X-Git-Url: https://git.friedersdorff.com/?a=blobdiff_plain;f=keyboard%2Fergodox%2Ftwimaster.c;h=f91c08e6e4e83ccd0fc570848d82845a43b0c9f5;hb=d2427380e3d82df0f9b543615c27f9d823a09306;hp=f0d850c25710efb1ee67269d2f9edfb261fedc96;hpb=cfc23836e5f9571056d3710b8580c1f27b91ed54;p=max%2Ftmk_keyboard.git

diff --git a/keyboard/ergodox/twimaster.c b/keyboard/ergodox/twimaster.c
index f0d850c2..f91c08e6 100644
--- a/keyboard/ergodox/twimaster.c
+++ b/keyboard/ergodox/twimaster.c
@@ -1,202 +1,208 @@
-/*************************************************************************
-* 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 Mhz here if not defined in Makefile */
-#ifndef F_CPU
-#define F_CPU 4000000UL
-#endif
-
-/* I2C clock in Hz */
-#define SCL_CLOCK  100000L
-
-
-/*************************************************************************
- Initialization of the I2C bus interface. Need to be called only once
-*************************************************************************/
-void i2c_init(void)
-{
-  /* initialize TWI clock: 100 kHz clock, TWPS = 0 => prescaler = 1 */
-  
-  TWSR = 0;                         /* no prescaler */
-  TWBR = ((F_CPU/SCL_CLOCK)-16)/2;  /* 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 */
+/*************************************************************************
+* 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 Mhz 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 */