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Fix handling of large messages (when multiple Serial.readBytes call need to get a message through the serial line) #98

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Fix handling of large messages (when multiple Serial.readBytes call need to get a message through the serial line) #98

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98 changes: 59 additions & 39 deletions p1reader.h
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Original file line number Diff line number Diff line change
@@ -1,27 +1,41 @@
//-------------------------------------------------------------------------------------
// ESPHome P1 Electricity Meter custom sensor
// Copyright 2020 Pär Svanström
//
//
// History
// 0.1.0 2020-11-05: Initial release
// 0.x.0 2023-04-18: Added HDLC support
// 0.x.1 2024-06-18: Fix receiving large messages
//
// When the smartmeter sends large messages (>1KB) these will not fit
// in a single buffer, will not be availble for reading in one go.
// This will cause CRC errors.
//
// Reorganized steps. Moved buffer cleanup after the last line is
// received (line starting with !).
// Moved creating new ParsedMessages out of the reading loop.
//
// This avoids possibly resetting previously parsed values. Also
// avoids buffer celanup causing bad CRC when large messages (>1KB) are
// coming through the serial line.
//
// MIT License
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//-------------------------------------------------------------------------------------

#include "esphome.h"

#define BUF_SIZE 60
//#define BUF_SIZE 60
#define BUF_SIZE 8192

class ParsedMessage {
public:
Expand Down Expand Up @@ -71,7 +85,7 @@ class P1Reader : public Component, public UARTDevice {
const char* DATA_ID = "1-0";

protected:
char buffer[BUF_SIZE];
char buffer[BUF_SIZE+2];

public:
Sensor *cumulativeActiveImport = new Sensor();
Expand Down Expand Up @@ -257,15 +271,15 @@ class P1Reader : public Component, public UARTDevice {
}

private:
uint16_t crc = 0x0000;
ParsedMessage parsed = ParsedMessage();
bool telegramEnded = false;
int len=0;

void readP1Message() {
if (available()) {
uint16_t crc = 0x0000;
ParsedMessage parsed = ParsedMessage();
bool telegramEnded = false;

while (available()) {
int len = Serial.readBytesUntil('\n', buffer, BUF_SIZE);

len = Serial.readBytesUntil('\n', buffer, BUF_SIZE);
if (len > 0) {
ESP_LOGD("data", "%s", buffer);

Expand All @@ -281,9 +295,20 @@ class P1Reader : public Component, public UARTDevice {
ESP_LOGI("crc", "Telegram read. CRC: %04X = %04X. PASS = %s", crc, crcFromMsg, parsed.crcOk ? "YES": "NO");
telegramEnded = true;

// if the CRC pass, publish sensor values
if (parsed.crcOk) {
publishSensors(&parsed);
}

// clean up...
parsed = ParsedMessage();
crc = 0x0000;
memset(buffer, 0, BUF_SIZE - 1);
telegramEnded = false;

// otherwise pass the row through the CRC calculation
} else {
for (int i = 0; i < len + 1; i++) {
for (int i = 0; i < len + 1 ; i++) {
crc = crc16_update(crc, buffer[i]);
}
}
Expand All @@ -301,23 +326,18 @@ class P1Reader : public Component, public UARTDevice {
}
}
}
// clean buffer
memset(buffer, 0, BUF_SIZE - 1);

if (!telegramEnded && !available()) {
// wait for more data
delay(40);
}
}

// if the CRC pass, publish sensor values
if (parsed.crcOk) {
publishSensors(&parsed);
//if (!telegramEnded && !available()) {
// wait for more data
// delay(40);
//
//}
}

}
}


};

class P1ReaderHDLC : public P1Reader {
Expand Down Expand Up @@ -354,7 +374,7 @@ class P1ReaderHDLC : public P1Reader {
ESP_LOGE("hdlc", "Unexpected tag %X in struct, bailing out", tag);
return false;
}

uint8_t str_length = read();
if(Serial.readBytes(buffer, str_length) != str_length) {
ESP_LOGE("hdlc", "Unable to read %d bytes of OBIS code", str_length);
Expand Down Expand Up @@ -384,14 +404,14 @@ class P1ReaderHDLC : public P1Reader {
uvalue = buffer[3] | buffer[2] << 8 | buffer[1] << 16 | buffer[0] << 24;
//ESP_LOGD("hdlc", "Value of uvalue is %u", uvalue);
} else if (tag == 0x10) {
Serial.readBytes(buffer, 2);
//value = buffer[0] | buffer[1] << 8; //
Serial.readBytes(buffer, 2);
//value = buffer[0] | buffer[1] << 8; //
is_signed = true;
value = buffer[1] | buffer[0] << 8;
//ESP_LOGD("hdlc", "(Signed) Value of value is %d", value);
} else if (tag == 0x12) {
Serial.readBytes(buffer, 2);
//uvalue = buffer[0] | buffer[1] << 8; //
Serial.readBytes(buffer, 2);
//uvalue = buffer[0] | buffer[1] << 8; //
uvalue = buffer[1] | buffer[0] << 8;
//ESP_LOGD("hdlc", "(Unsigned) Value of uvalue is %u", uvalue);
} else {
Expand All @@ -412,24 +432,24 @@ class P1ReaderHDLC : public P1Reader {

double scaled_value = pow(10, scaler) * value;

// Volt and Ampere are the only two units where p1reader.yaml doesn't specify
// Volt and Ampere are the only two units where p1reader.yaml doesn't specify
// we should report in 1/1000, all others should be divided.
if(unit != 33 && unit != 35)
scaled_value = scaled_value / 1000;

snprintf(value_buf, 24, "%f", scaled_value);
parseRow(parsed, obis, value_buf);
}




return true;
}

/* Reads messages formatted according to "Branschrekommendation v1.2", which
at the time of writing (20210207) is used by Tekniska Verken's Aidon 6442SE
meters. This is a binary format, with a HDLC Frame.
meters. This is a binary format, with a HDLC Frame.

This code is in no way a generic HDLC Frame parser, but it does the job
of decoding this particular data stream.
Expand Down Expand Up @@ -475,7 +495,7 @@ class P1ReaderHDLC : public P1Reader {
parseHDLCState = OUTSIDE_FRAME;
return;
}
// ESP_LOGD("hdlc", "Got %d HDLC bytes, now reading 4 Invoke ID And Priority bytes", len);
// ESP_LOGD("hdlc", "Got %d HDLC bytes, now reading 4 Invoke ID And Priority bytes", len);
len = Serial.readBytes(buffer, 4);
if (len != 4 || buffer[0] != 0x40 || buffer[1] != 0x00 || buffer[2] != 0x00 || buffer[3] != 0x00)
{
Expand All @@ -489,7 +509,7 @@ class P1ReaderHDLC : public P1Reader {
//ESP_LOGD("hdlc", "Length of datetime field is %d", data);
Serial.readBytes(buffer, data);

data = read();
data = read();
ESP_LOGD("hdlc", "Expect 0x01 (array tag), got 0x%02x", data);
if(data != 0x01) {
parseHDLCState = OUTSIDE_FRAME;
Expand Down Expand Up @@ -522,4 +542,4 @@ class P1ReaderHDLC : public P1Reader {
}
}
}
};
};