## 传感器的使用及I2C总线

### 1. I2C Scan from Maker Pi
[[https://learn.sparkfun.com/tutorials/i2c/all|Sparkfun上关于I2C的介绍]]

<code python>
# This code scans any I2C devices connected to I2C0 at frequency 100kHz
# and print the address(es) on serial.
# ---
# Connection: I2C0, SCL0 = GP1, SDA0 = GP0
# ---
# Hardware: Any RP2040 boards.
# ---
import machine

i2c0 = machine.I2C(0, scl=machine.Pin(1), sda=machine.Pin(0), freq=100000)

devices = i2c0.scan()
if devices:
    for d in devices:
        print("i2c0:")
        print(hex(d))
</code>

I2C scan with printing
<code python>
# This code scans any I2C devices connected to I2C0 & I2C1 at frequency 100kHz
# and print the address(es) on serial.
# ---
# Connection: I2C0, SCL0 = GP1, SDA0 = GP0
#             I2C1, SCL1 = GP3, SDA1 = GP2
# ---
# Hardware: Any RP2040 boards.
# ---
import machine

i2c0 = machine.I2C(0, scl=machine.Pin(1), sda=machine.Pin(0), freq=100000)
i2c1 = machine.I2C(1, scl=machine.Pin(3), sda=machine.Pin(2), freq=100000)

devices = i2c0.scan()
if devices:
    for d in devices:
        print("i2c0:")
        print(hex(d))
        
devices = i2c1.scan()
if devices:
    for d in devices:
        print("\ni2c1:")
        print(hex(d))
</code>

### 2. MMA7660的驱动程序库


<code python>
# from machine import I2C
class MMA7660_DATA:
    def __init__(self):
        self.X = None
        self.Y = None
        self.Z = None
        self.TILT = None
        self.SRST = None
        self.SPCNT = None
        self.INTSU = None
        self.MODE = None
        self.SR = None
        self.PDET = None
        self.PD = None
# class MMA7660_ACC_DATA:
#     def __init__(self,x,y,z):
#         self.x = x
#         self.y = y
#         self.z = z
class MMA7660_LOOKUP(object):
    def __init__(self):
        self.g = None
        self.xyAngle = None
        self.zAngle = None
class Accelerometer(object):
    MMA7660_ADDR = 0x4c
    MMA7660TIMEOUT = 500
    MMA7660_X = 0x00
    MMA7660_Y = 0x01
    MMA7660_Z = 0x02
    MMA7660_TILT = 0x03
    MMA7660_SRST = 0x04
    MMA7660_SPCNT = 0x05
    MMA7660_INTSU = 0x06
    MMA7660_SHINTX = 0x80
    MMA7660_SHINTY = 0x40
    MMA7660_SHINTZ = 0x20
    MMA7660_GINT = 0x10
    MMA7660_ASINT = 0x08
    MMA7660_PDINT = 0x04
    MMA7660_PLINT = 0x02
    MMA7660_FBINT = 0x01
    MMA7660_MODE = 0x07
    MMA7660_STAND_BY = 0x00
    MMA7660_ACTIVE = 0x01
    MMA7660_SR = 0x08      # sample rate register
    AUTO_SLEEP_120 = 0X00     # 120 sample per second
    AUTO_SLEEP_64 = 0X01
    AUTO_SLEEP_32 = 0X02
    AUTO_SLEEP_16 = 0X03
    AUTO_SLEEP_8  = 0X04
    AUTO_SLEEP_4  = 0X05
    AUTO_SLEEP_2  = 0X06
    AUTO_SLEEP_1  = 0X07
    MMA7660_PDET = 0x09
    MMA7660_PD = 0x0A
    accLookup = []
    for i in range(64):
        s = MMA7660_LOOKUP()
        accLookup.insert(i,s)
    def __init__(self, i2c, address, interrupts=False):
        self.i2c = i2c
        self.address = address
        i2c.init(I2C.MASTER, baudrate=20000)
        initAccelTable()
        setMode(MMA7660_STAND_BY)
        setSampleRate(AUTO_SLEEP_32)
        if interrupts:
            write(MMA7660_INTSU, interrupts)
        setMode(MMA7660_ACTIVE)
    def write(self, register, data):
        register = bytearray([register])
        data = bytearray([data])
        self.i2c.writeto_mem(self.address, register, data)
    def read(self, register):
        register = bytearray([register])
        data = bytearray([data])
        buf = ''
        i2c.readfrom_mem_into(self.address,register,buf)
        return buf
    def initAccelTable(self):
        val = 0
        for i in range(32):
            accLookup[i].g = val
            val += 0.047
        val = -0.047
        for i in range(63,31,-1):
            accLookup[i].g = val
            val -= 0.047
        val = 0
        valZ = 90
        for i in range(22):
            accLookup[i].xyAngle = val
            accLookup[i].zAngle = valZ
            val -= 2.69
            valZ += 2.69
        val = -2.69
        valZ = -87.31
        for i in range(63, 42,-1):
            accLookup[i].xyAngle = val
            accLookup[i].zAngle = valZ
            val -= 2.69
            valZ += 2.69
        for i in range(22,43):
            accLookup[i].xyAngle = 255
            accLookup[i].zAngle = 255
    def setMode(self, mode):
        write(MMA7660_MODE,mode)
    def setSampleRate(self):
        write(MMA7660_SR,rate)
    def getXYZ(self, x, y, z):
		count = 0
		val = [64,64,64]
        i2c.readfrom(self.address,1)
        i2c.readfrom(self.address,3)
        return data = (x,y,z)
    def getAcceleration(self):
        return True
        return False
    def getAllData(self):
        count = 0
        return True
        return False
</code>

### 3. Maker.io上的文章

[[https://www.digikey.com/en/maker/projects/raspberry-pi-pico-and-rp2040-micropython-part-2-i2c-sensor-and-module/b43e7958153f41fc9e7403df4d626ba5|I2C传感器和模块]]