IanF
/
OneWireArduinoSlaveATTINY85
forked from youen/OneWireArduinoSlave
3
2
Fork 1
Code Issues 1 Pull Requests Releases Wiki Activity
Browse Source

search rom algorithm almost working (but code is in an awful state, and master doesn't recognize the ROM yet, maybe a CRC issue)

timer1
Youen Toupin 10 years ago
parent
68f4fce878
commit
74b3f2100e
1 changed files with 149 additions and 160 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 309
      OneWireIO.ino

309
OneWireIO.ino
Unescape View File

@ -12,10 +12,9 @@
#define PresenceWaitDuration 30
#define PresenceDuration 300
#define BitZeroMinDuration 20
#define BitZeroMaxDuration 75
#define ReadBitSamplingTime 13 // the theorical time is about 30us, but given various overhead, this is the empirical delay I've found works best (on Arduino Uno)
#define SendBitDuration 30
#define SendBitDuration 35
const byte InvalidBit = (byte)-1;
const byte IncompleteBit = (byte)-2;
@ -30,7 +29,6 @@ enum OwStatus
{
OS_WaitReset,
OS_Presence,
OS_AfterPresence,
OS_WaitCommand,
OS_SearchRom,
};
@ -55,15 +53,7 @@ void owRelease()
owOutTestPin.writeHigh();
}
void owWrite(bool value)
{
if (value)
owRelease();
else
owPullLow();
}
unsigned long resetStart = (unsigned long)-1;
volatile unsigned long resetStart = (unsigned long)-1;
unsigned long lastReset = (unsigned long)-1;
unsigned long bitStart = (unsigned long)-1;
byte receivingByte = 0;
@ -79,7 +69,7 @@ void setup()
led.writeLow();
cli(); // disable interrupts
attachInterrupt(InterruptNumber,onewireInterrupt,CHANGE);
attachInterrupt(InterruptNumber,onewireInterrupt,FALLING);
// set timer0 interrupt at 250KHz (actually depends on compare match register OCR0A)
// 4us between each tick
@ -99,11 +89,13 @@ void loop()
{
//if ((count++) % 1000 == 0)
// led.write(!led.read());
cli();//disable interrupts
cli();//disable interrupts
SerialChannel::swap();
sei();//enable interrupts
sei();//enable interrupts
SerialChannel::flush();
owHandleReset();
}
void(*timerEvent)() = 0;
@ -127,200 +119,195 @@ void owError(const char* message)
status = OS_WaitReset;
}
void owResetError()
void owClearError()
{
led.writeLow();
}
void onewireInterrupt(void)
void owHandleReset()
{
bool state = owPin.read();
unsigned long now = micros();
//led.write(state);
if (!state)
resetStart = now;
// handle reset
if (state)
unsigned long localResetStart = resetStart;
if (owPin.read())
{
unsigned long resetDuration = resetStart == (unsigned long)-1 ? (unsigned long)-1 : now - resetStart;
resetStart = (unsigned long)-1;
lastReset = now;
if (resetDuration >= ResetMinDuration && resetDuration <= ResetMaxDuration)
{
//debug.SC_APPEND_STR_TIME("reset", now);
owResetError();
status = OS_Presence;
setTimerEvent(PresenceWaitDuration - (micros() - now), &beginPresence);
return;
}
}
if (status == OS_AfterPresence)
else if (localResetStart != (unsigned long)-1)
{
status = OS_WaitCommand;
receivingByte = 0;
receivingBitPos = 0;
bitStart = (unsigned long)-1;
if (state)
unsigned long resetDuration = micros() - localResetStart;
if (resetDuration >= ResetMinDuration)
{
// this is the rising edge of end-of-presence ; don't try to interpret it as a bit
return;
}
}
// read bytes
if (status == OS_WaitCommand)
{
byte bit = interpretReceivedEdgeAsBit(state, now);
if (bit != IncompleteBit)
{
if (bit == InvalidBit)
return;
receivingByte |= (bit << receivingBitPos);
++receivingBitPos;
if (receivingBitPos == 8)
// wait for master to release the pin (or timeout if the pin is pulled low for too long)
unsigned long now = micros();
while (!owPin.read())
{
debug.SC_APPEND_STR_INT("received byte", (long)receivingByte);
if (status == OS_WaitCommand && receivingByte == 0xF0)
if (resetStart != localResetStart)
return;
now = micros();
if (now - localResetStart > ResetMaxDuration)
{
status = OS_SearchRom;
searchROMReadingMasterResponseBit = false;
searchROMSendingInverse = false;
searchROMCurrentByte = 0;
searchROMCurrentBit = 0;
owError("Reset too long");
return;
}
receivingBitPos = 0;
receivingByte = 0;
}
cli();
owClearError();
lastReset = now;
status = OS_Presence;
setTimerEvent(PresenceWaitDuration - (micros() - now), &beginPresence);
sei();
}
}
}
if (status == OS_SearchRom)
void onewireInterrupt()
{
//owOutTestPin.writeLow();
onewireInterruptImpl();
//owOutTestPin.writeHigh();
}
//bool debugState = false;
volatile unsigned long lastInterrupt = 0;
void onewireInterruptImpl(void)
{
unsigned long now = micros();
if (now < lastInterrupt + 20)
return; // don't react to our own actions
lastInterrupt = now;
//debugState = !debugState;
//owOutTestPin.write(debugState);
//led.write(state);
resetStart = now;
// read bytes
switch (status) {
case OS_WaitCommand:
{
byte currentByte = owROM[searchROMCurrentByte];
bool currentBit = bitRead(currentByte, searchROMCurrentBit);
bool bit = readBit();
if (searchROMReadingMasterResponseBit)
receivingByte |= ((bit ? 1 : 0) << receivingBitPos);
++receivingBitPos;
if (receivingBitPos == 8)
{
byte bit = interpretReceivedEdgeAsBit(state, now);
if (bit != IncompleteBit)
byte receivedByte = receivingByte;
receivingBitPos = 0;
receivingByte = 0;
//debug.SC_APPEND_STR_INT("received byte", (long)receivedByte);
if (status == OS_WaitCommand && receivedByte == 0xF0)
{
status = OS_SearchRom;
searchROMReadingMasterResponseBit = false;
if (bit == InvalidBit)
return;
if ((bit == 1) != currentBit)
{
debug.SC_APPEND_STR_TIME("Master didn't send our bit, leaving ROM search", now);
status = OS_WaitReset;
}
searchROMSendingInverse = false;
searchROMCurrentByte = 0;
searchROMCurrentBit = 0;
attachInterrupt(InterruptNumber, onewireInterruptSearchROM, FALLING);
return;
}
}
else
{
if (!state)
{
// master is pulling low, we must send our bit
bool bitToSend = searchROMSendingInverse ? !currentBit : currentBit;
sendBit(bitToSend);
if (bitToSend)
debug.SC_APPEND_STR_TIME("Sent ROM search bit : 1", now);
else
debug.SC_APPEND_STR_TIME("Sent ROM search bit : 0", now);
if (searchROMSendingInverse)
{
searchROMSendingInverse = false;
searchROMReadingMasterResponseBit = true;
}
else
{
searchROMSendingInverse = true;
}
} break;
if (searchROMCurrentBit == 8)
{
++searchROMCurrentByte;
searchROMCurrentBit = 0;
debug.SC_APPEND_STR_TIME("sent another ROM byte", now);
}
if (searchROMCurrentByte == 8)
{
searchROMCurrentByte = 0;
status = OS_WaitReset;
debug.SC_APPEND_STR_TIME("ROM sent entirely", now);
}
}
else
{
debug.SC_APPEND_STR_TIME("Search ROM : seen rising edge", now);
}
}
case OS_SearchRom:
{
} break;
}
}
byte interpretReceivedEdgeAsBit(bool wireState, unsigned long now)
bool ignoreNextFallingEdge = false;
void onewireInterruptSearchROM()
{
if (!wireState)
/*unsigned long now = micros();
if (now < lastInterrupt + 20)
return; // don't react to our own actions
lastInterrupt = now;*/
if (ignoreNextFallingEdge)
{
// master just pulled low, this is a bit start
//debug.SC_APPEND_STR_TIME("bit start", now);
bitStart = now;
return IncompleteBit;
ignoreNextFallingEdge = false;
return;
}
else
if (searchROMReadingMasterResponseBit)
{
if (bitStart == (unsigned long)-1)
{
//owError("Invalid read sequence");
//return InvalidBit;
bool bit = readBit();
byte currentByte = owROM[searchROMCurrentByte];
bool currentBit = bitRead(currentByte, searchROMCurrentBit);
// we missed the falling edge, we emulate one here (this can happen if handling of rising edge interrupt takes too long)
bitStart = now;
if (bit != currentBit)
{
debug.SC_APPEND_STR("Master didn't send our bit, leaving ROM search");
status = OS_WaitReset;
attachInterrupt(InterruptNumber, onewireInterrupt, FALLING);
return;
}
// master released the line, we interpret it as a bit 1 or 0 depending on timing
unsigned long bitLength = now - bitStart;
bitStart = (unsigned long)-1;
searchROMReadingMasterResponseBit = false;
++searchROMCurrentBit;
if (searchROMCurrentBit == 8)
{
++searchROMCurrentByte;
searchROMCurrentBit = 0;
debug.SC_APPEND_STR("sent another ROM byte");
}
if (bitLength < BitZeroMinDuration)
if (searchROMCurrentByte == 8)
{
// received bit = 1
//debug.SC_APPEND_STR_TIME("received bit 1", now);
return 1;
searchROMCurrentByte = 0;
status = OS_WaitReset;
debug.SC_APPEND_STR("ROM sent entirely");
attachInterrupt(InterruptNumber, onewireInterrupt, FALLING);
return;
}
else if (bitLength < BitZeroMaxDuration)
}
else
{
byte currentByte = owROM[searchROMCurrentByte];
bool currentBit = bitRead(currentByte, searchROMCurrentBit);
//bool currentBit = 0;
bool bitToSend = searchROMSendingInverse ? !currentBit : currentBit;
sendBit(bitToSend);
/*if (bitToSend)
debug.SC_APPEND_STR("sent ROM search bit : 1");
else
debug.SC_APPEND_STR("sent ROM search bit : 0");*/
if (searchROMSendingInverse)
{
// received bit = 0
//debug.SC_APPEND_STR_TIME("received bit 0", now);
return 0;
searchROMSendingInverse = false;
searchROMReadingMasterResponseBit = true;
}
else
{
// this is not a valid bit
owError("Invalid read timing");
return InvalidBit;
searchROMSendingInverse = true;
}
}
}
bool readBit()
{
delayMicroseconds(ReadBitSamplingTime);
return owPin.read();
}
void sendBit(bool bit)
{
if (!bit)
if (bit)
{
delayMicroseconds(SendBitDuration);
}
else
{
owPullLow();
delayMicroseconds(SendBitDuration);
owRelease();
ignoreNextFallingEdge = true;
}
}
@ -328,7 +315,6 @@ void beginPresence()
{
unsigned long now = micros();
owPullLow();
owOutTestPin.writeLow();
setTimerEvent(PresenceDuration, &endPresence);
debug.SC_APPEND_STR_TIME("reset", lastReset);
debug.SC_APPEND_STR_TIME("beginPresence", now);
@ -340,7 +326,10 @@ void endPresence()
owRelease();
debug.SC_APPEND_STR_TIME("endPresence", now);
status = OS_AfterPresence;
status = OS_WaitCommand;
receivingByte = 0;
receivingBitPos = 0;
bitStart = (unsigned long)-1;
}
ISR(TIMER1_COMPA_vect) // timer1 interrupt

Write Preview
Loading…
Cancel
Save