@ -1,18 +1,77 @@
# include "OneWireSlave.h" # include "OneWireSlave.h"
OneWireSlave : : OneWireSlave ( byte * rom , byte pinNumber ) # define DEBUG_LOG
# ifdef DEBUG_LOG
# include "SerialChannel.h"
extern SerialChannel debug ;
Pin dbgOutput ( 3 ) ;
# endif
namespace
{
const unsigned long ResetMinDuration = 480 ;
const unsigned long ResetMaxDuration = 900 ;
const unsigned long PresenceWaitDuration = 30 ;
const unsigned long PresenceDuration = 300 ;
//const unsigned long ReadBitSamplingTime = 30;
const unsigned long SendBitDuration = 35 ;
void ( * timerEvent ) ( ) = 0 ;
}
OneWireSlave * OneWireSlave : : inst_ = 0 ;
ISR ( TIMER1_COMPA_vect ) // timer1 interrupt
{ {
TCCR1B = 0 ; // disable clock
void ( * event ) ( ) = timerEvent ;
timerEvent = 0 ;
event ( ) ;
}
OneWireSlave : : OneWireSlave ( byte * rom , byte pinNumber )
: pin_ ( pinNumber )
, resetStart_ ( ( unsigned long ) - 1 )
, lastReset_ ( 0 )
{
inst_ = this ; // we can have only one instance in the current implementation
memcpy ( rom_ , rom , 7 ) ;
rom_ [ 7 ] = crc8_ ( rom_ , 7 ) ;
} }
void OneWireSlave : : enable ( ) void OneWireSlave : : enable ( )
{ {
# ifdef DEBUG_LOG
debug . append ( " Enabling 1-wire library " ) ;
# endif
cli ( ) ; // disable interrupts
pin_ . inputMode ( ) ;
// prepare hardware timer
TCCR1A = 0 ;
TCCR1B = 0 ;
TIMSK1 | = ( 1 < < OCIE1A ) ; // enable timer compare interrupt
tccr1bEnable_ = ( 1 < < WGM12 ) | ( 1 < < CS11 ) | ( 1 < < CS10 ) ; // turn on CTC mode with 64 prescaler
beginWaitReset_ ( ) ;
sei ( ) ; // enable interrupts
} }
void OneWireSlave : : disable ( ) void OneWireSlave : : disable ( )
{ {
# ifdef DEBUG_LOG
debug . append ( " Disabling 1-wire library " ) ;
# endif
cli ( ) ;
disableTimer_ ( ) ;
pin_ . detachInterrupt ( ) ;
releaseBus_ ( ) ;
sei ( ) ;
} }
bool OneWireSlave : : read ( byte & b ) bool OneWireSlave : : read ( byte & b )
@ -29,3 +88,138 @@ void OneWireSlave::write(byte* bytes, short numBytes, void(*complete)(bool error
{ {
} }
byte OneWireSlave : : crc8_ ( byte * data , short numBytes )
{
byte crc = 0 ;
while ( numBytes - - ) {
byte inbyte = * data + + ;
for ( byte i = 8 ; i ; i - - ) {
byte mix = ( crc ^ inbyte ) & 0x01 ;
crc > > = 1 ;
if ( mix ) crc ^ = 0x8C ;
inbyte > > = 1 ;
}
}
return crc ;
}
void OneWireSlave : : setTimerEvent_ ( short delayMicroSeconds , void ( * handler ) ( ) )
{
delayMicroSeconds - = 10 ; // remove overhead (tuned on Arduino Uno)
short skipTicks = ( delayMicroSeconds - 3 ) / 4 ; // round the micro seconds delay to a number of ticks to skip (4us per tick, so 4us must skip 0 tick, 8us must skip 1 tick, etc.)
if ( skipTicks < 1 ) skipTicks = 1 ;
TCNT1 = 0 ;
OCR1A = skipTicks ;
timerEvent = handler ;
TCCR1B = tccr1bEnable_ ;
}
void OneWireSlave : : disableTimer_ ( )
{
TCCR1B = 0 ;
}
void OneWireSlave : : onEnterInterrupt_ ( )
{
dbgOutput . outputMode ( ) ;
dbgOutput . writeLow ( ) ;
}
void OneWireSlave : : onLeaveInterrupt_ ( )
{
dbgOutput . writeHigh ( ) ;
}
void OneWireSlave : : error_ ( const char * message )
{
# ifdef DEBUG_LOG
debug . append ( message ) ;
# endif
beginWaitReset_ ( ) ;
}
void OneWireSlave : : pullLow_ ( )
{
pin_ . outputMode ( ) ;
pin_ . writeLow ( ) ;
}
void OneWireSlave : : releaseBus_ ( )
{
pin_ . inputMode ( ) ;
}
void OneWireSlave : : beginWaitReset_ ( )
{
disableTimer_ ( ) ;
pin_ . attachInterrupt ( & OneWireSlave : : waitResetHandler_ , CHANGE ) ;
resetStart_ = ( unsigned int ) - 1 ;
}
void OneWireSlave : : waitReset_ ( )
{
onEnterInterrupt_ ( ) ;
bool state = pin_ . read ( ) ;
unsigned long now = micros ( ) ;
if ( state )
{
if ( resetStart_ = = ( unsigned int ) - 1 )
{
onLeaveInterrupt_ ( ) ;
return ;
}
unsigned long resetDuration = now - resetStart_ ;
resetStart_ = ( unsigned int ) - 1 ;
if ( resetDuration > = ResetMinDuration )
{
if ( resetDuration > ResetMaxDuration )
{
error_ ( " Reset too long " ) ;
onLeaveInterrupt_ ( ) ;
return ;
}
lastReset_ = now ;
setTimerEvent_ ( PresenceWaitDuration - ( micros ( ) - now ) , & OneWireSlave : : beginPresenceHandler_ ) ;
}
}
else
{
resetStart_ = now ;
}
onLeaveInterrupt_ ( ) ;
}
void OneWireSlave : : beginPresence_ ( )
{
unsigned long now = micros ( ) ;
pullLow_ ( ) ;
setTimerEvent_ ( PresenceDuration , & OneWireSlave : : endPresenceHandler_ ) ;
# ifdef DEBUG_LOG
debug . SC_APPEND_STR_TIME ( " reset " , lastReset_ ) ;
debug . SC_APPEND_STR_TIME ( " beginPresence " , now ) ;
# endif
}
void OneWireSlave : : endPresence_ ( )
{
unsigned long now = micros ( ) ;
releaseBus_ ( ) ;
# ifdef DEBUG_LOG
debug . SC_APPEND_STR_TIME ( " endPresence " , now ) ;
# endif
beginWaitCommand_ ( ) ;
}
void OneWireSlave : : beginWaitCommand_ ( )
{
/*pin_.attachInterrupt(&OneWireSlave::waitCommand_, FALLING);
receivingByte = 0 ;
receivingBitPos = 0 ;
bitStart = ( unsigned long ) - 1 ; */
}
Youen Toupin
10 years ago