sigmasternchen/MH-Z-CO2-Sensors
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Introduced status codes as return values.

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This commit is contained in:
Tobias Schürg 2018-07-04 23:20:12 +02:00
parent a66da23b89
commit 7158f63459
2 changed files with 29 additions and 8 deletions
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32
MHZ.cpp
View file

@ -28,6 +28,7 @@ void MHZ::setDebug(boolean enable) {
}
int retryCount = 0;
int MHZ::readCO2UART() {
if (debug) Serial.println("-- read CO2 uart ---");
@ -40,14 +41,20 @@ int MHZ::readCO2UART() {
// clear the buffer
memset(response, 0, 9);
int waited = 0;
while (co2Serial.available() == 0) {
if (debug) Serial.print(".");
delay(5); // wait a short moment to avoid false reading
delay(100); // wait a short moment to avoid false reading
if(waited++ > 10) {
if (debug) Serial.println("No response after 10 seconds");
co2Serial.flush();
return STATUS_NO_RESPONSE;
}
}
if (debug) Serial.println();
// The serial stream can get out of sync. The response starts with 0xff, try to resync.
// TODO: I think this is wrong any only happens during initialization
// TODO: I think this might be wrong any only happens during initialization?
boolean skip = false;
while (co2Serial.available() > 0 && (unsigned char)co2Serial.peek() != 0xFF)
{
@ -63,7 +70,14 @@ int MHZ::readCO2UART() {
if (co2Serial.available() > 0) {
co2Serial.readBytes(response, 9);
int count = co2Serial.readBytes(response, 9);
if (count <9) {
co2Serial.flush();
return STATUS_INCOMPLETE;
}
} else {
co2Serial.flush();
return STATUS_INCOMPLETE;
}
if (debug) {
@ -84,8 +98,9 @@ int MHZ::readCO2UART() {
Serial.println(response[8], HEX);
Serial.print("MHZ: Should be: ");
Serial.println(check, HEX);
temperature = -1; // TODO maybe change to another magic value
return -1;
temperature = STATUS_CHECKSUM_MISMATCH;
co2Serial.flush();
return STATUS_CHECKSUM_MISMATCH;
}
int ppm_uart = 256 * (int)response[2] + response[3];
@ -100,16 +115,17 @@ int MHZ::readCO2UART() {
Serial.println(temperature);
}
// Is always 0 for version b
// Version a: status != 0x40
// Is always 0 for version 14a and 19b
// Version a?: status != 0x40
if (debug || status != 0) {
Serial.print(" ! Status not OK ! ");
Serial.print(" ! Status maybe not OK ! ");
Serial.println(status, HEX);
} else if (debug) {
Serial.print(" Status OK: ");
Serial.println(status, HEX);
}
// co2Serial.flush();
return ppm_uart;
}

5
MHZ.h
View file

@ -17,6 +17,11 @@
#define MHZ19B 19
#define STATUS_NO_RESPONSE -2
#define STATUS_CHECKSUM_MISMATCH -3
#define STATUS_INCOMPLETE -4
#include <SoftwareSerial.h>