 @@ static void select_row(uint8_t row) {
default: break;
}
tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_write(OREGP0, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_write(port0, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_write(port1, I2C_TIMEOUT);
if (tca9555_status) goto out;
uint8_t ports[2] = {port0, port1};
tca9555_status = i2c_writeReg(I2C_ADDR, OREGP0, ports, 2, I2C_TIMEOUT);
// Select the desired row by writing a byte for the entire GPIOB bus where only the bit representing the row we want to select is a zero (write instruction) and every other bit is a one.
// Note that the row - MATRIX_ROWS_PER_SIDE reflects the fact that being on the right hand, the columns are numbered from MATRIX_ROWS_PER_SIDE to MATRIX_ROWS, but the pins we want to write to are indexed from zero up on the GPIOB bus.
out:
i2c_stop();
}
}
}

75
keyboards/3w6/rev2/matrix.c
View File

@ -35,8 +35,6 @@ extern i2c_status_t tca9555_status;
// | 0 | 1 | 0 | 0 | A2 | A1 | A0 |
// | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
#define I2C_ADDR 0b0100000
#define I2C_ADDR_WRITE ((I2C_ADDR << 1) | I2C_WRITE)
#define I2C_ADDR_READ ((I2C_ADDR << 1) | I2C_READ)
// Register addresses
#define IODIRA 0x06 // i/o direction register
@ -64,19 +62,14 @@ uint8_t init_tca9555(void) {
// - unused : input : 1
// - input : input : 1
// - driving : output : 0
tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_write(IODIRA, I2C_TIMEOUT);
if (tca9555_status) goto out;
// This means: read all pins of port 0
tca9555_status = i2c_write(0b11111111, I2C_TIMEOUT);
if (tca9555_status) goto out;
// This means: we will write on pins 0 to 3 on port 1. read rest
tca9555_status = i2c_write(0b11110000, I2C_TIMEOUT);
if (tca9555_status) goto out;
uint8_t conf[2] = {
// This means: read all pins of port 0
0b11111111,
// This means: we will write on pins 0 to 3 on port 1. read rest
0b11110000,
};
tca9555_status = i2c_writeReg(I2C_ADDR, IODIRA, conf, 2, I2C_TIMEOUT);
out:
i2c_stop();
return tca9555_status;
}
@ -194,32 +187,27 @@ static matrix_row_t read_cols(uint8_t row) {
} else {
uint8_t data = 0;
uint8_t port0 = 0;
tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_write(IREGP0, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_start(I2C_ADDR_READ, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_read_nack(I2C_TIMEOUT);
if (tca9555_status < 0) goto out;
port0 = ~(uint8_t)tca9555_status;
tca9555_status = i2c_readReg(I2C_ADDR, IREGP0, port0, 1, I2C_TIMEOUT);
if (tca9555_status) { // if there was an error
// do nothing
return 0;
} else {
uint8_t port0 = ports[0];
uint8_t port1 = ports[1];
// We read all the pins on GPIOA.
// The initial state was all ones and any depressed key at a given column for the currently selected row will have its bit flipped to zero.
// The return value is a row as represented in the generic matrix code were the rightmost bits represent the lower columns and zeroes represent non-depressed keys while ones represent depressed keys.
// the pins connected to eact columns are sequential, but in reverse order, and counting from zero down (col 5 -> GPIO04, col6 -> GPIO03 and so on).
data |= ( port0 & 0x01 ) << 4;
data |= ( port0 & 0x02 ) << 2;
data |= ( port0 & 0x04 );
data |= ( port0 & 0x08 ) >> 2;
data |= ( port0 & 0x10 ) >> 4;
// We read all the pins on GPIOA.
// The initial state was all ones and any depressed key at a given column for the currently selected row will have its bit flipped to zero.
// The return value is a row as represented in the generic matrix code were the rightmost bits represent the lower columns and zeroes represent non-depressed keys while ones represent depressed keys.
// the pins connected to eact columns are sequential, but in reverse order, and counting from zero down (col 5 -> GPIO04, col6 -> GPIO03 and so on).
data |= ( port0 & 0x01 ) << 4;
data |= ( port0 & 0x02 ) << 2;
data |= ( port0 & 0x04 );
data |= ( port0 & 0x08 ) >> 2;
data |= ( port0 & 0x10 ) >> 4;
tca9555_status = I2C_STATUS_SUCCESS;
out:
i2c_stop();
return data;
tca9555_status = I2C_STATUS_SUCCESS;
return data;
}
}
}
}
@ -256,20 +244,13 @@ static void select_row(uint8_t row) {
case 4: port1 &= ~(1 << 0); break;
case 5: port1 &= ~(1 << 1); break;
case 6: port1 &= ~(1 << 2); break;
case 7: port1 &= ~(1 << 3); break;
case 7: port0 &= ~(1 << 5); break;
default: break;
}
tca9555_status = i2c_writeReg(I2C_ADDR, OREGP1, port1, 2, I2C_TIMEOUT);
// Select the desired row by writing a byte for the entire GPIOB bus where only the bit representing the row we want to select is a zero (write instruction) and every other bit is a one.
// Note that the row - MATRIX_ROWS_PER_SIDE reflects the fact that being on the right hand, the columns are numbered from MATRIX_ROWS_PER_SIDE to MATRIX_ROWS, but the pins we want to write to are indexed from zero up on the GPIOB bus.
tca9555_status = i2c_start(I2C_ADDR_WRITE, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_write(OREGP1, I2C_TIMEOUT);
if (tca9555_status) goto out;
tca9555_status = i2c_write(port1, I2C_TIMEOUT);
if (tca9555_status) goto out;
out:
i2c_stop();
}
}
}

178
keyboards/sx60/i2cmaster.h
View File

@ -1,178 +0,0 @@
#ifndef _I2CMASTER_H
#define _I2CMASTER_H 1
/*************************************************************************
* Title: C include file for the I2C master interface
* (i2cmaster.S or twimaster.c)
* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
* File: $Id: i2cmaster.h,v 1.10 2005/03/06 22:39:57 Peter Exp $
* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3
* Target: any AVR device
* Usage: see Doxygen manual
**************************************************************************/
#ifdef DOXYGEN
/**
@defgroup pfleury_ic2master I2C Master library
@code #include <i2cmaster.h> @endcode
@brief I2C (TWI) Master Software Library
Basic routines for communicating with I2C slave devices. This single master
implementation is limited to one bus master on the I2C bus.
This I2c library is implemented as a compact assembler software implementation of the I2C protocol
which runs on any AVR (i2cmaster.S) and as a TWI hardware interface for all AVR with built-in TWI hardware (twimaster.c).
Since the API for these two implementations is exactly the same, an application can be linked either against the
software I2C implementation or the hardware I2C implementation.
Use 4.7k pull-up resistor on the SDA and SCL pin.
Adapt the SCL and SDA port and pin definitions and eventually the delay routine in the module
i2cmaster.S to your target when using the software I2C implementation !
Adjust the CPU clock frequence F_CPU in twimaster.c or in the Makfile when using the TWI hardware implementaion.
@note
The module i2cmaster.S is based on the Atmel Application Note AVR300, corrected and adapted
to GNU assembler and AVR-GCC C call interface.
Replaced the incorrect quarter period delays found in AVR300 with
half period delays.
@author Peter Fleury pfleury@gmx.ch http://jump.to/fleury
@par API Usage Example
The following code shows typical usage of this library, see example test_i2cmaster.c
@code
#include <i2cmaster.h>
#define Dev24C02 0xA2 // device address of EEPROM 24C02, see datasheet
int main(void)
{
unsigned char ret;
i2c_init(); // initialize I2C library
// write 0x75 to EEPROM address 5 (Byte Write)
i2c_start_wait(Dev24C02+I2C_WRITE); // set device address and write mode
i2c_write(0x05); // write address = 5
i2c_write(0x75); // write value 0x75 to EEPROM
i2c_stop(); // set stop conditon = release bus
// read previously written value back from EEPROM address 5
i2c_start_wait(Dev24C02+I2C_WRITE); // set device address and write mode
i2c_write(0x05); // write address = 5
i2c_rep_start(Dev24C02+I2C_READ); // set device address and read mode
ret = i2c_readNak(); // read one byte from EEPROM
i2c_stop();
for(;;);
}
@endcode
*/
#endif /* DOXYGEN */
/**@{*/
#if (__GNUC__ * 100 + __GNUC_MINOR__) < 304
#error "This library requires AVR-GCC 3.4 or later, update to newer AVR-GCC compiler !"
#endif
#include <avr/io.h>
/** defines the data direction (reading from I2C device) in i2c_start(),i2c_rep_start() */
#define I2C_READ 1
/** defines the data direction (writing to I2C device) in i2c_start(),i2c_rep_start() */
#define I2C_WRITE 0
/**
@brief initialize the I2C master interace. Need to be called only once
@param void
@return none
*/
extern void i2c_init(void);
/**
@brief Terminates the data transfer and releases the I2C bus
@param void
@return none
*/
extern void i2c_stop(void);
/**
@brief Issues a start condition and sends address and transfer direction
@param addr address and transfer direction of I2C device
@retval 0 device accessible
@retval 1 failed to access device
*/
extern unsigned char i2c_start(unsigned char addr);
/**
@brief Issues a repeated start condition and sends address and transfer direction
@param addr address and transfer direction of I2C device
@retval 0 device accessible
@retval 1 failed to access device
*/
extern unsigned char i2c_rep_start(unsigned char addr);
/**
@brief Issues a start condition and sends address and transfer direction
If device is busy, use ack polling to wait until device ready
@param addr address and transfer direction of I2C device
@return none
*/
extern void i2c_start_wait(unsigned char addr);
/**
@brief Send one byte to I2C device
@param data byte to be transfered
@retval 0 write successful
@retval 1 write failed
*/
extern unsigned char i2c_write(unsigned char data);
/**
@brief read one byte from the I2C device, request more data from device
@return byte read from I2C device
*/
extern unsigned char i2c_readAck(void);
/**
@brief read one byte from the I2C device, read is followed by a stop condition
@return byte read from I2C device
*/
extern unsigned char i2c_readNak(void);
/**
@brief read one byte from the I2C device
Implemented as a macro, which calls either i2c_readAck or i2c_readNak
@param ack 1 send ack, request more data from device<br>
0 send nak, read is followed by a stop condition
@return byte read from I2C device
*/
extern unsigned char i2c_read(unsigned char ack);
#define i2c_read(ack) (ack) ? i2c_readAck() : i2c_readNak();
/**@}*/
#endif

21
keyboards/sx60/matrix.c
View File

@ -243,15 +243,11 @@ static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row)
/* if there was an error */
return 0;
} else {
uint16_t data = 0;
mcp23018_status = i2c_start(I2C_ADDR_WRITE); if (mcp23018_status) goto out;
mcp23018_status = i2c_write(GPIOA); if (mcp23018_status) goto out;
mcp23018_status = i2c_start(I2C_ADDR_READ); if (mcp23018_status) goto out;
data = i2c_readNak();
data = ~data;
out:
i2c_stop();
current_matrix[current_row] |= (data << 8);
uint8_t data = 0;
mcp23018_status = i2c_readReg(I2C_ADDR, GPIOA, &data, 1, I2C_TIMEOUT);
if (!mcp23018_status) {
current_matrix[current_row] |= (~((uint16_t)data) << 8);
}
}
/* For each col... */
@ -278,11 +274,8 @@ static void select_row(uint8_t row)
/* set active row low : 0
set active row output : 1
set other rows hi-Z : 1 */
mcp23018_status = i2c_start(I2C_ADDR_WRITE); if (mcp23018_status) goto out;
mcp23018_status = i2c_write(GPIOB); if (mcp23018_status) goto out;
mcp23018_status = i2c_write(0xFF & ~(1<<abs(row-4))); if (mcp23018_status) goto out;
out:
i2c_stop();
uint8_t port = 0xFF & ~(1<<abs(row-4));
mcp23018_status = i2c_writeReg(I2C_ADDR, GPIOB, &port, 1, I2C_TIMEOUT);
}
uint8_t pin = row_pins[row];

4
keyboards/sx60/rules.mk
View File

@ -27,5 +27,5 @@ RGBLIGHT_ENABLE = no
CUSTOM_MATRIX = yes
# project specific files
SRC = twimaster.c \
matrix.c
QUANTUM_LIB_SRC += i2c_master.c
SRC += matrix.c

27
keyboards/sx60/sx60.c
View File

@ -1,5 +1,5 @@
#include "sx60.h"
#include "i2cmaster.h"
#include "i2c_master.h"
bool i2c_initialized = 0;
@ -18,21 +18,18 @@ uint8_t init_mcp23018(void) {
/* B Pins are Row, A pins are Columns
Set them to output */
mcp23018_status = i2c_start(I2C_ADDR_WRITE); if (mcp23018_status) goto out;
mcp23018_status = i2c_write(IODIRA); if (mcp23018_status) goto out;
mcp23018_status = i2c_write(0b11111111); if (mcp23018_status) goto out;
/* Now write to IODIRB */
mcp23018_status = i2c_write(0b00000000); if (mcp23018_status) goto out;
i2c_stop();
static uint8_t direction[2] = {
0b11111111,
0b00000000,
};
static uint8_t pullup[2] = {
0b11111111,
0b00000000,
};
mcp23018_status = i2c_start(I2C_ADDR_WRITE); if (mcp23018_status) goto out;
mcp23018_status = i2c_write(GPPUA); if (mcp23018_status) goto out;
mcp23018_status = i2c_write(0b11111111); if (mcp23018_status) goto out;
/* Now write to GPPUB */
mcp23018_status = i2c_write(0b00000000); if (mcp23018_status) goto out;
out:
i2c_stop();
mcp23018_status = i2c_writeReg(I2C_ADDR, IODIRA, direction, 2, I2C_TIMEOUT);
if (mcp23018_status) return mcp23018_status;
mcp23018_status = i2c_writeReg(I2C_ADDR, GPPUA, pullup, 2, I2C_TIMEOUT);
return mcp23018_status;
}

5
keyboards/sx60/sx60.h
View File

@ -3,13 +3,12 @@
#include "quantum.h"
#include <stdint.h>
#include <stdbool.h>
#include "i2cmaster.h"
#include "i2c_master.h"
#include <util/delay.h>
/* I2C aliases and register addresses (see "mcp23018.md") */
#define I2C_ADDR 0b0100000
#define I2C_ADDR_WRITE ( (I2C_ADDR<<1) | I2C_WRITE )
#define I2C_ADDR_READ ( (I2C_ADDR<<1) | I2C_READ )
#define I2C_TIMEOUT 100
#define IODIRA 0x00 /* i/o direction register */
#define IODIRB 0x01
#define GPPUA 0x0C /* GPIO pull-up resistor register */

207
keyboards/sx60/twimaster.c
View File

@ -1,207 +0,0 @@
/*************************************************************************
* Title: I2C master library using hardware TWI interface
* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
* File: $Id: twimaster.c,v 1.3 2005/07/02 11:14:21 Peter Exp $
* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3
* Target: any AVR device with hardware TWI
* Usage: API compatible with I2C Software Library i2cmaster.h
**************************************************************************/
#include <inttypes.h>
#include <compat/twi.h>
#include <i2cmaster.h>
/* define CPU frequency in Hz here if not defined in Makefile */
#ifndef F_CPU
#define F_CPU 16000000UL
#endif
/* I2C clock in Hz */
#define SCL_CLOCK 400000L
/*************************************************************************
Initialization of the I2C bus interface. Need to be called only once
*************************************************************************/
void i2c_init(void)
{
/* initialize TWI clock
* minimal values in Bit Rate Register (TWBR) and minimal Prescaler
* bits in the TWI Status Register should give us maximal possible
* I2C bus speed - about 444 kHz
*
* for more details, see 20.5.2 in ATmega16/32 secification
*/
TWSR = 0; /* no prescaler */
TWBR = 10; /* must be >= 10 for stable operation */
}/* i2c_init */
/*************************************************************************
Issues a start condition and sends address and transfer direction.
return 0 = device accessible, 1= failed to access device
*************************************************************************/
unsigned char i2c_start(unsigned char address)
{
uint8_t twst;
/* send START condition */
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
/* wait until transmission completed */
while(!(TWCR & (1<<TWINT)));
/* check value of TWI Status Register. Mask prescaler bits. */
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;
/* send device address */
TWDR = address;
TWCR = (1<<TWINT) | (1<<TWEN);
/* wail until transmission completed and ACK/NACK has been received */
while(!(TWCR & (1<<TWINT)));
/* check value of TWI Status Register. Mask prescaler bits. */
twst = TW_STATUS & 0xF8;
if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;
return 0;
}/* i2c_start */
/*************************************************************************
Issues a start condition and sends address and transfer direction.
If device is busy, use ack polling to wait until device is ready
Input: address and transfer direction of I2C device
*************************************************************************/
void i2c_start_wait(unsigned char address)
{
uint8_t twst;
while ( 1 )
{
/* send START condition */
TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
/* wait until transmission completed */
while(!(TWCR & (1<<TWINT)));
/* check value of TWI Status Register. Mask prescaler bits. */
twst = TW_STATUS & 0xF8;
if ( (twst != TW_START) && (twst != TW_REP_START)) continue;
/* send device address */
TWDR = address;
TWCR = (1<<TWINT) | (1<<TWEN);
/* wail until transmission completed */
while(!(TWCR & (1<<TWINT)));
/* check value of TWI Status Register. Mask prescaler bits. */
twst = TW_STATUS & 0xF8;
if ( (twst == TW_MT_SLA_NACK )||(twst ==TW_MR_DATA_NACK) )
{
/* device busy, send stop condition to terminate write operation */
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
/* wait until stop condition is executed and bus released */
while(TWCR & (1<<TWSTO));
continue;
}
break;
}
}/* i2c_start_wait */
/*************************************************************************
Issues a repeated start condition and sends address and transfer direction
Input: address and transfer direction of I2C device
Return: 0 device accessible
1 failed to access device
*************************************************************************/
unsigned char i2c_rep_start(unsigned char address)
{
return i2c_start( address );
}/* i2c_rep_start */
/*************************************************************************
Terminates the data transfer and releases the I2C bus
*************************************************************************/
void i2c_stop(void)
{
/* send stop condition */
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
/* wait until stop condition is executed and bus released */
while(TWCR & (1<<TWSTO));
}/* i2c_stop */
/*************************************************************************
Send one byte to I2C device
Input: byte to be transfered
Return: 0 write successful
1 write failed
*************************************************************************/
unsigned char i2c_write( unsigned char data )
{
uint8_t twst;
/* send data to the previously addressed device */
TWDR = data;
TWCR = (1<<TWINT) | (1<<TWEN);
/* wait until transmission completed */
while(!(TWCR & (1<<TWINT)));
/* check value of TWI Status Register. Mask prescaler bits */
twst = TW_STATUS & 0xF8;
if( twst != TW_MT_DATA_ACK) return 1;
return 0;
}/* i2c_write */
/*************************************************************************
Read one byte from the I2C device, request more data from device
Return: byte read from I2C device
*************************************************************************/
unsigned char i2c_readAck(void)
{
TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
while(!(TWCR & (1<<TWINT)));
return TWDR;
}/* i2c_readAck */
/*************************************************************************
Read one byte from the I2C device, read is followed by a stop condition
Return: byte read from I2C device
*************************************************************************/
unsigned char i2c_readNak(void)
{
TWCR = (1<<TWINT) | (1<<TWEN);
while(!(TWCR & (1<<TWINT)));
return TWDR;
}/* i2c_readNak */