From 35a81f5b8b081e1607a7c04489b01f551c3213cc Mon Sep 17 00:00:00 2001 From: Jack Humbert Date: Mon, 26 Oct 2015 16:32:37 -0400 Subject: added ergodox --- keyboard/ergodox/twimaster.c | 208 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 208 insertions(+) create mode 100644 keyboard/ergodox/twimaster.c (limited to 'keyboard/ergodox/twimaster.c') diff --git a/keyboard/ergodox/twimaster.c b/keyboard/ergodox/twimaster.c new file mode 100644 index 0000000000..f91c08e6e4 --- /dev/null +++ b/keyboard/ergodox/twimaster.c @@ -0,0 +1,208 @@ +/************************************************************************* +* Title: I2C master library using hardware TWI interface +* Author: Peter Fleury 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 +#include + +#include + + +/* 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<