Added Wire lib for ARM

hardware/sam/libraries/Wire/Wire.cpp

@@ -0,0 +1,261 @@
+/*
+ * DueWire.cpp - TWI/I2C library Arduino Due
+ * Copyright (c) 2011 Cristian Maglie.  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
+ */
+
+extern "C" {
+#include <string.h>
+#include <inttypes.h>
+#include "twi.h"
+}
+
+#include "Wire.h"
+
+static inline void TWI_WaitTransferComplete(Twi *_twi) {
+	while (!TWI_TransferComplete(_twi))
+		;
+}
+
+static inline void TWI_WaitByteSent(Twi *_twi) {
+	while (!TWI_ByteSent(_twi))
+		;
+}
+
+static inline void TWI_WaitByteReceived(Twi *_twi) {
+	while (!TWI_ByteReceived(_twi))
+		;
+}
+
+static inline bool TWI_STATUS_SVREAD(uint32_t status) {
+	return (status & TWI_SR_SVREAD) == TWI_SR_SVREAD;
+}
+
+DueWire::DueWire(Twi *_twi) :
+	twi(_twi), rxBufferIndex(0), rxBufferLength(0), txAddress(0),
+			txBufferLength(0), srvBufferIndex(0), srvBufferLength(0), status(
+					UNINITIALIZED) {
+	// Empty
+}
+
+void DueWire::begin(void) {
+	// TODO: correct clock values
+	TWI_ConfigureMaster(twi, 200000, 200000);
+	status = MASTER_IDLE;
+}
+
+void DueWire::begin(uint8_t address) {
+	TWI_ConfigureSlave(twi, address);
+	status = SLAVE_IDLE;
+	TWI_EnableIt(twi, TWI_IER_RXRDY | TWI_IER_TXRDY | TWI_IER_TXCOMP);
+}
+
+void DueWire::begin(int address) {
+	begin((uint8_t) address);
+}
+
+uint8_t DueWire::requestFrom(uint8_t address, uint8_t quantity) {
+	if (quantity > BUFFER_LENGTH)
+		quantity = BUFFER_LENGTH;
+
+	// perform blocking read into buffer
+	int readed = 0;
+	TWI_StartRead(twi, address, 0, 0);
+	do {
+		// Stop condition must be set during the receprion of last byte
+		if (readed + 1 == quantity)
+			TWI_SendSTOPCondition( twi);
+
+		TWI_WaitByteReceived( twi);
+		rxBuffer[readed++] = TWI_ReadByte(twi);
+	} while (readed < quantity);
+	TWI_WaitTransferComplete( twi);
+
+	// set rx buffer iterator vars
+	rxBufferIndex = 0;
+	rxBufferLength = readed;
+
+	return readed;
+}
+
+uint8_t DueWire::requestFrom(int address, int quantity) {
+	return requestFrom((uint8_t) address, (uint8_t) quantity);
+}
+
+void DueWire::beginTransmission(uint8_t address) {
+	status = MASTER_SEND;
+
+	// save address of target and empty buffer
+	txAddress = address;
+	txBufferLength = 0;
+}
+
+void DueWire::beginTransmission(int address) {
+	beginTransmission((uint8_t) address);
+}
+
+uint8_t DueWire::endTransmission(void) {
+	// transmit buffer (blocking)
+	TWI_StartWrite(twi, txAddress, 0, 0, txBuffer[0]);
+	TWI_WaitByteSent( twi);
+	int sent = 1;
+	while (sent < txBufferLength) {
+		TWI_WriteByte(twi, txBuffer[sent++]);
+		TWI_WaitByteSent(twi);
+	}
+	TWI_Stop(twi);
+	TWI_WaitTransferComplete(twi);
+
+	// empty buffer
+	txBufferLength = 0;
+
+	status = MASTER_IDLE;
+	return sent;
+}
+
+void DueWire::write(uint8_t data) {
+	if (status == MASTER_SEND) {
+		if (txBufferLength >= BUFFER_LENGTH)
+			return;
+		txBuffer[txBufferLength++] = data;
+	} else {
+		if (srvBufferLength >= BUFFER_LENGTH)
+			return;
+		srvBuffer[srvBufferIndex++] = data;
+	}
+}
+
+void DueWire::write(const uint8_t *data, size_t quantity) {
+	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 DueWire::write(const char *data) {
+	write((uint8_t*) data, strlen(data));
+}
+
+int DueWire::available(void) {
+	return rxBufferLength - rxBufferIndex;
+}
+
+int DueWire::read(void) {
+	if (rxBufferIndex < rxBufferLength)
+		return rxBuffer[rxBufferIndex++];
+	return -1;
+}
+
+int DueWire::peek(void) {
+	if (rxBufferIndex < rxBufferLength)
+		return rxBuffer[rxBufferIndex];
+	return -1;
+}
+
+void DueWire::flush(void) {
+	// XXX: to be implemented.
+}
+
+void DueWire::onReceive(void(*function)(int)) {
+	onReceiveCallback = function;
+}
+
+void DueWire::onRequest(void(*function)(void)) {
+	onRequestCallback = function;
+}
+
+void DueWire::onService(void) {
+	// Retrieve interrupt status
+	uint32_t sr = TWI_GetMaskedStatus(twi);
+
+	// Detect if we should go into RECV or SEND status
+	if (status == SLAVE_IDLE) {
+		srvBufferLength = 0;
+		if (TWI_STATUS_SVREAD(sr)) {
+			status = SLAVE_RECV;
+		} else {
+			srvBufferIndex = 0;
+			status = SLAVE_SEND;
+
+			// Alert calling program to generate a response ASAP
+			if (onRequestCallback != NULL)
+				onRequestCallback();
+			else
+				// default response
+				write((uint8_t) 0);
+		}
+	}
+
+	// Receive packet
+	if (status == SLAVE_RECV) {
+		if (TWI_STATUS_RXRDY(sr)) {
+			if (srvBufferLength < BUFFER_LENGTH)
+				srvBuffer[srvBufferLength++] = TWI_ReadByte(twi);
+		}
+		if (TWI_STATUS_TXCOMP(sr)) {
+			// Receive completed
+			status = SLAVE_IDLE;
+
+			// Alert calling program
+			if (onReceiveCallback != NULL) {
+				// Copy data into rxBuffer
+				// (allows to receive another packet while
+				// the main application reads actual data)
+				for (uint8_t i = 0; i < srvBufferLength; ++i)
+					rxBuffer[i] = srvBuffer[i];
+				rxBufferIndex = 0;
+				rxBufferLength = srvBufferLength;
+
+				onReceiveCallback( rxBufferLength);
+			}
+		}
+	}
+
+	// Send packet
+	if (status == SLAVE_SEND) {
+		if (TWI_STATUS_TXRDY(sr)) {
+			uint8_t c = 0;
+			if (srvBufferIndex < srvBufferLength)
+				c = srvBuffer[srvBufferIndex++];
+			TWI_WriteByte(twi, c);
+		}
+
+		if (TWI_STATUS_TXCOMP(sr)) {
+			// Transmission complete
+			status = SLAVE_IDLE;
+		}
+	}
+}
+
+DueWire Wire = DueWire(TWI0);
+DueWire Wire2 = DueWire(TWI1);
+
+void TWI0_IrqHandler(void) {
+	Wire.onService();
+}
+
+void TWI1_IrqHandler(void) {
+	Wire2.onService();
+}