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fix negative anwser interpretation

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This commit is contained in:
Michael Doppler 2024-04-29 07:56:42 +00:00
parent d25d0a559a
commit 7eac405ed8
1 changed files with 9 additions and 0 deletions
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9
esphome/components/mcp3428/mcp3428.cpp
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@ -102,6 +102,12 @@ float MCP3428Component::request_measurement(MCP3428Multiplexer multiplexer, MCP3
} }
// got valid measurement, clean up unused bits from the anwser code and prepare tick size // got valid measurement, clean up unused bits from the anwser code and prepare tick size
bool negative = false;
if (anwser[0] & 0b10000000 != 0) {
// negative number, clean up bit and mark as negative
negative = true;
anwser[0] &= 0b01111111;
}
float tick_voltage = 2.048f / 32768; // ref voltage 2.048V/non-sign bits, default 15 bits float tick_voltage = 2.048f / 32768; // ref voltage 2.048V/non-sign bits, default 15 bits
switch (resolution) { switch (resolution) {
case MCP3428Resolution::MCP3428_12_BITS: case MCP3428Resolution::MCP3428_12_BITS:
@ -132,6 +138,9 @@ float MCP3428Component::request_measurement(MCP3428Multiplexer multiplexer, MCP3
} }
// convert code (first 2 bytes of cleaned up anwser) into voltage ticks // convert code (first 2 bytes of cleaned up anwser) into voltage ticks
int16_t ticks = anwser[0] << 8 | anwser[1]; int16_t ticks = anwser[0] << 8 | anwser[1];
if (negative) {
ticks *= (-1);
}
this->status_clear_warning(); this->status_clear_warning();
return tick_voltage * ticks; return tick_voltage * ticks;