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[mcp3204] Read a conversion in one SPI transaction (#19423)

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Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
Co-authored-by: pre-commit-ci-lite[bot] <117423508+pre-commit-ci-lite[bot]@users.noreply.github.com>
Co-authored-by: J. Nick Koston <nick@koston.org>
Co-authored-by: J. Nick Koston <nick@home-assistant.io>
This commit is contained in:
oxynatOr
2026-09-24 14:06:07 -04:00
committed by GitHub
co-authored by Claude Opus 5 pre-commit-ci-lite[bot] J. Nick Koston J. Nick Koston
parent 16757a84e6
commit 057bf88e4a
1 changed files with 8 additions and 9 deletions
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esphome/components/mcp3204/mcp3204.cpp
+8 -9
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@@ -18,19 +18,18 @@ void MCP3204::dump_config() {
}
float MCP3204::read_data(uint8_t pin, bool differential) {
uint8_t command, b0, b1;
command = (1 << 6) | // start bit
((differential ? 0 : 1) << 5) | // single or differential bit
((pin & 0x07) << 2); // pin
const uint8_t command = (1 << 6) | // start bit
((differential ? 0 : 1) << 5) | // single or differential bit
((pin & 0x07) << 2); // pin
// One full-duplex transaction: command out, 12-bit result back in bytes 1 and 2.
// Word aligned so ESP-IDF DMA uses the buffer in place; only ESP32-P4 also checks the length and bounces.
alignas(4) uint8_t buffer[3] = {command, 0x00, 0x00};
this->enable();
this->transfer_byte(command);
b0 = this->transfer_byte(0x00);
b1 = this->transfer_byte(0x00);
this->transfer_array(buffer, sizeof(buffer));
this->disable();
uint16_t digital_value = encode_uint16(b0, b1) >> 4;
uint16_t digital_value = encode_uint16(buffer[1], buffer[2]) >> 4;
return float(digital_value) / 4096.000f * this->reference_voltage_; // in V
}