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authorRyan Ascheman <rascheman@groupon.com>2016-10-18 12:42:02 -0700
committerRyan Ascheman <rascheman@groupon.com>2016-10-18 12:42:02 -0700
commit55b8b8477cc6aee82dfe6792eea4e589cac433d5 (patch)
treece5bfbd1b0ee59dbffdc2044bcf90c89614392ed /keyboards/ergodox/ez/twimaster.c
parentd1c70328f8d8ded6ce1e5422b468fc41ef315e7d (diff)
parent04df74f6360464661bcc1e6794e9fd3549084390 (diff)
Merge remote-tracking branch 'upstream/master'
* upstream/master: (1239 commits) Update ez.c removes planck/rev3 temporarily Move hand_swap_config to ez.c, removes error for infinity Update Makefile ergodox: Update algernon's keymap to v1.9 Added VS Code dir to .gitignore Support the Pegasus Hoof controller. [Jack & Erez] Simplifies and documents TO add readme use wait_ms instead of _delay_ms add messenger init keymap Add example keymap Adding whiskey_tango_foxtrot_capslock ergodox keymap Unicode map framework. Allow unicode up to 0xFFFFF using separate mapping table CIE 1931 dim curve Apply the dim curve to the RGB output Update the Cluecard readme files Tune snake and knight intervals for Cluecard Tunable RGB light intervals ...
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+/*************************************************************************
+* 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 */