Include initial implementation based on Arduino's twi
This commit is contained in:
Yuri D'Elia
parent
502bc8c72d
commit
240dc1132e
@ -31,8 +31,8 @@
|
||||
|
||||
//PAT9125 configuration
|
||||
//#define PAT9125_SWSPI
|
||||
#define PAT9125_SWI2C
|
||||
//#define PAT9125_I2C
|
||||
//#define PAT9125_SWI2C
|
||||
#define PAT9125_I2C
|
||||
|
||||
#define PAT9125_I2C_ADDR 0x75 //ID=LO
|
||||
//#define PAT9125_I2C_ADDR 0x79 //ID=HI
|
||||
|
||||
@ -31,7 +31,7 @@
|
||||
#elif defined(PAT9125_SWI2C)
|
||||
#include "swi2c.h"
|
||||
#elif defined(PAT9125_I2C)
|
||||
#error not implemented
|
||||
#include "twi.h"
|
||||
#else
|
||||
#error unknown PAT9125 communication method
|
||||
#endif
|
||||
@ -253,39 +253,48 @@ uint8_t pat9125_update_bs(void)
|
||||
uint8_t pat9125_rd_reg(uint8_t addr)
|
||||
{
|
||||
uint8_t data = 0;
|
||||
#ifdef PAT9125_SWSPI
|
||||
#if defined(PAT9125_SWSPI)
|
||||
swspi_start();
|
||||
swspi_tx(addr & 0x7f);
|
||||
data = swspi_rx();
|
||||
swspi_stop();
|
||||
#endif //PAT9125_SWSPI
|
||||
#ifdef PAT9125_SWI2C
|
||||
#elif defined(PAT9125_SWI2C)
|
||||
if (!swi2c_readByte_A8(PAT9125_I2C_ADDR, addr, &data)) //NO ACK error
|
||||
{
|
||||
pat9125_PID1 = 0xff;
|
||||
pat9125_PID2 = 0xff;
|
||||
return 0;
|
||||
}
|
||||
#endif //PAT9125_SWI2C
|
||||
goto error;
|
||||
#elif defined(PAT9125_I2C)
|
||||
if (twi_writeTo(PAT9125_I2C_ADDR,&addr,1,1,0) != 0 ||
|
||||
twi_readFrom(PAT9125_I2C_ADDR,&data,1,1) != 1)
|
||||
goto error;
|
||||
#endif
|
||||
return data;
|
||||
|
||||
error:
|
||||
pat9125_PID1 = 0xff;
|
||||
pat9125_PID2 = 0xff;
|
||||
return 0;
|
||||
}
|
||||
|
||||
void pat9125_wr_reg(uint8_t addr, uint8_t data)
|
||||
{
|
||||
#ifdef PAT9125_SWSPI
|
||||
#if defined(PAT9125_SWSPI)
|
||||
swspi_start();
|
||||
swspi_tx(addr | 0x80);
|
||||
swspi_tx(data);
|
||||
swspi_stop();
|
||||
#endif //PAT9125_SWSPI
|
||||
#ifdef PAT9125_SWI2C
|
||||
#elif defined(PAT9125_SWI2C)
|
||||
if (!swi2c_writeByte_A8(PAT9125_I2C_ADDR, addr, &data)) //NO ACK error
|
||||
{
|
||||
pat9125_PID1 = 0xff;
|
||||
pat9125_PID2 = 0xff;
|
||||
return;
|
||||
}
|
||||
#endif //PAT9125_SWI2C
|
||||
goto error;
|
||||
#elif defined(PAT9125_I2C)
|
||||
if (twi_writeTo(PAT9125_I2C_ADDR,&addr,1,1,0) != 0 ||
|
||||
twi_writeTo(PAT9125_I2C_ADDR,&data,1,1,1) != 0)
|
||||
goto error;
|
||||
#endif
|
||||
return;
|
||||
|
||||
error:
|
||||
pat9125_PID1 = 0xff;
|
||||
pat9125_PID2 = 0xff;
|
||||
return;
|
||||
}
|
||||
|
||||
uint8_t pat9125_wr_reg_verify(uint8_t addr, uint8_t data)
|
||||
|
||||
561
Firmware/twi.c
Normal file
561
Firmware/twi.c
Normal file
@ -0,0 +1,561 @@
|
||||
/*
|
||||
twi.c - TWI/I2C library for Wiring & Arduino
|
||||
Copyright (c) 2006 Nicholas Zambetti. All right reserved.
|
||||
|
||||
This library is free software; you can redistribute it and/or
|
||||
modify it under the terms of the GNU Lesser General Public
|
||||
License as published by the Free Software Foundation; either
|
||||
version 2.1 of the License, or (at your option) any later version.
|
||||
|
||||
This library is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
Lesser General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU Lesser General Public
|
||||
License along with this library; if not, write to the Free Software
|
||||
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
||||
|
||||
Modified 2012 by Todd Krein (todd@krein.org) to implement repeated starts
|
||||
*/
|
||||
|
||||
#include <math.h>
|
||||
#include <stdlib.h>
|
||||
#include <inttypes.h>
|
||||
#include <avr/io.h>
|
||||
#include <avr/interrupt.h>
|
||||
#include <compat/twi.h>
|
||||
#include "Arduino.h" // for digitalWrite
|
||||
|
||||
#ifndef cbi
|
||||
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
|
||||
#endif
|
||||
|
||||
#ifndef sbi
|
||||
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
|
||||
#endif
|
||||
|
||||
#include "pins_arduino.h"
|
||||
#include "twi.h"
|
||||
|
||||
static volatile uint8_t twi_state;
|
||||
static volatile uint8_t twi_slarw;
|
||||
static volatile uint8_t twi_sendStop; // should the transaction end with a stop
|
||||
static volatile uint8_t twi_inRepStart; // in the middle of a repeated start
|
||||
|
||||
static void (*twi_onSlaveTransmit)(void);
|
||||
static void (*twi_onSlaveReceive)(uint8_t*, int);
|
||||
|
||||
static uint8_t twi_masterBuffer[TWI_BUFFER_LENGTH];
|
||||
static volatile uint8_t twi_masterBufferIndex;
|
||||
static volatile uint8_t twi_masterBufferLength;
|
||||
|
||||
static uint8_t twi_txBuffer[TWI_BUFFER_LENGTH];
|
||||
static volatile uint8_t twi_txBufferIndex;
|
||||
static volatile uint8_t twi_txBufferLength;
|
||||
|
||||
static uint8_t twi_rxBuffer[TWI_BUFFER_LENGTH];
|
||||
static volatile uint8_t twi_rxBufferIndex;
|
||||
|
||||
static volatile uint8_t twi_error;
|
||||
|
||||
/*
|
||||
* Function twi_init
|
||||
* Desc readys twi pins and sets twi bitrate
|
||||
* Input none
|
||||
* Output none
|
||||
*/
|
||||
void twi_init(void)
|
||||
{
|
||||
// initialize state
|
||||
twi_state = TWI_READY;
|
||||
twi_sendStop = true; // default value
|
||||
twi_inRepStart = false;
|
||||
|
||||
// activate internal pullups for twi.
|
||||
digitalWrite(SDA, 1);
|
||||
digitalWrite(SCL, 1);
|
||||
|
||||
// initialize twi prescaler and bit rate
|
||||
cbi(TWSR, TWPS0);
|
||||
cbi(TWSR, TWPS1);
|
||||
TWBR = ((F_CPU / TWI_FREQ) - 16) / 2;
|
||||
|
||||
/* twi bit rate formula from atmega128 manual pg 204
|
||||
SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR))
|
||||
note: TWBR should be 10 or higher for master mode
|
||||
It is 72 for a 16mhz Wiring board with 100kHz TWI */
|
||||
|
||||
// enable twi module, acks, and twi interrupt
|
||||
TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA);
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_disable
|
||||
* Desc disables twi pins
|
||||
* Input none
|
||||
* Output none
|
||||
*/
|
||||
void twi_disable(void)
|
||||
{
|
||||
// disable twi module, acks, and twi interrupt
|
||||
TWCR &= ~(_BV(TWEN) | _BV(TWIE) | _BV(TWEA));
|
||||
|
||||
// deactivate internal pullups for twi.
|
||||
digitalWrite(SDA, 0);
|
||||
digitalWrite(SCL, 0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_slaveInit
|
||||
* Desc sets slave address and enables interrupt
|
||||
* Input none
|
||||
* Output none
|
||||
*/
|
||||
void twi_setAddress(uint8_t address)
|
||||
{
|
||||
// set twi slave address (skip over TWGCE bit)
|
||||
TWAR = address << 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_setClock
|
||||
* Desc sets twi bit rate
|
||||
* Input Clock Frequency
|
||||
* Output none
|
||||
*/
|
||||
void twi_setFrequency(uint32_t frequency)
|
||||
{
|
||||
TWBR = ((F_CPU / frequency) - 16) / 2;
|
||||
|
||||
/* twi bit rate formula from atmega128 manual pg 204
|
||||
SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR))
|
||||
note: TWBR should be 10 or higher for master mode
|
||||
It is 72 for a 16mhz Wiring board with 100kHz TWI */
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_readFrom
|
||||
* Desc attempts to become twi bus master and read a
|
||||
* series of bytes from a device on the bus
|
||||
* Input address: 7bit i2c device address
|
||||
* data: pointer to byte array
|
||||
* length: number of bytes to read into array
|
||||
* sendStop: Boolean indicating whether to send a stop at the end
|
||||
* Output number of bytes read
|
||||
*/
|
||||
uint8_t twi_readFrom(uint8_t address, uint8_t* data, uint8_t length, uint8_t sendStop)
|
||||
{
|
||||
uint8_t i;
|
||||
|
||||
// ensure data will fit into buffer
|
||||
if(TWI_BUFFER_LENGTH < length){
|
||||
return 0;
|
||||
}
|
||||
|
||||
// wait until twi is ready, become master receiver
|
||||
while(TWI_READY != twi_state){
|
||||
continue;
|
||||
}
|
||||
twi_state = TWI_MRX;
|
||||
twi_sendStop = sendStop;
|
||||
// reset error state (0xFF.. no error occured)
|
||||
twi_error = 0xFF;
|
||||
|
||||
// initialize buffer iteration vars
|
||||
twi_masterBufferIndex = 0;
|
||||
twi_masterBufferLength = length-1; // This is not intuitive, read on...
|
||||
// On receive, the previously configured ACK/NACK setting is transmitted in
|
||||
// response to the received byte before the interrupt is signalled.
|
||||
// Therefor we must actually set NACK when the _next_ to last byte is
|
||||
// received, causing that NACK to be sent in response to receiving the last
|
||||
// expected byte of data.
|
||||
|
||||
// build sla+w, slave device address + w bit
|
||||
twi_slarw = TW_READ;
|
||||
twi_slarw |= address << 1;
|
||||
|
||||
if (true == twi_inRepStart) {
|
||||
// if we're in the repeated start state, then we've already sent the start,
|
||||
// (@@@ we hope), and the TWI statemachine is just waiting for the address byte.
|
||||
// We need to remove ourselves from the repeated start state before we enable interrupts,
|
||||
// since the ISR is ASYNC, and we could get confused if we hit the ISR before cleaning
|
||||
// up. Also, don't enable the START interrupt. There may be one pending from the
|
||||
// repeated start that we sent ourselves, and that would really confuse things.
|
||||
twi_inRepStart = false; // remember, we're dealing with an ASYNC ISR
|
||||
do {
|
||||
TWDR = twi_slarw;
|
||||
} while(TWCR & _BV(TWWC));
|
||||
TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE); // enable INTs, but not START
|
||||
}
|
||||
else
|
||||
// send start condition
|
||||
TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTA);
|
||||
|
||||
// wait for read operation to complete
|
||||
while(TWI_MRX == twi_state){
|
||||
continue;
|
||||
}
|
||||
|
||||
if (twi_masterBufferIndex < length)
|
||||
length = twi_masterBufferIndex;
|
||||
|
||||
// copy twi buffer to data
|
||||
for(i = 0; i < length; ++i){
|
||||
data[i] = twi_masterBuffer[i];
|
||||
}
|
||||
|
||||
return length;
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_writeTo
|
||||
* Desc attempts to become twi bus master and write a
|
||||
* series of bytes to a device on the bus
|
||||
* Input address: 7bit i2c device address
|
||||
* data: pointer to byte array
|
||||
* length: number of bytes in array
|
||||
* wait: boolean indicating to wait for write or not
|
||||
* sendStop: boolean indicating whether or not to send a stop at the end
|
||||
* Output 0 .. success
|
||||
* 1 .. length to long for buffer
|
||||
* 2 .. address send, NACK received
|
||||
* 3 .. data send, NACK received
|
||||
* 4 .. other twi error (lost bus arbitration, bus error, ..)
|
||||
*/
|
||||
uint8_t twi_writeTo(uint8_t address, uint8_t* data, uint8_t length, uint8_t wait, uint8_t sendStop)
|
||||
{
|
||||
uint8_t i;
|
||||
|
||||
// ensure data will fit into buffer
|
||||
if(TWI_BUFFER_LENGTH < length){
|
||||
return 1;
|
||||
}
|
||||
|
||||
// wait until twi is ready, become master transmitter
|
||||
while(TWI_READY != twi_state){
|
||||
continue;
|
||||
}
|
||||
twi_state = TWI_MTX;
|
||||
twi_sendStop = sendStop;
|
||||
// reset error state (0xFF.. no error occured)
|
||||
twi_error = 0xFF;
|
||||
|
||||
// initialize buffer iteration vars
|
||||
twi_masterBufferIndex = 0;
|
||||
twi_masterBufferLength = length;
|
||||
|
||||
// copy data to twi buffer
|
||||
for(i = 0; i < length; ++i){
|
||||
twi_masterBuffer[i] = data[i];
|
||||
}
|
||||
|
||||
// build sla+w, slave device address + w bit
|
||||
twi_slarw = TW_WRITE;
|
||||
twi_slarw |= address << 1;
|
||||
|
||||
// if we're in a repeated start, then we've already sent the START
|
||||
// in the ISR. Don't do it again.
|
||||
//
|
||||
if (true == twi_inRepStart) {
|
||||
// if we're in the repeated start state, then we've already sent the start,
|
||||
// (@@@ we hope), and the TWI statemachine is just waiting for the address byte.
|
||||
// We need to remove ourselves from the repeated start state before we enable interrupts,
|
||||
// since the ISR is ASYNC, and we could get confused if we hit the ISR before cleaning
|
||||
// up. Also, don't enable the START interrupt. There may be one pending from the
|
||||
// repeated start that we sent outselves, and that would really confuse things.
|
||||
twi_inRepStart = false; // remember, we're dealing with an ASYNC ISR
|
||||
do {
|
||||
TWDR = twi_slarw;
|
||||
} while(TWCR & _BV(TWWC));
|
||||
TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE); // enable INTs, but not START
|
||||
}
|
||||
else
|
||||
// send start condition
|
||||
TWCR = _BV(TWINT) | _BV(TWEA) | _BV(TWEN) | _BV(TWIE) | _BV(TWSTA); // enable INTs
|
||||
|
||||
// wait for write operation to complete
|
||||
while(wait && (TWI_MTX == twi_state)){
|
||||
continue;
|
||||
}
|
||||
|
||||
if (twi_error == 0xFF)
|
||||
return 0; // success
|
||||
else if (twi_error == TW_MT_SLA_NACK)
|
||||
return 2; // error: address send, nack received
|
||||
else if (twi_error == TW_MT_DATA_NACK)
|
||||
return 3; // error: data send, nack received
|
||||
else
|
||||
return 4; // other twi error
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_transmit
|
||||
* Desc fills slave tx buffer with data
|
||||
* must be called in slave tx event callback
|
||||
* Input data: pointer to byte array
|
||||
* length: number of bytes in array
|
||||
* Output 1 length too long for buffer
|
||||
* 2 not slave transmitter
|
||||
* 0 ok
|
||||
*/
|
||||
uint8_t twi_transmit(const uint8_t* data, uint8_t length)
|
||||
{
|
||||
uint8_t i;
|
||||
|
||||
// ensure data will fit into buffer
|
||||
if(TWI_BUFFER_LENGTH < (twi_txBufferLength+length)){
|
||||
return 1;
|
||||
}
|
||||
|
||||
// ensure we are currently a slave transmitter
|
||||
if(TWI_STX != twi_state){
|
||||
return 2;
|
||||
}
|
||||
|
||||
// set length and copy data into tx buffer
|
||||
for(i = 0; i < length; ++i){
|
||||
twi_txBuffer[twi_txBufferLength+i] = data[i];
|
||||
}
|
||||
twi_txBufferLength += length;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_attachSlaveRxEvent
|
||||
* Desc sets function called before a slave read operation
|
||||
* Input function: callback function to use
|
||||
* Output none
|
||||
*/
|
||||
void twi_attachSlaveRxEvent( void (*function)(uint8_t*, int) )
|
||||
{
|
||||
twi_onSlaveReceive = function;
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_attachSlaveTxEvent
|
||||
* Desc sets function called before a slave write operation
|
||||
* Input function: callback function to use
|
||||
* Output none
|
||||
*/
|
||||
void twi_attachSlaveTxEvent( void (*function)(void) )
|
||||
{
|
||||
twi_onSlaveTransmit = function;
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_reply
|
||||
* Desc sends byte or readys receive line
|
||||
* Input ack: byte indicating to ack or to nack
|
||||
* Output none
|
||||
*/
|
||||
void twi_reply(uint8_t ack)
|
||||
{
|
||||
// transmit master read ready signal, with or without ack
|
||||
if(ack){
|
||||
TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT) | _BV(TWEA);
|
||||
}else{
|
||||
TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWINT);
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_stop
|
||||
* Desc relinquishes bus master status
|
||||
* Input none
|
||||
* Output none
|
||||
*/
|
||||
void twi_stop(void)
|
||||
{
|
||||
// send stop condition
|
||||
TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT) | _BV(TWSTO);
|
||||
|
||||
// wait for stop condition to be exectued on bus
|
||||
// TWINT is not set after a stop condition!
|
||||
while(TWCR & _BV(TWSTO)){
|
||||
continue;
|
||||
}
|
||||
|
||||
// update twi state
|
||||
twi_state = TWI_READY;
|
||||
}
|
||||
|
||||
/*
|
||||
* Function twi_releaseBus
|
||||
* Desc releases bus control
|
||||
* Input none
|
||||
* Output none
|
||||
*/
|
||||
void twi_releaseBus(void)
|
||||
{
|
||||
// release bus
|
||||
TWCR = _BV(TWEN) | _BV(TWIE) | _BV(TWEA) | _BV(TWINT);
|
||||
|
||||
// update twi state
|
||||
twi_state = TWI_READY;
|
||||
}
|
||||
|
||||
ISR(TWI_vect)
|
||||
{
|
||||
switch(TW_STATUS){
|
||||
// All Master
|
||||
case TW_START: // sent start condition
|
||||
case TW_REP_START: // sent repeated start condition
|
||||
// copy device address and r/w bit to output register and ack
|
||||
TWDR = twi_slarw;
|
||||
twi_reply(1);
|
||||
break;
|
||||
|
||||
// Master Transmitter
|
||||
case TW_MT_SLA_ACK: // slave receiver acked address
|
||||
case TW_MT_DATA_ACK: // slave receiver acked data
|
||||
// if there is data to send, send it, otherwise stop
|
||||
if(twi_masterBufferIndex < twi_masterBufferLength){
|
||||
// copy data to output register and ack
|
||||
TWDR = twi_masterBuffer[twi_masterBufferIndex++];
|
||||
twi_reply(1);
|
||||
}else{
|
||||
if (twi_sendStop)
|
||||
twi_stop();
|
||||
else {
|
||||
twi_inRepStart = true; // we're gonna send the START
|
||||
// don't enable the interrupt. We'll generate the start, but we
|
||||
// avoid handling the interrupt until we're in the next transaction,
|
||||
// at the point where we would normally issue the start.
|
||||
TWCR = _BV(TWINT) | _BV(TWSTA)| _BV(TWEN) ;
|
||||
twi_state = TWI_READY;
|
||||
}
|
||||
}
|
||||
break;
|
||||
case TW_MT_SLA_NACK: // address sent, nack received
|
||||
twi_error = TW_MT_SLA_NACK;
|
||||
twi_stop();
|
||||
break;
|
||||
case TW_MT_DATA_NACK: // data sent, nack received
|
||||
twi_error = TW_MT_DATA_NACK;
|
||||
twi_stop();
|
||||
break;
|
||||
case TW_MT_ARB_LOST: // lost bus arbitration
|
||||
twi_error = TW_MT_ARB_LOST;
|
||||
twi_releaseBus();
|
||||
break;
|
||||
|
||||
// Master Receiver
|
||||
case TW_MR_DATA_ACK: // data received, ack sent
|
||||
// put byte into buffer
|
||||
twi_masterBuffer[twi_masterBufferIndex++] = TWDR;
|
||||
case TW_MR_SLA_ACK: // address sent, ack received
|
||||
// ack if more bytes are expected, otherwise nack
|
||||
if(twi_masterBufferIndex < twi_masterBufferLength){
|
||||
twi_reply(1);
|
||||
}else{
|
||||
twi_reply(0);
|
||||
}
|
||||
break;
|
||||
case TW_MR_DATA_NACK: // data received, nack sent
|
||||
// put final byte into buffer
|
||||
twi_masterBuffer[twi_masterBufferIndex++] = TWDR;
|
||||
if (twi_sendStop)
|
||||
twi_stop();
|
||||
else {
|
||||
twi_inRepStart = true; // we're gonna send the START
|
||||
// don't enable the interrupt. We'll generate the start, but we
|
||||
// avoid handling the interrupt until we're in the next transaction,
|
||||
// at the point where we would normally issue the start.
|
||||
TWCR = _BV(TWINT) | _BV(TWSTA)| _BV(TWEN) ;
|
||||
twi_state = TWI_READY;
|
||||
}
|
||||
break;
|
||||
case TW_MR_SLA_NACK: // address sent, nack received
|
||||
twi_stop();
|
||||
break;
|
||||
// TW_MR_ARB_LOST handled by TW_MT_ARB_LOST case
|
||||
|
||||
// Slave Receiver
|
||||
case TW_SR_SLA_ACK: // addressed, returned ack
|
||||
case TW_SR_GCALL_ACK: // addressed generally, returned ack
|
||||
case TW_SR_ARB_LOST_SLA_ACK: // lost arbitration, returned ack
|
||||
case TW_SR_ARB_LOST_GCALL_ACK: // lost arbitration, returned ack
|
||||
// enter slave receiver mode
|
||||
twi_state = TWI_SRX;
|
||||
// indicate that rx buffer can be overwritten and ack
|
||||
twi_rxBufferIndex = 0;
|
||||
twi_reply(1);
|
||||
break;
|
||||
case TW_SR_DATA_ACK: // data received, returned ack
|
||||
case TW_SR_GCALL_DATA_ACK: // data received generally, returned ack
|
||||
// if there is still room in the rx buffer
|
||||
if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){
|
||||
// put byte in buffer and ack
|
||||
twi_rxBuffer[twi_rxBufferIndex++] = TWDR;
|
||||
twi_reply(1);
|
||||
}else{
|
||||
// otherwise nack
|
||||
twi_reply(0);
|
||||
}
|
||||
break;
|
||||
case TW_SR_STOP: // stop or repeated start condition received
|
||||
// ack future responses and leave slave receiver state
|
||||
twi_releaseBus();
|
||||
// put a null char after data if there's room
|
||||
if(twi_rxBufferIndex < TWI_BUFFER_LENGTH){
|
||||
twi_rxBuffer[twi_rxBufferIndex] = '\0';
|
||||
}
|
||||
// callback to user defined callback
|
||||
twi_onSlaveReceive(twi_rxBuffer, twi_rxBufferIndex);
|
||||
// since we submit rx buffer to "wire" library, we can reset it
|
||||
twi_rxBufferIndex = 0;
|
||||
break;
|
||||
case TW_SR_DATA_NACK: // data received, returned nack
|
||||
case TW_SR_GCALL_DATA_NACK: // data received generally, returned nack
|
||||
// nack back at master
|
||||
twi_reply(0);
|
||||
break;
|
||||
|
||||
// Slave Transmitter
|
||||
case TW_ST_SLA_ACK: // addressed, returned ack
|
||||
case TW_ST_ARB_LOST_SLA_ACK: // arbitration lost, returned ack
|
||||
// enter slave transmitter mode
|
||||
twi_state = TWI_STX;
|
||||
// ready the tx buffer index for iteration
|
||||
twi_txBufferIndex = 0;
|
||||
// set tx buffer length to be zero, to verify if user changes it
|
||||
twi_txBufferLength = 0;
|
||||
// request for txBuffer to be filled and length to be set
|
||||
// note: user must call twi_transmit(bytes, length) to do this
|
||||
twi_onSlaveTransmit();
|
||||
// if they didn't change buffer & length, initialize it
|
||||
if(0 == twi_txBufferLength){
|
||||
twi_txBufferLength = 1;
|
||||
twi_txBuffer[0] = 0x00;
|
||||
}
|
||||
// transmit first byte from buffer, fall
|
||||
case TW_ST_DATA_ACK: // byte sent, ack returned
|
||||
// copy data to output register
|
||||
TWDR = twi_txBuffer[twi_txBufferIndex++];
|
||||
// if there is more to send, ack, otherwise nack
|
||||
if(twi_txBufferIndex < twi_txBufferLength){
|
||||
twi_reply(1);
|
||||
}else{
|
||||
twi_reply(0);
|
||||
}
|
||||
break;
|
||||
case TW_ST_DATA_NACK: // received nack, we are done
|
||||
case TW_ST_LAST_DATA: // received ack, but we are done already!
|
||||
// ack future responses
|
||||
twi_reply(1);
|
||||
// leave slave receiver state
|
||||
twi_state = TWI_READY;
|
||||
break;
|
||||
|
||||
// All
|
||||
case TW_NO_INFO: // no state information
|
||||
break;
|
||||
case TW_BUS_ERROR: // bus error, illegal stop/start
|
||||
twi_error = TW_BUS_ERROR;
|
||||
twi_stop();
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
55
Firmware/twi.h
Normal file
55
Firmware/twi.h
Normal file
@ -0,0 +1,55 @@
|
||||
/*
|
||||
twi.h - TWI/I2C library for Wiring & Arduino
|
||||
Copyright (c) 2006 Nicholas Zambetti. All right reserved.
|
||||
|
||||
This library is free software; you can redistribute it and/or
|
||||
modify it under the terms of the GNU Lesser General Public
|
||||
License as published by the Free Software Foundation; either
|
||||
version 2.1 of the License, or (at your option) any later version.
|
||||
|
||||
This library is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
Lesser General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU Lesser General Public
|
||||
License along with this library; if not, write to the Free Software
|
||||
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
||||
*/
|
||||
|
||||
#ifndef twi_h
|
||||
#define twi_h
|
||||
|
||||
#include <inttypes.h>
|
||||
|
||||
//#define ATMEGA8
|
||||
|
||||
#ifndef TWI_FREQ
|
||||
#define TWI_FREQ 400000L
|
||||
#endif
|
||||
|
||||
#ifndef TWI_BUFFER_LENGTH
|
||||
#define TWI_BUFFER_LENGTH 32
|
||||
#endif
|
||||
|
||||
#define TWI_READY 0
|
||||
#define TWI_MRX 1
|
||||
#define TWI_MTX 2
|
||||
#define TWI_SRX 3
|
||||
#define TWI_STX 4
|
||||
|
||||
void twi_init(void);
|
||||
void twi_disable(void);
|
||||
void twi_setAddress(uint8_t);
|
||||
void twi_setFrequency(uint32_t);
|
||||
uint8_t twi_readFrom(uint8_t, uint8_t*, uint8_t, uint8_t);
|
||||
uint8_t twi_writeTo(uint8_t, uint8_t*, uint8_t, uint8_t, uint8_t);
|
||||
uint8_t twi_transmit(const uint8_t*, uint8_t);
|
||||
void twi_attachSlaveRxEvent( void (*)(uint8_t*, int) );
|
||||
void twi_attachSlaveTxEvent( void (*)(void) );
|
||||
void twi_reply(uint8_t);
|
||||
void twi_stop(void);
|
||||
void twi_releaseBus(void);
|
||||
|
||||
#endif
|
||||
|
||||
Loading…
Reference in New Issue
Block a user