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Added serial reads to flush spurious output from sensor #3

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Added serial reads to flush spurious output from sensor #3

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989cb87
Added serial reads to flush spurious output from sensor
gitpeut Feb 5, 2024
7089d10
RX_flush
gitpeut Feb 8, 2024
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33 changes: 31 additions & 2 deletions SD_ZH03B.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -162,6 +162,14 @@ bool SD_ZH03B::readData(void) {
return true;
}

int SD_ZH03B::RX_flush(void){
delay(100);
int spurious_count;
for(spurious_count = 0; _serial.available(); ++spurious_count ) {
_serial.read();
}
return spurious_count;
}

void SD_ZH03B::setMode( const mode_t _mode ) {
switch( _mode ) {
Expand All @@ -180,6 +188,8 @@ void SD_ZH03B::setQandAmode(void) {
_currentMode = QA_MODE;
_sizeFrame = SIZEOF_QA_FRAME;
_sendCmd( 0x78, 0x41, 0x46 );

RX_flush();
}


Expand All @@ -192,6 +202,8 @@ void SD_ZH03B::setInitiativeMode(void) { // default mode
_sizeFrame = ZH06_SIZEOF_IU_FRAME;

_sendCmd( 0x78, 0x40, 0x47 );

RX_flush();
}


Expand All @@ -215,15 +227,32 @@ bool SD_ZH03B::_getCmdConfirmation(void) {

_serial.readBytes( _unionFrame.buffer, 9 ); // read the response to a buffer

#ifdef DEBUG
Serial.println("Command confirmation");
for( uint8_t i = 0; i < 9; i++ ) {
Serial.print( _unionFrame.buffer[i], HEX); Serial.print( ":");
}
Serial.println();
#endif

// check up the received response
if( _unionFrame.buffer[1] == 0xA7 && _unionFrame.buffer[2] == 0x01 && _unionFrame.buffer[8] == 0x58 )
if( _unionFrame.buffer[1] == 0xA7 && _unionFrame.buffer[2] == 0x01 && _unionFrame.buffer[8] == 0x58 ){
return true;

}

Serial.println("Command confirmation invalid:");
for( uint8_t i = 0; i < 9; i++ ) {
Serial.print( _unionFrame.buffer[i], HEX); Serial.print( ":");
}
Serial.println();

return false;
}

void SD_ZH03B::_sendCmd(const uint8_t ch1, const uint8_t ch2, const uint8_t ch3) {

_serial.flush(); // clear buffer
RX_flush();

// send command header
_serial.write((uint8_t)0xFF);
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7 changes: 7 additions & 0 deletions SD_ZH03B.h
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Original file line number Diff line number Diff line change
Expand Up @@ -139,6 +139,13 @@ enum type_t : uint8_t {
uint16_t getPM10_0(void) const {
return _currentMode == IU_MODE ? _unionFrame.ZH03_IUframe.concPM10_0 : _unionFrame.ZHxx_QAframe.concPM10_0;
}

/**
* @brief read spurious data on RX before sending
* @note unpredicatble a sensor may havesent spurious data,which can confuse later data reads
* @return nunmber of spurious bytes read */

int RX_flush(void);

#define ZH03_SIZEOF_IU_FRAME 24
#define ZH06_SIZEOF_IU_FRAME 32
Expand Down