1 files changed, 113 insertions, 0 deletions
diff --git a/src/driver/sen66.cc b/src/driver/sen66.cc
new file mode 100644
index 0000000..6b12e67
--- /dev/null
+++ b/src/driver/sen66.cc
@@ -0,0 +1,113 @@
+/*
+ * Copyright 2025 Birte Kristina Friesel
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+#include "arch.h"
+#include "driver/sen66.h"
+#if defined(CONFIG_meta_driver_hardware_i2c)
+#include "driver/i2c.h"
+#elif defined(CONFIG_driver_softi2c)
+#include "driver/soft_i2c.h"
+#endif
+
+void SEN66::cleanFan()
+{
+	txbuf[0] = 0x56;
+	txbuf[1] = 0x07;
+	i2c.xmit(address, 2, txbuf, 0, rxbuf);
+}
+
+void SEN66::start()
+{
+	txbuf[0] = 0x00;
+	txbuf[1] = 0x21;
+	i2c.xmit(address, 2, txbuf, 0, rxbuf);
+}
+
+void SEN66::stop()
+{
+	txbuf[0] = 0x01;
+	txbuf[1] = 0x04;
+	i2c.xmit(address, 2, txbuf, 0, rxbuf);
+}
+
+bool SEN66::read()
+{
+	txbuf[0] = 0x03;
+	txbuf[1] = 0x00;
+
+	if (i2c.xmit(address, 2, txbuf, 0, rxbuf)) {
+		return false;
+	}
+	arch.delay_ms(20);
+	if (i2c.xmit(address, 0, txbuf, 27, rxbuf)) {
+		return false;
+	}
+
+	if (!crcValid(rxbuf, 27)) {
+		return false;
+	}
+
+	pm1 = (rxbuf[0] << 8) + rxbuf[1];
+	pm2_5 = (rxbuf[3] << 8) + rxbuf[4];
+	pm4 = (rxbuf[6] << 8) + rxbuf[7];
+	pm10 = (rxbuf[9] << 8) + rxbuf[10];
+	humidity = (rxbuf[12] << 8) + rxbuf[13];
+	temperature = (rxbuf[15] << 8) + rxbuf[16];
+	voc = (rxbuf[18] << 8) + rxbuf[19];
+	nox = (rxbuf[21] << 8) + rxbuf[22];
+	co2 = (rxbuf[24] << 8) + rxbuf[25];
+	return true;
+}
+
+bool SEN66::readStatus()
+{
+	txbuf[0] = 0xd2;
+	txbuf[1] = 0x06;
+	if (i2c.xmit(address, 2, txbuf, 0, rxbuf)) {
+		return false;
+	}
+	arch.delay_ms(20);
+	if (i2c.xmit(address, 0, txbuf, 6, rxbuf)) {
+		return false;
+	}
+
+	if (!crcValid(rxbuf, 6)) {
+		return false;
+	}
+
+	fan_speed_warning = rxbuf[1] & 0x20;
+	co2_sensor_error = rxbuf[3] & 0x12;
+	pm_sensor_error = rxbuf[3] & 0x08;
+	gas_sensor_error = rxbuf[4] & 0x80;
+	rht_sensor_error = rxbuf[4] & 0x40;
+	fan_error = rxbuf[4] & 0x10;
+
+	return true;
+}
+
+unsigned char SEN66::crcWord(unsigned char byte1, unsigned char byte2)
+{
+	unsigned char crc = 0xff ^ byte1;
+	for (unsigned char bit = 8; bit > 0; bit--) {
+		crc = (crc << 1) ^ (crc & 0x80 ? 0x31 : 0);
+	}
+	crc ^= byte2;
+	for (unsigned char bit = 8; bit > 0; bit--) {
+		crc = (crc << 1) ^ (crc & 0x80 ? 0x31 : 0);
+	}
+	return crc;
+}
+
+bool SEN66::crcValid(unsigned char* data, unsigned char length)
+{
+	for (unsigned char i = 0; i < length; i += 3) {
+		if (crcWord(data[i], data[i+1]) != data[i+2]) {
+			return false;
+		}
+	}
+	return true;
+}
+
+SEN66 sen66;