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Update I2C library

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This commit is contained in:
Mark Sikora 2017-04-23 20:12:22 -04:00
parent f7b0c6f1fc
commit 79159729cd
2 changed files with 18 additions and 24 deletions
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20
keyboard/ergodox/i2cmaster.h
View file

@ -1,17 +1,17 @@
#ifndef _I2CMASTER_H #ifndef _I2CMASTER_H
#define _I2CMASTER_H 1 #define _I2CMASTER_H
/************************************************************************* /*************************************************************************
* Title: C include file for the I2C master interface * Title: C include file for the I2C master interface
* (i2cmaster.S or twimaster.c) * (i2cmaster.S or twimaster.c)
* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury * Author: Peter Fleury <pfleury@gmx.ch>
* File: $Id: i2cmaster.h,v 1.10 2005/03/06 22:39:57 Peter Exp $ * File: $Id: i2cmaster.h,v 1.12 2015/09/16 09:27:58 peter Exp $
* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3 * Software: AVR-GCC 4.x
* Target: any AVR device * Target: any AVR device
* Usage: see Doxygen manual * Usage: see Doxygen manual
**************************************************************************/ **************************************************************************/
#ifdef DOXYGEN
/** /**
@file
@defgroup pfleury_ic2master I2C Master library @defgroup pfleury_ic2master I2C Master library
@code #include <i2cmaster.h> @endcode @code #include <i2cmaster.h> @endcode
@ -38,7 +38,8 @@
Replaced the incorrect quarter period delays found in AVR300 with Replaced the incorrect quarter period delays found in AVR300 with
half period delays. half period delays.
@author Peter Fleury pfleury@gmx.ch http://jump.to/fleury @author Peter Fleury pfleury@gmx.ch http://tinyurl.com/peterfleury
@copyright (C) 2015 Peter Fleury, GNU General Public License Version 3
@par API Usage Example @par API Usage Example
The following code shows typical usage of this library, see example test_i2cmaster.c The following code shows typical usage of this library, see example test_i2cmaster.c
@ -77,7 +78,7 @@
@endcode @endcode
*/ */
#endif /* DOXYGEN */
/**@{*/ /**@{*/
@ -96,7 +97,6 @@
/** /**
@brief initialize the I2C master interace. Need to be called only once @brief initialize the I2C master interace. Need to be called only once
@param void
@return none @return none
*/ */
extern void i2c_init(void); extern void i2c_init(void);
@ -104,7 +104,6 @@ extern void i2c_init(void);
/** /**
@brief Terminates the data transfer and releases the I2C bus @brief Terminates the data transfer and releases the I2C bus
@param void
@return none @return none
*/ */
extern void i2c_stop(void); extern void i2c_stop(void);
@ -164,7 +163,7 @@ extern unsigned char i2c_readNak(void);
/** /**
@brief read one byte from the I2C device @brief read one byte from the I2C device
Implemented as a macro, which calls either i2c_readAck or i2c_readNak Implemented as a macro, which calls either @ref i2c_readAck or @ref i2c_readNak
@param ack 1 send ack, request more data from device<br> @param ack 1 send ack, request more data from device<br>
0 send nak, read is followed by a stop condition 0 send nak, read is followed by a stop condition
@ -174,5 +173,6 @@ extern unsigned char i2c_read(unsigned char ack);
#define i2c_read(ack) (ack) ? i2c_readAck() : i2c_readNak(); #define i2c_read(ack) (ack) ? i2c_readAck() : i2c_readNak();
/**@}*/ /**@}*/
#endif #endif

18
keyboard/ergodox/twimaster.c
View file

@ -1,7 +1,7 @@
/************************************************************************* /*************************************************************************
* Title: I2C master library using hardware TWI interface * Title: I2C master library using hardware TWI interface
* Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury * 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 $ * File: $Id: twimaster.c,v 1.4 2015/01/17 12:16:05 peter Exp $
* Software: AVR-GCC 3.4.3 / avr-libc 1.2.3 * Software: AVR-GCC 3.4.3 / avr-libc 1.2.3
* Target: any AVR device with hardware TWI * Target: any AVR device with hardware TWI
* Usage: API compatible with I2C Software Library i2cmaster.h * Usage: API compatible with I2C Software Library i2cmaster.h
@ -12,13 +12,13 @@
#include <i2cmaster.h> #include <i2cmaster.h>
/* define CPU frequency in Mhz here if not defined in Makefile */ /* define CPU frequency in hz here if not defined in Makefile */
#ifndef F_CPU #ifndef F_CPU
#define F_CPU 16000000UL #define F_CPU 4000000UL
#endif #endif
/* I2C clock in Hz */ /* I2C clock in Hz */
#define SCL_CLOCK 400000L #define SCL_CLOCK 100000L
/************************************************************************* /*************************************************************************
@ -26,16 +26,10 @@
*************************************************************************/ *************************************************************************/
void i2c_init(void) void i2c_init(void)
{ {
/* initialize TWI clock /* initialize TWI clock: 100 kHz clock, TWPS = 0 => prescaler = 1 */
* 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 */ TWSR = 0; /* no prescaler */
TWBR = 10; /* must be >= 10 for stable operation */ TWBR = ((F_CPU/SCL_CLOCK)-16)/2; /* must be > 10 for stable operation */
}/* i2c_init */ }/* i2c_init */