Add GroveAHT20

2021-01-31 11:45:51 +09:00
parent f55133bc27
commit 1548cd4b9c
4 changed files with 166 additions and 3 deletions
--- a/sensors/AHT20.ts
+++ b/sensors/AHT20.ts
@ -0,0 +1,87 @@
+namespace grove
+{
+    export namespace sensors
+    {
+
+        export class AHT20
+        {
+            public constructor(address: number = 0x38)
+            {
+                this._Address = address;
+            }
+
+            public Initialization(): AHT20
+            {
+                const buf = pins.createBuffer(3);
+                buf[0] = 0xbe;
+                buf[1] = 0x08;
+                buf[2] = 0x00;
+                pins.i2cWriteBuffer(this._Address, buf, false);
+                basic.pause(10);
+
+                return this;
+            }
+
+            public TriggerMeasurement(): AHT20
+            {
+                const buf = pins.createBuffer(3);
+                buf[0] = 0xac;
+                buf[1] = 0x33;
+                buf[2] = 0x00;
+                pins.i2cWriteBuffer(this._Address, buf, false);
+                basic.pause(80);
+
+                return this;
+            }
+
+            public GetState(): { Busy: boolean, Calibrated: boolean }
+            {
+                const buf = pins.i2cReadBuffer(this._Address, 1, false);
+                const busy = buf[0] & 0x80 ? true : false;
+                const calibrated = buf[0] & 0x08 ? true : false;
+
+                return { Busy: busy, Calibrated: calibrated };
+            }
+
+            public Read(): { Humidity: number, Temperature: number }
+            {
+                const buf = pins.i2cReadBuffer(this._Address, 7, false);
+
+                const crc8 = AHT20.CalcCRC8(buf, 0, 6);
+                if (buf[6] != crc8) return null;
+
+                const humidity = ((buf[1] << 12) + (buf[2] << 4) + (buf[3] >> 4)) * 100 / 1048576;
+                const temperature = (((buf[3] & 0x0f) << 16) + (buf[4] << 8) + buf[5]) * 200 / 1048576 - 50;
+
+                return { Humidity: humidity, Temperature: temperature };
+            }
+
+            private _Address: number;
+
+            private static CalcCRC8(buf: Buffer, offset: number, size: number): number
+            {
+                let crc8 = 0xff;
+                for (let i = 0; i < size; ++i)
+                {
+                    crc8 ^= buf[offset + i];
+                    for (let j = 0; j < 8; ++j)
+                    {
+                        if (crc8 & 0x80)
+                        {
+                            crc8 <<= 1;
+                            crc8 ^= 0x31;
+                        }
+                        else
+                        {
+                            crc8 <<= 1;
+                        }
+                        crc8 &= 0xff;
+                    }
+                }
+
+                return crc8;
+            }
+
+        }
+    }
+}