From: Mark Sikora <marknsikora@gmail.com>
Date: Mon, 24 Apr 2017 00:12:22 +0000 (-0400)
Subject: Update I2C library
X-Git-Url: https://git.friedersdorff.com/?a=commitdiff_plain;h=79159729cd621b97e3e1de2478f45697f242a661;p=max%2Ftmk_keyboard.git

Update I2C library
---

diff --git a/keyboard/ergodox/i2cmaster.h b/keyboard/ergodox/i2cmaster.h
index 3917b9e6..8e5d1462 100644
--- a/keyboard/ergodox/i2cmaster.h
+++ b/keyboard/ergodox/i2cmaster.h
@@ -1,17 +1,17 @@
 #ifndef _I2CMASTER_H
-#define _I2CMASTER_H   1
+#define _I2CMASTER_H
 /************************************************************************* 
 * 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
+* Author:   Peter Fleury <pfleury@gmx.ch>
+* File:     $Id: i2cmaster.h,v 1.12 2015/09/16 09:27:58 peter Exp $
+* Software: AVR-GCC 4.x
 * Target:   any AVR device
 * Usage:    see Doxygen manual
 **************************************************************************/
 
-#ifdef DOXYGEN
 /**
+ @file
  @defgroup pfleury_ic2master I2C Master library
  @code #include <i2cmaster.h> @endcode
   
@@ -38,8 +38,9 @@
     Replaced the incorrect quarter period delays found in AVR300 with 
     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
   The following code shows typical usage of this library, see example test_i2cmaster.c
 
@@ -77,7 +78,7 @@
  @endcode
 
 */
-#endif /* DOXYGEN */
+
 
 /**@{*/
 
@@ -96,7 +97,6 @@
 
 /**
  @brief initialize the I2C master interace. Need to be called only once 
- @param  void
  @return none
  */
 extern void i2c_init(void);
@@ -104,7 +104,6 @@ extern void i2c_init(void);
 
 /** 
  @brief Terminates the data transfer and releases the I2C bus 
- @param void
  @return none
  */
 extern void i2c_stop(void);
@@ -164,7 +163,7 @@ 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
+ 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>
                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(); 
 
 
+
 /**@}*/
 #endif
diff --git a/keyboard/ergodox/twimaster.c b/keyboard/ergodox/twimaster.c
index f91c08e6..3f9ccb3c 100644
--- a/keyboard/ergodox/twimaster.c
+++ b/keyboard/ergodox/twimaster.c
@@ -1,7 +1,7 @@
 /*************************************************************************
 * 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 $
+* 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
 * Target:   any AVR device with hardware TWI 
 * Usage:    API compatible with I2C Software Library i2cmaster.h
@@ -12,13 +12,13 @@
 #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
-#define F_CPU 16000000UL
+#define F_CPU 4000000UL
 #endif
 
 /* I2C clock in Hz */
-#define SCL_CLOCK  400000L
+#define SCL_CLOCK  100000L
 
 
 /*************************************************************************
@@ -26,16 +26,10 @@
 *************************************************************************/
 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
-   */
+  /* initialize TWI clock: 100 kHz clock, TWPS = 0 => prescaler = 1 */
   
-  TWSR = 0;     /* no prescaler */
-  TWBR = 10;    /* must be >= 10 for stable operation */
+  TWSR = 0;                         /* no prescaler */
+  TWBR = ((F_CPU/SCL_CLOCK)-16)/2;  /* must be > 10 for stable operation */
 
 }/* i2c_init */