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Arduino/hardware/sam/libraries/Wire/Wire.cpp

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/*
* TwoWire.h - TWI/I2C library for Arduino Due
* Copyright (c) 2011 Cristian Maglie <c.maglie@bug.st>.
* All rights reserved.
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*
* 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
*/
extern "C" {
#include <string.h>
#include "twi.h"
}
#include "Wire.h"
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static inline bool TWI_FailedAcknowledge(Twi *pTwi) {
return pTwi->TWI_SR & TWI_SR_NACK;
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}
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static inline bool TWI_WaitTransferComplete(Twi *_twi, uint32_t _timeout) {
while (!TWI_TransferComplete(_twi)) {
if (TWI_FailedAcknowledge(_twi))
return false;
if (--_timeout == 0)
return false;
}
return true;
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}
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static inline bool TWI_WaitByteSent(Twi *_twi, uint32_t _timeout) {
while (!TWI_ByteSent(_twi)) {
if (TWI_FailedAcknowledge(_twi))
return false;
if (--_timeout == 0)
return false;
}
return true;
}
static inline bool TWI_WaitByteReceived(Twi *_twi, uint32_t _timeout) {
while (!TWI_ByteReceived(_twi)) {
if (TWI_FailedAcknowledge(_twi))
return false;
if (--_timeout == 0)
return false;
}
return true;
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}
static inline bool TWI_STATUS_SVREAD(uint32_t status) {
return (status & TWI_SR_SVREAD) == TWI_SR_SVREAD;
}
static inline bool TWI_STATUS_SVACC(uint32_t status) {
return (status & TWI_SR_SVACC) == TWI_SR_SVACC;
}
static inline bool TWI_STATUS_GACC(uint32_t status) {
return (status & TWI_SR_GACC) == TWI_SR_GACC;
}
static inline bool TWI_STATUS_EOSACC(uint32_t status) {
return (status & TWI_SR_EOSACC) == TWI_SR_EOSACC;
}
static inline bool TWI_STATUS_NACK(uint32_t status) {
return (status & TWI_SR_NACK) == TWI_SR_NACK;
}
TwoWire::TwoWire(Twi *_twi, void(*_beginCb)(void)) :
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twi(_twi), rxBufferIndex(0), rxBufferLength(0), txAddress(0),
txBufferLength(0), srvBufferIndex(0), srvBufferLength(0), status(
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UNINITIALIZED), onBeginCallback(_beginCb) {
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// Empty
}
void TwoWire::begin(void) {
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if (onBeginCallback)
onBeginCallback();
TWI_ConfigureMaster(twi, TWI_CLOCK, VARIANT_MCK);
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status = MASTER_IDLE;
}
void TwoWire::begin(uint8_t address) {
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if (onBeginCallback)
onBeginCallback();
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TWI_ConfigureSlave(twi, address);
status = SLAVE_IDLE;
TWI_EnableIt(twi, TWI_IER_SVACC);
//| TWI_IER_RXRDY | TWI_IER_TXRDY | TWI_IER_TXCOMP);
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}
void TwoWire::begin(int address) {
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begin((uint8_t) address);
}
uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity) {
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if (quantity > BUFFER_LENGTH)
quantity = BUFFER_LENGTH;
// perform blocking read into buffer
int readed = 0;
TWI_StartRead(twi, address, 0, 0);
do {
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// Stop condition must be set during the reception of last byte
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if (readed + 1 == quantity)
TWI_SendSTOPCondition( twi);
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TWI_WaitByteReceived(twi, RECV_TIMEOUT);
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rxBuffer[readed++] = TWI_ReadByte(twi);
} while (readed < quantity);
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TWI_WaitTransferComplete(twi, RECV_TIMEOUT);
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// set rx buffer iterator vars
rxBufferIndex = 0;
rxBufferLength = readed;
return readed;
}
uint8_t TwoWire::requestFrom(int address, int quantity) {
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return requestFrom((uint8_t) address, (uint8_t) quantity);
}
void TwoWire::beginTransmission(uint8_t address) {
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status = MASTER_SEND;
// save address of target and empty buffer
txAddress = address;
txBufferLength = 0;
}
void TwoWire::beginTransmission(int address) {
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beginTransmission((uint8_t) address);
}
uint8_t TwoWire::endTransmission(void) {
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// transmit buffer (blocking)
TWI_StartWrite(twi, txAddress, 0, 0, txBuffer[0]);
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TWI_WaitByteSent(twi, XMIT_TIMEOUT);
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int sent = 1;
while (sent < txBufferLength) {
TWI_WriteByte(twi, txBuffer[sent++]);
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TWI_WaitByteSent(twi, XMIT_TIMEOUT);
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}
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TWI_Stop( twi);
TWI_WaitTransferComplete(twi, XMIT_TIMEOUT);
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// empty buffer
txBufferLength = 0;
status = MASTER_IDLE;
return sent;
}
void TwoWire::write(uint8_t data) {
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if (status == MASTER_SEND) {
if (txBufferLength >= BUFFER_LENGTH)
return;
txBuffer[txBufferLength++] = data;
} else {
if (srvBufferLength >= BUFFER_LENGTH)
return;
srvBuffer[srvBufferLength++] = data;
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}
}
void TwoWire::write(const uint8_t *data, size_t quantity) {
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if (status == MASTER_SEND) {
for (size_t i = 0; i < quantity; ++i) {
if (txBufferLength >= BUFFER_LENGTH)
return;
txBuffer[txBufferLength++] = data[i];
}
} else {
for (size_t i = 0; i < quantity; ++i) {
if (srvBufferLength >= BUFFER_LENGTH)
return;
srvBuffer[srvBufferLength++] = data[i];
}
}
}
void TwoWire::write(const char *data) {
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write((uint8_t*) data, strlen(data));
}
int TwoWire::available(void) {
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return rxBufferLength - rxBufferIndex;
}
int TwoWire::read(void) {
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if (rxBufferIndex < rxBufferLength)
return rxBuffer[rxBufferIndex++];
return -1;
}
int TwoWire::peek(void) {
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if (rxBufferIndex < rxBufferLength)
return rxBuffer[rxBufferIndex];
return -1;
}
void TwoWire::flush(void) {
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// Do nothing, use endTransmission(..) to force
// data transfer.
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}
void TwoWire::onReceive(void(*function)(int)) {
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onReceiveCallback = function;
}
void TwoWire::onRequest(void(*function)(void)) {
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onRequestCallback = function;
}
void TwoWire::onService(void) {
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// Retrieve interrupt status
uint32_t sr = TWI_GetStatus(twi);
if (status == SLAVE_IDLE && TWI_STATUS_SVACC(sr)) {
TWI_DisableIt(twi, TWI_IDR_SVACC);
TWI_EnableIt(twi, TWI_IER_RXRDY | TWI_IER_GACC | TWI_IER_NACK
| TWI_IER_EOSACC | TWI_IER_SCL_WS | TWI_IER_TXCOMP);
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srvBufferLength = 0;
srvBufferIndex = 0;
// Detect if we should go into RECV or SEND status
// SVREAD==1 means *master* reading -> SLAVE_SEND
if (!TWI_STATUS_SVREAD(sr)) {
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status = SLAVE_RECV;
} else {
status = SLAVE_SEND;
// Alert calling program to generate a response ASAP
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if (onRequestCallback)
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onRequestCallback();
else
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// create a default 1-byte response
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write((uint8_t) 0);
}
}
if (status != SLAVE_IDLE) {
if (TWI_STATUS_TXCOMP(sr) && TWI_STATUS_EOSACC(sr)) {
if (status == SLAVE_RECV && onReceiveCallback) {
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// Copy data into rxBuffer
// (allows to receive another packet while the
// user program reads actual data)
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for (uint8_t i = 0; i < srvBufferLength; ++i)
rxBuffer[i] = srvBuffer[i];
rxBufferIndex = 0;
rxBufferLength = srvBufferLength;
// Alert calling program
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onReceiveCallback( rxBufferLength);
}
// Transfer completed
TWI_EnableIt(twi, TWI_SR_SVACC);
TWI_DisableIt(twi, TWI_IDR_RXRDY | TWI_IDR_GACC | TWI_IDR_NACK
| TWI_IDR_EOSACC | TWI_IDR_SCL_WS | TWI_IER_TXCOMP);
status = SLAVE_IDLE;
}
}
if (status == SLAVE_RECV) {
if (TWI_STATUS_RXRDY(sr)) {
if (srvBufferLength < BUFFER_LENGTH)
srvBuffer[srvBufferLength++] = TWI_ReadByte(twi);
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}
}
if (status == SLAVE_SEND) {
if (TWI_STATUS_TXRDY(sr) && !TWI_STATUS_NACK(sr)) {
uint8_t c = 'x';
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if (srvBufferIndex < srvBufferLength)
c = srvBuffer[srvBufferIndex++];
TWI_WriteByte(twi, c);
}
}
}
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#if WIRE_INTERFACES_COUNT > 0
static void Wire_Init(void) {
PMC_EnablePeripheral( WIRE_INTERFACE_ID);
PIO_Configure(g_APinDescription[PIN_WIRE_SDA].pPort,
g_APinDescription[PIN_WIRE_SDA].ulPinType,
g_APinDescription[PIN_WIRE_SDA].ulPin,
g_APinDescription[PIN_WIRE_SDA].ulPinConfiguration);
PIO_Configure(g_APinDescription[PIN_WIRE_SCL].pPort,
g_APinDescription[PIN_WIRE_SCL].ulPinType,
g_APinDescription[PIN_WIRE_SCL].ulPin,
g_APinDescription[PIN_WIRE_SCL].ulPinConfiguration);
NVIC_DisableIRQ(TWI1_IRQn);
NVIC_ClearPendingIRQ(TWI1_IRQn);
NVIC_SetPriority(TWI1_IRQn, 0);
NVIC_EnableIRQ(TWI1_IRQn);
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}
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TwoWire Wire = TwoWire(WIRE_INTERFACE, Wire_Init);
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void WIRE_ISR_HANDLER(void) {
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Wire.onService();
}
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#endif
#if WIRE_INTERFACES_COUNT > 1
static void Wire1_Init(void) {
PMC_EnablePeripheral( WIRE1_INTERFACE_ID);
PIO_Configure(g_APinDescription[PIN_WIRE1_SDA].pPort,
g_APinDescription[PIN_WIRE1_SDA].ulPinType,
g_APinDescription[PIN_WIRE1_SDA].ulPin,
g_APinDescription[PIN_WIRE1_SDA].ulPinConfiguration);
PIO_Configure(g_APinDescription[PIN_WIRE1_SCL].pPort,
g_APinDescription[PIN_WIRE1_SCL].ulPinType,
g_APinDescription[PIN_WIRE1_SCL].ulPin,
g_APinDescription[PIN_WIRE1_SCL].ulPinConfiguration);
}
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TwoWire Wire1 = TwoWire(WIRE1_INTERFACE, Wire1_Init);
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void WIRE1_ISR_HANDLER(void) {
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Wire1.onService();
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}
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#endif