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Initial Arduino IDE based on Processing.
This commit is contained in:
David A. Mellis
635
build/shared/lib/avrlib/i2c.c
Executable file
635
build/shared/lib/avrlib/i2c.c
Executable file
@ -0,0 +1,635 @@
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/*! \file i2c.c \brief I2C interface using AVR Two-Wire Interface (TWI) hardware. */
|
||||
//*****************************************************************************
|
||||
//
|
||||
// File Name : 'i2c.c'
|
||||
// Title : I2C interface using AVR Two-Wire Interface (TWI) hardware
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||||
// Author : Pascal Stang - Copyright (C) 2002-2003
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// Created : 2002.06.25
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// Revised : 2003.03.02
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||||
// Version : 0.9
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||||
// Target MCU : Atmel AVR series
|
||||
// Editor Tabs : 4
|
||||
//
|
||||
// Description : I2C (pronounced "eye-squared-see") is a two-wire bidirectional
|
||||
// network designed for easy transfer of information between a wide variety
|
||||
// of intelligent devices. Many of the Atmel AVR series processors have
|
||||
// hardware support for transmitting and receiving using an I2C-type bus.
|
||||
// In addition to the AVRs, there are thousands of other parts made by
|
||||
// manufacturers like Philips, Maxim, National, TI, etc that use I2C as
|
||||
// their primary means of communication and control. Common device types
|
||||
// are A/D & D/A converters, temp sensors, intelligent battery monitors,
|
||||
// MP3 decoder chips, EEPROM chips, multiplexing switches, etc.
|
||||
//
|
||||
// I2C uses only two wires (SDA and SCL) to communicate bidirectionally
|
||||
// between devices. I2C is a multidrop network, meaning that you can have
|
||||
// several devices on a single bus. Because I2C uses a 7-bit number to
|
||||
// identify which device it wants to talk to, you cannot have more than
|
||||
// 127 devices on a single bus.
|
||||
//
|
||||
// I2C ordinarily requires two 4.7K pull-up resistors to power (one each on
|
||||
// SDA and SCL), but for small numbers of devices (maybe 1-4), it is enough
|
||||
// to activate the internal pull-up resistors in the AVR processor. To do
|
||||
// this, set the port pins, which correspond to the I2C pins SDA/SCL, high.
|
||||
// For example, on the mega163, sbi(PORTC, 0); sbi(PORTC, 1);.
|
||||
//
|
||||
// For complete information about I2C, see the Philips Semiconductor
|
||||
// website. They created I2C and have the largest family of devices that
|
||||
// work with I2C.
|
||||
//
|
||||
// Note: Many manufacturers market I2C bus devices under a different or generic
|
||||
// bus name like "Two-Wire Interface". This is because Philips still holds
|
||||
// "I2C" as a trademark. For example, SMBus and SMBus devices are hardware
|
||||
// compatible and closely related to I2C. They can be directly connected
|
||||
// to an I2C bus along with other I2C devices are are generally accessed in
|
||||
// the same way as I2C devices. SMBus is often found on modern motherboards
|
||||
// for temp sensing and other low-level control tasks.
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||||
//
|
||||
// This code is distributed under the GNU Public License
|
||||
// which can be found at http://www.gnu.org/licenses/gpl.txt
|
||||
//
|
||||
//*****************************************************************************
|
||||
|
||||
#include <avr/io.h>
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#include <avr/signal.h>
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||||
#include <avr/interrupt.h>
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||||
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||||
#include "i2c.h"
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||||
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||||
#include "rprintf.h" // include printf function library
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#include "uart2.h"
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||||
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||||
// Standard I2C bit rates are:
|
||||
// 100KHz for slow speed
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// 400KHz for high speed
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||||
|
||||
//#define I2C_DEBUG
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||||
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||||
// I2C state and address variables
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static volatile eI2cStateType I2cState;
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static u08 I2cDeviceAddrRW;
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// send/transmit buffer (outgoing data)
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static u08 I2cSendData[I2C_SEND_DATA_BUFFER_SIZE];
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static u08 I2cSendDataIndex;
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||||
static u08 I2cSendDataLength;
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// receive buffer (incoming data)
|
||||
static u08 I2cReceiveData[I2C_RECEIVE_DATA_BUFFER_SIZE];
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||||
static u08 I2cReceiveDataIndex;
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static u08 I2cReceiveDataLength;
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// function pointer to i2c receive routine
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||||
//! I2cSlaveReceive is called when this processor
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||||
// is addressed as a slave for writing
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||||
static void (*i2cSlaveReceive)(u08 receiveDataLength, u08* recieveData);
|
||||
//! I2cSlaveTransmit is called when this processor
|
||||
// is addressed as a slave for reading
|
||||
static u08 (*i2cSlaveTransmit)(u08 transmitDataLengthMax, u08* transmitData);
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||||
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// functions
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||||
void i2cInit(void)
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||||
{
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||||
// set pull-up resistors on I2C bus pins
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// TODO: should #ifdef these
|
||||
sbi(PORTC, 0); // i2c SCL on ATmega163,323,16,32,etc
|
||||
sbi(PORTC, 1); // i2c SDA on ATmega163,323,16,32,etc
|
||||
sbi(PORTD, 0); // i2c SCL on ATmega128,64
|
||||
sbi(PORTD, 1); // i2c SDA on ATmega128,64
|
||||
|
||||
// clear SlaveReceive and SlaveTransmit handler to null
|
||||
i2cSlaveReceive = 0;
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||||
i2cSlaveTransmit = 0;
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||||
// set i2c bit rate to 100KHz
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||||
i2cSetBitrate(100);
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||||
// enable TWI (two-wire interface)
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||||
sbi(TWCR, TWEN);
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||||
// set state
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||||
I2cState = I2C_IDLE;
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||||
// enable TWI interrupt and slave address ACK
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||||
sbi(TWCR, TWIE);
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||||
sbi(TWCR, TWEA);
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||||
//outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWEA));
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||||
// enable interrupts
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||||
sei();
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}
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||||
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||||
void i2cSetBitrate(u16 bitrateKHz)
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||||
{
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||||
u08 bitrate_div;
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// set i2c bitrate
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||||
// SCL freq = F_CPU/(16+2*TWBR))
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||||
#ifdef TWPS0
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||||
// for processors with additional bitrate division (mega128)
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||||
// SCL freq = F_CPU/(16+2*TWBR*4^TWPS)
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||||
// set TWPS to zero
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||||
cbi(TWSR, TWPS0);
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||||
cbi(TWSR, TWPS1);
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||||
#endif
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||||
// calculate bitrate division
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bitrate_div = ((F_CPU/1000l)/bitrateKHz);
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if(bitrate_div >= 16)
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bitrate_div = (bitrate_div-16)/2;
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||||
outb(TWBR, bitrate_div);
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}
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||||
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void i2cSetLocalDeviceAddr(u08 deviceAddr, u08 genCallEn)
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||||
{
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// set local device address (used in slave mode only)
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outb(TWAR, ((deviceAddr&0xFE) | (genCallEn?1:0)) );
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||||
}
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||||
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||||
void i2cSetSlaveReceiveHandler(void (*i2cSlaveRx_func)(u08 receiveDataLength, u08* recieveData))
|
||||
{
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||||
i2cSlaveReceive = i2cSlaveRx_func;
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||||
}
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||||
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||||
void i2cSetSlaveTransmitHandler(u08 (*i2cSlaveTx_func)(u08 transmitDataLengthMax, u08* transmitData))
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||||
{
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||||
i2cSlaveTransmit = i2cSlaveTx_func;
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||||
}
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||||
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||||
inline void i2cSendStart(void)
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||||
{
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||||
// send start condition
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||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWSTA));
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||||
}
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||||
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||||
inline void i2cSendStop(void)
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||||
{
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||||
// transmit stop condition
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||||
// leave with TWEA on for slave receiving
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||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWEA)|BV(TWSTO));
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||||
}
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||||
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||||
inline void i2cWaitForComplete(void)
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||||
{
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||||
// wait for i2c interface to complete operation
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||||
while( !(inb(TWCR) & BV(TWINT)) );
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||||
}
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||||
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||||
inline void i2cSendByte(u08 data)
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||||
{
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||||
// save data to the TWDR
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||||
outb(TWDR, data);
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||||
// begin send
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||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT));
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||||
}
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||||
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||||
inline void i2cReceiveByte(u08 ackFlag)
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||||
{
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// begin receive over i2c
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||||
if( ackFlag )
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||||
{
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||||
// ackFlag = TRUE: ACK the recevied data
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||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWEA));
|
||||
}
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||||
else
|
||||
{
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||||
// ackFlag = FALSE: NACK the recevied data
|
||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT));
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||||
}
|
||||
}
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||||
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||||
inline u08 i2cGetReceivedByte(void)
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||||
{
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||||
// retieve received data byte from i2c TWDR
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||||
return( inb(TWDR) );
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||||
}
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||||
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||||
inline u08 i2cGetStatus(void)
|
||||
{
|
||||
// retieve current i2c status from i2c TWSR
|
||||
return( inb(TWSR) );
|
||||
}
|
||||
|
||||
void i2cMasterSend(u08 deviceAddr, u08 length, u08* data)
|
||||
{
|
||||
u08 i;
|
||||
// wait for interface to be ready
|
||||
while(I2cState);
|
||||
// set state
|
||||
I2cState = I2C_MASTER_TX;
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||||
// save data
|
||||
I2cDeviceAddrRW = (deviceAddr & 0xFE); // RW cleared: write operation
|
||||
for(i=0; i<length; i++)
|
||||
I2cSendData[i] = *data++;
|
||||
I2cSendDataIndex = 0;
|
||||
I2cSendDataLength = length;
|
||||
// send start condition
|
||||
i2cSendStart();
|
||||
}
|
||||
|
||||
void i2cMasterReceive(u08 deviceAddr, u08 length, u08* data)
|
||||
{
|
||||
u08 i;
|
||||
// wait for interface to be ready
|
||||
while(I2cState);
|
||||
// set state
|
||||
I2cState = I2C_MASTER_RX;
|
||||
// save data
|
||||
I2cDeviceAddrRW = (deviceAddr|0x01); // RW set: read operation
|
||||
I2cReceiveDataIndex = 0;
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||||
I2cReceiveDataLength = length;
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||||
// send start condition
|
||||
i2cSendStart();
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||||
// wait for data
|
||||
while(I2cState);
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||||
// return data
|
||||
for(i=0; i<length; i++)
|
||||
*data++ = I2cReceiveData[i];
|
||||
}
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||||
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||||
u08 i2cMasterSendNI(u08 deviceAddr, u08 length, u08* data)
|
||||
{
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||||
u08 retval = I2C_OK;
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||||
|
||||
// disable TWI interrupt
|
||||
cbi(TWCR, TWIE);
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||||
|
||||
// send start condition
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||||
i2cSendStart();
|
||||
i2cWaitForComplete();
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||||
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||||
// send device address with write
|
||||
i2cSendByte( deviceAddr & 0xFE );
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||||
i2cWaitForComplete();
|
||||
|
||||
// check if device is present and live
|
||||
if( inb(TWSR) == TW_MT_SLA_ACK)
|
||||
{
|
||||
// send data
|
||||
while(length)
|
||||
{
|
||||
i2cSendByte( *data++ );
|
||||
i2cWaitForComplete();
|
||||
length--;
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
// device did not ACK it's address,
|
||||
// data will not be transferred
|
||||
// return error
|
||||
retval = I2C_ERROR_NODEV;
|
||||
}
|
||||
|
||||
// transmit stop condition
|
||||
// leave with TWEA on for slave receiving
|
||||
i2cSendStop();
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||||
while( !(inb(TWCR) & BV(TWSTO)) );
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||||
|
||||
// enable TWI interrupt
|
||||
sbi(TWCR, TWIE);
|
||||
|
||||
return retval;
|
||||
}
|
||||
|
||||
u08 i2cMasterReceiveNI(u08 deviceAddr, u08 length, u08 *data)
|
||||
{
|
||||
u08 retval = I2C_OK;
|
||||
|
||||
// disable TWI interrupt
|
||||
cbi(TWCR, TWIE);
|
||||
|
||||
// send start condition
|
||||
i2cSendStart();
|
||||
i2cWaitForComplete();
|
||||
|
||||
// send device address with read
|
||||
i2cSendByte( deviceAddr | 0x01 );
|
||||
i2cWaitForComplete();
|
||||
|
||||
// check if device is present and live
|
||||
if( inb(TWSR) == TW_MR_SLA_ACK)
|
||||
{
|
||||
// accept receive data and ack it
|
||||
while(length > 1)
|
||||
{
|
||||
i2cReceiveByte(TRUE);
|
||||
i2cWaitForComplete();
|
||||
*data++ = i2cGetReceivedByte();
|
||||
// decrement length
|
||||
length--;
|
||||
}
|
||||
|
||||
// accept receive data and nack it (last-byte signal)
|
||||
i2cReceiveByte(FALSE);
|
||||
i2cWaitForComplete();
|
||||
*data++ = i2cGetReceivedByte();
|
||||
}
|
||||
else
|
||||
{
|
||||
// device did not ACK it's address,
|
||||
// data will not be transferred
|
||||
// return error
|
||||
retval = I2C_ERROR_NODEV;
|
||||
}
|
||||
|
||||
// transmit stop condition
|
||||
// leave with TWEA on for slave receiving
|
||||
i2cSendStop();
|
||||
|
||||
// enable TWI interrupt
|
||||
sbi(TWCR, TWIE);
|
||||
|
||||
return retval;
|
||||
}
|
||||
/*
|
||||
void i2cMasterTransferNI(u08 deviceAddr, u08 sendlength, u08* senddata, u08 receivelength, u08* receivedata)
|
||||
{
|
||||
// disable TWI interrupt
|
||||
cbi(TWCR, TWIE);
|
||||
|
||||
// send start condition
|
||||
i2cSendStart();
|
||||
i2cWaitForComplete();
|
||||
|
||||
// if there's data to be sent, do it
|
||||
if(sendlength)
|
||||
{
|
||||
// send device address with write
|
||||
i2cSendByte( deviceAddr & 0xFE );
|
||||
i2cWaitForComplete();
|
||||
|
||||
// send data
|
||||
while(sendlength)
|
||||
{
|
||||
i2cSendByte( *senddata++ );
|
||||
i2cWaitForComplete();
|
||||
sendlength--;
|
||||
}
|
||||
}
|
||||
|
||||
// if there's data to be received, do it
|
||||
if(receivelength)
|
||||
{
|
||||
// send repeated start condition
|
||||
i2cSendStart();
|
||||
i2cWaitForComplete();
|
||||
|
||||
// send device address with read
|
||||
i2cSendByte( deviceAddr | 0x01 );
|
||||
i2cWaitForComplete();
|
||||
|
||||
// accept receive data and ack it
|
||||
while(receivelength > 1)
|
||||
{
|
||||
i2cReceiveByte(TRUE);
|
||||
i2cWaitForComplete();
|
||||
*receivedata++ = i2cGetReceivedByte();
|
||||
// decrement length
|
||||
receivelength--;
|
||||
}
|
||||
|
||||
// accept receive data and nack it (last-byte signal)
|
||||
i2cReceiveByte(TRUE);
|
||||
i2cWaitForComplete();
|
||||
*receivedata++ = i2cGetReceivedByte();
|
||||
}
|
||||
|
||||
// transmit stop condition
|
||||
// leave with TWEA on for slave receiving
|
||||
i2cSendStop();
|
||||
while( !(inb(TWCR) & BV(TWSTO)) );
|
||||
|
||||
// enable TWI interrupt
|
||||
sbi(TWCR, TWIE);
|
||||
}
|
||||
*/
|
||||
|
||||
//! I2C (TWI) interrupt service routine
|
||||
SIGNAL(SIG_2WIRE_SERIAL)
|
||||
{
|
||||
// read status bits
|
||||
u08 status = inb(TWSR) & TWSR_STATUS_MASK;
|
||||
|
||||
switch(status)
|
||||
{
|
||||
// Master General
|
||||
case TW_START: // 0x08: Sent start condition
|
||||
case TW_REP_START: // 0x10: Sent repeated start condition
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: M->START\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// send device address
|
||||
i2cSendByte(I2cDeviceAddrRW);
|
||||
break;
|
||||
|
||||
// Master Transmitter & Receiver status codes
|
||||
case TW_MT_SLA_ACK: // 0x18: Slave address acknowledged
|
||||
case TW_MT_DATA_ACK: // 0x28: Data acknowledged
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: MT->SLA_ACK or DATA_ACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
if(I2cSendDataIndex < I2cSendDataLength)
|
||||
{
|
||||
// send data
|
||||
i2cSendByte( I2cSendData[I2cSendDataIndex++] );
|
||||
}
|
||||
else
|
||||
{
|
||||
// transmit stop condition, enable SLA ACK
|
||||
i2cSendStop();
|
||||
// set state
|
||||
I2cState = I2C_IDLE;
|
||||
}
|
||||
break;
|
||||
case TW_MR_DATA_NACK: // 0x58: Data received, NACK reply issued
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: MR->DATA_NACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// store final received data byte
|
||||
I2cReceiveData[I2cReceiveDataIndex++] = inb(TWDR);
|
||||
// continue to transmit STOP condition
|
||||
case TW_MR_SLA_NACK: // 0x48: Slave address not acknowledged
|
||||
case TW_MT_SLA_NACK: // 0x20: Slave address not acknowledged
|
||||
case TW_MT_DATA_NACK: // 0x30: Data not acknowledged
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: MTR->SLA_NACK or MT->DATA_NACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// transmit stop condition, enable SLA ACK
|
||||
i2cSendStop();
|
||||
// set state
|
||||
I2cState = I2C_IDLE;
|
||||
break;
|
||||
case TW_MT_ARB_LOST: // 0x38: Bus arbitration lost
|
||||
//case TW_MR_ARB_LOST: // 0x38: Bus arbitration lost
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: MT->ARB_LOST\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// release bus
|
||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT));
|
||||
// set state
|
||||
I2cState = I2C_IDLE;
|
||||
// release bus and transmit start when bus is free
|
||||
//outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWSTA));
|
||||
break;
|
||||
case TW_MR_DATA_ACK: // 0x50: Data acknowledged
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: MR->DATA_ACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// store received data byte
|
||||
I2cReceiveData[I2cReceiveDataIndex++] = inb(TWDR);
|
||||
// fall-through to see if more bytes will be received
|
||||
case TW_MR_SLA_ACK: // 0x40: Slave address acknowledged
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: MR->SLA_ACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
if(I2cReceiveDataIndex < (I2cReceiveDataLength-1))
|
||||
// data byte will be received, reply with ACK (more bytes in transfer)
|
||||
i2cReceiveByte(TRUE);
|
||||
else
|
||||
// data byte will be received, reply with NACK (final byte in transfer)
|
||||
i2cReceiveByte(FALSE);
|
||||
break;
|
||||
|
||||
// Slave Receiver status codes
|
||||
case TW_SR_SLA_ACK: // 0x60: own SLA+W has been received, ACK has been returned
|
||||
case TW_SR_ARB_LOST_SLA_ACK: // 0x68: own SLA+W has been received, ACK has been returned
|
||||
case TW_SR_GCALL_ACK: // 0x70: GCA+W has been received, ACK has been returned
|
||||
case TW_SR_ARB_LOST_GCALL_ACK: // 0x78: GCA+W has been received, ACK has been returned
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: SR->SLA_ACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// we are being addressed as slave for writing (data will be received from master)
|
||||
// set state
|
||||
I2cState = I2C_SLAVE_RX;
|
||||
// prepare buffer
|
||||
I2cReceiveDataIndex = 0;
|
||||
// receive data byte and return ACK
|
||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWEA));
|
||||
break;
|
||||
case TW_SR_DATA_ACK: // 0x80: data byte has been received, ACK has been returned
|
||||
case TW_SR_GCALL_DATA_ACK: // 0x90: data byte has been received, ACK has been returned
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: SR->DATA_ACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// get previously received data byte
|
||||
I2cReceiveData[I2cReceiveDataIndex++] = inb(TWDR);
|
||||
// check receive buffer status
|
||||
if(I2cReceiveDataIndex < I2C_RECEIVE_DATA_BUFFER_SIZE)
|
||||
{
|
||||
// receive data byte and return ACK
|
||||
i2cReceiveByte(TRUE);
|
||||
//outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWEA));
|
||||
}
|
||||
else
|
||||
{
|
||||
// receive data byte and return NACK
|
||||
i2cReceiveByte(FALSE);
|
||||
//outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT));
|
||||
}
|
||||
break;
|
||||
case TW_SR_DATA_NACK: // 0x88: data byte has been received, NACK has been returned
|
||||
case TW_SR_GCALL_DATA_NACK: // 0x98: data byte has been received, NACK has been returned
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: SR->DATA_NACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// receive data byte and return NACK
|
||||
i2cReceiveByte(FALSE);
|
||||
//outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT));
|
||||
break;
|
||||
case TW_SR_STOP: // 0xA0: STOP or REPEATED START has been received while addressed as slave
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: SR->SR_STOP\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// switch to SR mode with SLA ACK
|
||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWEA));
|
||||
// i2c receive is complete, call i2cSlaveReceive
|
||||
if(i2cSlaveReceive) i2cSlaveReceive(I2cReceiveDataIndex, I2cReceiveData);
|
||||
// set state
|
||||
I2cState = I2C_IDLE;
|
||||
break;
|
||||
|
||||
// Slave Transmitter
|
||||
case TW_ST_SLA_ACK: // 0xA8: own SLA+R has been received, ACK has been returned
|
||||
case TW_ST_ARB_LOST_SLA_ACK: // 0xB0: GCA+R has been received, ACK has been returned
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: ST->SLA_ACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// we are being addressed as slave for reading (data must be transmitted back to master)
|
||||
// set state
|
||||
I2cState = I2C_SLAVE_TX;
|
||||
// request data from application
|
||||
if(i2cSlaveTransmit) I2cSendDataLength = i2cSlaveTransmit(I2C_SEND_DATA_BUFFER_SIZE, I2cSendData);
|
||||
// reset data index
|
||||
I2cSendDataIndex = 0;
|
||||
// fall-through to transmit first data byte
|
||||
case TW_ST_DATA_ACK: // 0xB8: data byte has been transmitted, ACK has been received
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: ST->DATA_ACK\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// transmit data byte
|
||||
outb(TWDR, I2cSendData[I2cSendDataIndex++]);
|
||||
if(I2cSendDataIndex < I2cSendDataLength)
|
||||
// expect ACK to data byte
|
||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWEA));
|
||||
else
|
||||
// expect NACK to data byte
|
||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT));
|
||||
break;
|
||||
case TW_ST_DATA_NACK: // 0xC0: data byte has been transmitted, NACK has been received
|
||||
case TW_ST_LAST_DATA: // 0xC8:
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: ST->DATA_NACK or LAST_DATA\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// all done
|
||||
// switch to open slave
|
||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWEA));
|
||||
// set state
|
||||
I2cState = I2C_IDLE;
|
||||
break;
|
||||
|
||||
// Misc
|
||||
case TW_NO_INFO: // 0xF8: No relevant state information
|
||||
// do nothing
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: NO_INFO\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
break;
|
||||
case TW_BUS_ERROR: // 0x00: Bus error due to illegal start or stop condition
|
||||
#ifdef I2C_DEBUG
|
||||
rprintfInit(uart1AddToTxBuffer);
|
||||
rprintf("I2C: BUS_ERROR\r\n");
|
||||
rprintfInit(uart1SendByte);
|
||||
#endif
|
||||
// reset internal hardware and release bus
|
||||
outb(TWCR, (inb(TWCR)&TWCR_CMD_MASK)|BV(TWINT)|BV(TWSTO)|BV(TWEA));
|
||||
// set state
|
||||
I2cState = I2C_IDLE;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
eI2cStateType i2cGetState(void)
|
||||
{
|
||||
return I2cState;
|
||||
}
|
||||
Reference in New Issue
Block a user