handwired/dactyl - Refactor use of legacy i2c implementation (#14344)
Joel Challis
4 years ago
committed by
GitHub
parent
04c0704b28
commit
60c5bd7b5e
@ -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 |
||||
@ -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; |
||||
} |
||||
//if( twst != TW_MT_SLA_ACK) return 1;
|
||||
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 */ |
||||
Loading…
Reference in new issue