docs: Fix ENV pressure unit and add I2C guide.

Signed-off-by: luoweiyuan <luoweiyuan@m5stack.com>
(cherry picked from commit 38560cb728be6c652f6a976ac4f549f1e80c17f7)

Author: luoweiyuan

docs/source/hardware/i2c.rst

@@ -0,0 +1,81 @@
+I2C
+===
+
+I2C implements a two-wire serial bus using an SDA data line and an SCL clock line.
+Use it to communicate with Unit, Hat, and other I2C peripherals.
+
+MicroPython Example
+-------------------
+
+Scan PORT.A on a CoreS3 or most S3-based controllers.
+
+.. code-block:: python
+
+    from hardware import I2C, Pin
+
+    i2c0 = I2C(0, scl=Pin(1), sda=Pin(2), freq=100000)
+    print(i2c0.scan())
+
+Scan PORT.A on Tough.
+
+.. code-block:: python
+
+    from hardware import I2C, Pin
+
+    i2c0 = I2C(0, scl=Pin(33), sda=Pin(32), freq=100000)
+    print(i2c0.scan())
+
+**API**
+-------
+
+class I2C
+^^^^^^^^^
+
+.. _hardware.I2C:
+
+.. class:: I2C(id, *, scl, sda, freq=400000)
+
+    Construct an I2C bus object.
+
+    :param int id: I2C peripheral id.
+    :keyword scl: SCL clock pin.
+    :type scl: Pin or int
+    :keyword sda: SDA data pin.
+    :type sda: Pin or int
+    :keyword int freq: I2C bus frequency in Hz.
+
+    MicroPython Code Block:
+
+        .. code-block:: python
+
+            from hardware import I2C, Pin
+
+            i2c0 = I2C(0, scl=Pin(1), sda=Pin(2), freq=100000)
+
+    .. method:: I2C.scan()
+
+        Scan all I2C addresses between 0x08 and 0x77 and return a list of responding addresses.
+
+        MicroPython Code Block:
+
+            .. code-block:: python
+
+                print(i2c0.scan())
+
+    .. method:: I2C.readfrom_mem(addr, memaddr, nbytes, *, addrsize=8)
+
+        Read ``nbytes`` from a device register.
+
+        :param int addr: I2C device address.
+        :param int memaddr: register address.
+        :param int nbytes: number of bytes to read.
+        :keyword int addrsize: register address size in bits.
+
+    .. method:: I2C.writeto_mem(addr, memaddr, buf, *, addrsize=8)
+
+        Write ``buf`` to a device register.
+
+        :param int addr: I2C device address.
+        :param int memaddr: register address.
+        :param bytes buf: bytes-like object to write.
+        :keyword int addrsize: register address size in bits.

docs/source/hardware/index.rst

@@ -10,6 +10,7 @@ Hardware
     can.rst
     display.rst
     imu.rst
+    i2c.rst
     ir.rst
     lora.rst
     mic.rst

docs/source/hat/env.rst

@@ -56,7 +56,7 @@ Methods
 
 .. method:: ENVHat.read_temperature()
 
-    This method allows to read the temperature value collected by ENV and returns a floating point value. The hat of measurement is °C.
+    This method allows to read the temperature value collected by ENV and returns a floating point value. The unit of measurement is °C.
 
     UIFLOW2:
 
@@ -65,7 +65,7 @@ Methods
 
 .. method:: ENVHat.read_humidity()
 
-    This method allows to read the relative humidity value collected by ENV and returns a floating point value. The hat of measurement is %RH.
+    This method allows to read the relative humidity value collected by ENV and returns a floating point value. The unit of measurement is %RH.
 
     UIFLOW2:
 
@@ -74,7 +74,7 @@ Methods
 
 .. method:: ENVHat.read_pressure()
 
-    This method allows to read the atmospheric pressure collected by ENV and returns a floating point value. The hat of measurement is Pa.
+    This method allows to read the atmospheric pressure collected by ENV and returns a floating point value. The unit of measurement is hPa.
 
     UIFLOW2:
 

docs/source/unit/env.rst

@@ -14,12 +14,17 @@ Micropython Example::
 
     import M5
     from M5 import *
+    from hardware import I2C, Pin
     from unit import *
 
     M5.begin()
 
+    # PORT.A on CoreS3 and most S3-based controllers.
     i2c0 = I2C(0, scl=Pin(1), sda=Pin(2), freq=100000)
 
+    # PORT.A on Tough.
+    # i2c0 = I2C(0, scl=Pin(33), sda=Pin(32), freq=100000)
+
     env_0 = ENVUnit(i2c=i2c0, type=1) # ENVUnit
     env2_0 = ENVUnit(i2c=i2c0, type=2) # ENVUnit II
     env3_0 = ENVUnit(i2c=i2c0, type=3) # ENVUnit III
@@ -85,7 +90,7 @@ Methods
 
 .. method:: ENVUnit.read_pressure()
 
-    This method allows to read the atmospheric pressure collected by ENV and returns a floating point value. The unit of measurement is Pa.
+    This method allows to read the atmospheric pressure collected by ENV and returns a floating point value. The unit of measurement is hPa.
 
     UIFLOW2: