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Diffstat (limited to 'keyboard/ergodox/twimaster.c')
| -rw-r--r-- | keyboard/ergodox/twimaster.c | 208 |
1 files changed, 0 insertions, 208 deletions
diff --git a/keyboard/ergodox/twimaster.c b/keyboard/ergodox/twimaster.c deleted file mode 100644 index f91c08e6e4..0000000000 --- a/keyboard/ergodox/twimaster.c +++ /dev/null @@ -1,208 +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 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 */ |