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/*
Copyright (c) 2013 Arduino LLC. 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
*/
#include "Bridge.h"
void BridgeClass::begin() {
if (started)
return;
started = true;
// TODO: A more robust restart
// Bridge startup:
// - If the bridge is not running starts it safely
print(CTRL_C);
print(F("\n"));
delay(500);
// Wait for OpenWRT message
// "Press enter to activate console"
print(F("\ncd /usr/lib/python2.7/bridge\n"));
delay(100);
print(F("python -B bridge.py\n"));
delay(1000);
dropAll();
// - If the bridge was already running previous commands
// are ignored as "invalid packets".
// Reset the brigde
uint8_t cmd[] = {'X','X'};
transfer(cmd, 2);
}
uint8_t BridgeClass::runCommand(String &command) {
// TODO: do it in a more efficient way
String cmd = "R" + command;
uint8_t res[1];
transfer((uint8_t*)cmd.c_str(), cmd.length(), res, 1);
return res[0];
}
bool BridgeClass::commandIsRunning(uint8_t handle) {
uint8_t cmd[] = {'r', handle};
uint8_t res[1];
transfer(cmd, 2, res, 1);
return (res[0] == 1);
}
unsigned int BridgeClass::commandExitValue(uint8_t handle) {
uint8_t cmd[] = {'W', handle};
uint8_t res[2];
transfer(cmd, 2, res, 2);
return (res[0] << 8) + res[1];
}
void BridgeClass::cleanCommand(uint8_t handle) {
uint8_t cmd[] = {'w', handle};
transfer(cmd, 2);
}
unsigned int BridgeClass::commandOutputAvailable(uint8_t handle) {
uint8_t cmd[] = {'o', handle};
uint8_t res[1];
transfer(cmd, 2, res, 1);
return res[0];
}
unsigned int BridgeClass::readCommandOutput(uint8_t handle,
uint8_t *buffer, unsigned int size) {
if (size > 255)
size = 255;
uint8_t cmd[] = {'O', handle, size};
return transfer(cmd, 3, buffer, size);
}
void BridgeClass::writeCommandInput(uint8_t handle,
uint8_t *buff, unsigned int size) {
// TODO: do it in a more efficient way
uint8_t *tmp = new uint8_t[size+2];
tmp[0] = 'I';
tmp[1] = handle;
memcpy(tmp+2, buff, size);
transfer(tmp, size+2);
delete[] tmp;
}
void BridgeClass::crcUpdate(uint8_t c) {
CRC = CRC ^ c;
CRC = (CRC >> 8) + (CRC << 8);
}
void BridgeClass::crcReset() {
CRC = 0xAAAA;
}
void BridgeClass::crcWrite() {
write((char)(CRC >> 8));
write((char)(CRC & 0xFF));
}
bool BridgeClass::crcCheck(uint16_t _CRC) {
return CRC == _CRC;
}
uint8_t BridgeClass::transfer(uint8_t *buff, uint8_t len,
uint8_t *rxbuff, uint8_t rxlen)
{
for ( ; ; delay(100), dropAll() /* Delay for retransmission */) {
// Send packet
crcReset();
write((char)0xFF); // Start of packet (0xFF)
crcUpdate(0xFF);
write((char)index); // Message index
crcUpdate(index);
write((char)len); // Message length
crcUpdate(len);
for (uint8_t i=0; i<len; i++) { // Payload
write((char)buff[i]);
crcUpdate(buff[i]);
}
crcWrite(); // CRC
// Wait for ACK in 100ms
if (timedRead(100) != 0xFF)
continue;
crcReset();
crcUpdate(0xFF);
// Check packet index
if (timedRead(5) != index)
continue;
crcUpdate(index);
// Recv len
uint8_t l = timedRead(5);
if (l < 0)
continue;
crcUpdate(l);
// Recv data
for (uint8_t i=0; i<l; i++) {
int c = timedRead(5);
if (c < 0)
continue;
// Cut received data if rxbuffer is too small
if (i < rxlen)
rxbuff[i] = c;
crcUpdate(c);
}
// Check CRC
int crc_hi = timedRead(5);
if (crc_hi < 0)
continue;
int crc_lo = timedRead(5);
if (crc_lo < 0)
continue;
if (!crcCheck((crc_hi<<8)+crc_lo))
continue;
// Increase index
index++;
// Return bytes received
if (l > rxlen)
return rxlen;
return l;
}
}
int BridgeClass::timedRead(unsigned int timeout) {
int c;
unsigned long _startMillis = millis();
do {
c = read();
if (c >= 0) return c;
} while(millis() - _startMillis < timeout);
return -1; // -1 indicates timeout
}
void BridgeClass::dropAll() {
while (available() > 0) {
read();
}
}
// Bridge instance
#ifdef __AVR_ATmega32U4__
// Leonardo variants (where HardwareSerial is Serial1)
SerialBridgeClass Bridge(Serial1);
#else
SerialBridgeClass Bridge(Serial);
#endif
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