From 178835c160940772341615dab7a239c45a875807 Mon Sep 17 00:00:00 2001
From: Daniel Friesel <derf@finalrewind.org>
Date: Tue, 7 Aug 2018 17:31:59 +0200
Subject: Add AM2320 driver

---
 src/driver/am2320.cc | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 src/driver/am2320.cc

(limited to 'src/driver/am2320.cc')

diff --git a/src/driver/am2320.cc b/src/driver/am2320.cc
new file mode 100644
index 0000000..25e2ffe
--- /dev/null
+++ b/src/driver/am2320.cc
@@ -0,0 +1,61 @@
+#include "driver/am2320.h"
+#if defined(MULTIPASS_ARCH_HAS_I2C) && !defined(DRIVER_SOFTI2C)
+#include "driver/i2c.h"
+#else
+#include "driver/soft_i2c.h"
+#endif
+#include "arch.h"
+
+void AM2320::read()
+{
+	txbuf[0] = 0;
+	i2c.xmit(address, 1, txbuf, 0, rxbuf);
+	arch.delay_ms(1);
+	txbuf[0] = 3;
+	txbuf[1] = 0;
+	txbuf[2] = 4;
+	rxbuf[3] = rxbuf[4] = rxbuf[5] = rxbuf[6] = 0;
+	i2c.xmit(address, 3, txbuf, 0, rxbuf);
+	arch.delay_ms(3);
+	i2c.xmit(address, 0, txbuf, 8, rxbuf);
+}
+
+unsigned char AM2320::getStatus()
+{
+	if (rxbuf[0] != 3) {
+		return 1;
+	}
+	if (rxbuf[1] != 4) {
+		return 2;
+	}
+	unsigned short checksum = 0xffff;
+	for (unsigned char i = 0; i < 6; i++) {
+		checksum ^= rxbuf[i] & 0x00ff;
+		for (unsigned char j = 0; j < 8; j++) {
+			if (checksum & 0x0001) {
+				checksum = (checksum >> 1) ^ 0xa001;
+			} else {
+				checksum >>= 1;
+			}
+		}
+	}
+	if ((rxbuf[6] != (checksum & 0x00ff)) || (rxbuf[7] != (checksum >> 8) & 0x00ff)) {
+		return 3;
+	}
+	return 0;
+}
+
+float AM2320::getTemp()
+{
+	if (txbuf[5] & 0x80) {
+		return (-256 * (rxbuf[4] & 0x7f) + rxbuf[5]) / 10.;
+	}
+	return (256 * rxbuf[4] + rxbuf[5]) / 10.;
+}
+
+float AM2320::getHumidity()
+{
+	return (rxbuf[2] * 256 + rxbuf[3]) / 10.;
+}
+
+AM2320 am2320(0x5c);
-- 
cgit v1.2.3