add sc7a20 driver.

Author: wemos

micropython/drivers/sensor/sc7a20/manifest.py

@@ -0,0 +1 @@
+module("sc7a20.py", opt=3)

micropython/drivers/sensor/sc7a20/sc7a20.py

@@ -0,0 +1,51 @@
+# SC7A20 driver for MicroPython on ESP8266/ESP32
+# MIT license; Copyright (c) 2022 WEMOS.CC
+
+from micropython import const
+
+
+WHO_AM_I_REG = const(0x0F)
+CTRL_REG1 = const(0x20)
+CTRL_REG2 = const(0x21)
+CTRL_REG3 = const(0x22)
+ADDR_STATUS_REG = const(0x27)
+OUT_X_L_REG = const(0x28)
+OUT_X_H_REG = const(0x29)
+OUT_Y_L_REG = const(0x2A)
+OUT_Y_H_REG = const(0x2B)
+OUT_Z_L_REG = const(0x2C)
+OUT_Z_H_REG = const(0x2D)
+
+CHIP_ID = const(0x11)
+
+
+class SC7A20:
+    def __init__(self, i2c, address=0x18):
+        self.bus = i2c
+        self.slv_addr = address
+        self.buf = bytearray(6)
+        self.bus.writeto_mem(self.slv_addr, CTRL_REG1, b"\x27")  # 10hz
+
+    def _12bitComplement(self, msb, lsb):
+        # temp=0x0000
+        temp = msb << 8 | lsb
+        temp = temp >> 4
+        # 只有高12位有效
+        temp = temp & 0x0FFF
+
+        if temp & 0x0800:  # 负数 补码==>原码
+            temp = temp & 0x07FF  # 屏弊最高位
+            temp = ~temp
+            temp = temp + 1
+            temp = temp & 0x07FF
+            temp = -temp  # 还原最高位
+
+        return temp
+
+    def measure(self):
+
+        self.buf = self.bus.readfrom_mem(self.slv_addr, OUT_X_L_REG, 6)
+        accel_X = self._12bitComplement(self.buf[1], self.buf[0])
+        accel_Y = self._12bitComplement(self.buf[3], self.buf[2])
+        accel_Z = self._12bitComplement(self.buf[5], self.buf[4])
+        return accel_X, accel_Y, accel_Z