查看“Extend:bitⅡ”的源代码

[[文件:拓展板1.jpg|400px|缩略图|右]]<br />

== 概述 ==
microbit拓展板，支持4路电机驱动、4路舵机驱动。内置声音传感器、光线传感器、无源蜂鸣器、3颗级联全彩RGB灯珠。

== 技术参数 ==
* DC接口：Micro USB 可循环充电
* 采用18650锂电池
* PCI插槽，可接入micro:bit作为主控
* 支持4路舵机驱动和4路电机驱动，采用I2C通讯不占用引脚资源
* 拓展microbit引脚P0/1/2/5/8/11、I2C、UART
* 级联3颗全彩RGB灯珠ws2812
* 内置光线、声音传感器、无源蜂鸣器
* 最大负载电流：1.2A



== 引脚定义 ==
{| class="wikitable"
|-
!  内置  !! micro:bit引脚
|-
| 无源蜂鸣器 || P0
|-
| 光线传感器 || P1
|-
| 声音传感器 || P2
|-
| 全彩RGB灯 || P16
|-
| 电机舵机驱动 || I2C
|-
| UART || RXI->P14<br /> TXO->P15
|}


注意：如要拓展使用P0/P1/P2，要取下跳线帽断开蜂鸣器、光线、声音传感器与microbit连接！

== 快速入门 ==
<big>Step1.</big>[http://wiki.labplus.cn/index.php?title=Micro:bit%E7%BC%96%E7%A8%8B%E5%BF%AB%E9%80%9F%E5%85%A5%E9%97%A8 教程：microbit怎么编程下载？]<br />
<big>Step2.</big>电机驱动：extend:bitⅡ插上micro:bit，接上马达。M1/M2/M3/M4,4路电机驱动，调速0~255<br />
[[文件:Extendbit 电机驱动.png|400px|无框|左]]<br /><br /><br />
<big>Step3.</big>舵机驱动：S1/S2/S3/S4,4路舵机驱动；角度0~180；<br />

[[文件:Extendbit2 舵机.png|300px|无框|左]]<br /><br /><br />
<big>Step4.</big>蜂鸣器：''在使用时蜂鸣器跳线帽须接上''<br />
[[文件:蜂鸣器 extendbit2.png|300px|无框|左]]<br /><br /><br />
<big>Step5.</big>RGB灯：3个串联灯珠，使用P16引脚控制
{| style=" background-color:#ffffcc;" cellpadding="0"
| <small>注意灯珠启始是从"0"开始的</small>
|} 
[[文件:Extendbit2 RGB.png|500px|无框|左]]<br /><br /><br /><br /><br /><br /><br /><br /><br />
<big>Step6.</big>光线、声音传感器：光线使用P1，声音使用P2''在使用时光线、声音跳线帽须接上''
[[文件:Extendbit soundlight.png|230px|无框|左]]<br /><br /><br /><br />
<big>Step7.</big>P0/P1/P2/P5/P8/P11拓展引脚使用，''注意在使用时候，当用到P0/P1/P2，需要取下对应引脚的跳线帽，断开extendbit与microbit的引脚连接！''
== Python各功能测试例程 ==
<small>示例测试各模块功能：<br />
1.上电蜂鸣器发出1KHz，持续1秒声音<br />
2.RGB灯依次红绿蓝显示<br />
3.串口打印输出声音和光线采样数据<br />
4.4路电机驱动正反转和4路舵机180度摆动，间隔1秒<br />
</small>
<pre style="color:blue">
from microbit import *
import music
import neopixel

PCA9685_ADDRESS = 0x41   #device address

#define register
MODE1 = 0x00
MODE2 = 0x01
SUBADR1 = 0x02
SUBADR2 = 0x03
SUBADR3 = 0x04
PRESCALE = 0xFE
LED0_ON_L = 0x06
LED0_ON_H = 0x07
LED0_OFF_L = 0x08
LED0_OFF_H = 0x09
ALL_LED_ON_L = 0xFA
ALL_LED_ON_H = 0xFB
ALL_LED_OFF_L = 0xFC
ALL_LED_OFF_H = 0xFD

STP_CHA_L = 2047
STP_CHA_H = 4095
STP_CHB_L = 1
STP_CHB_H = 2047
STP_CHC_L = 1023
STP_CHC_H = 3071
STP_CHD_L = 3071
STP_CHD_H = 1023

# Servos define 
S1 = 0x01
S2 = 0x02
S3 = 0x03
S4 = 0x04
# Motors define
M2 = 0x1
M1 = 0x2
M4 = 0x3
M3 = 0x4

# Steppers define
STP_M1 = 0x1
STP_M2 = 0x2
FORWARD = 0
REVERSAL = 1

# device init
def initPCA9685(): 
    i2c.write(PCA9685_ADDRESS, bytearray([MODE1, 0x00]))
    setFreq(50)
    for idx in range(0, 16, 1):
        setPwm(idx, 0 ,0)
    #initialized = true

# function: motorRun()
# @param motor:  M1A, M1B, M2A, M2B
# @param speed1: -255 - 255  0 is stop      
def MotorRun(Motors, speed):
    speed = speed * 16  # map 255 to 4096
    if (speed >= 4096):
        speed = 4095
    if (speed <= -4096):
        speed = -4095
    if (Motors <= 4 and Motors > 0):
        pp = (Motors - 1) * 2
        pn = (Motors - 1) * 2 + 1
        if (speed >= 0):
            setPwm(pp, 0, speed)
            setPwm(pn, 0, 0)
        else :
            setPwm(pp, 0, 0)
            setPwm(pn, 0, -speed)

# function: motorRun()
# @param Servos:  S1, S2, S3, S4
# @param degree:  0-180           
def Servo(Servos, degree):
    # 50hz: 20,000 us
    v_us = (degree * 1800 / 180 + 600)  # 0.6 ~ 2.4ms
    value = int(v_us * 4096 / 20000)
    setPwm(Servos + 7, 0, value)

#set frequency    
def setFreq(freq):
    #Constrain the frequency
    prescaleval = int(25000000/(4096*freq)) - 1
    #prescale = prescaleval;  #Math.Floor(prescaleval + 0.5)
    i2c.write(PCA9685_ADDRESS, bytearray([MODE1]))
    oldmode = i2c.read(PCA9685_ADDRESS, 1)
    newmode = (oldmode[0] & 0x7F) | 0x10  # sleep
    i2c.write(PCA9685_ADDRESS, bytearray([MODE1, newmode])) # go to sleep
    i2c.write(PCA9685_ADDRESS, bytearray([PRESCALE, prescaleval]))  # set the prescaler
    i2c.write(PCA9685_ADDRESS, bytearray([MODE1, oldmode[0]]))
    sleep(4)
    i2c.write(PCA9685_ADDRESS, bytearray([MODE1, oldmode[0] | 0xa1]))
    
# function: setPwm()     
def setPwm(channel, on, off):
    if (channel >= 0 and channel <= 15):
        buf = bytearray([LED0_ON_L + 4 * channel, on & 0xff, (on >> 8) & 0xff, off & 0xff, (off >> 8) & 0xff])
        i2c.write(PCA9685_ADDRESS, buf)

# function: setStepper()
# for 2 phase 4 line step motor
# @param stpMotors : STP_M1, STP_M2
# @param dir: FORWARD REVERSAL
# @param speed: 25 - 200
def setStepper(stpMotors, dir, speed):
    spd = speed
    #print(spd)
    setFreq(spd)
    if (stpMotors == 1): #step motor 1
        if (dir): # forward rotating
            setPwm(0, STP_CHA_L, STP_CHA_H)
            setPwm(1, STP_CHB_L, STP_CHB_H)
            setPwm(2, STP_CHC_L, STP_CHC_H)
            setPwm(3, STP_CHD_L, STP_CHD_H)
        else:  # reversal rotating
            setPwm(3, STP_CHA_L, STP_CHA_H)
            setPwm(2, STP_CHB_L, STP_CHB_H)
            setPwm(1, STP_CHC_L, STP_CHC_H)
            setPwm(0, STP_CHD_L, STP_CHD_H)
    elif (stpMotors == 2): #step motor 2
        if (dir):
            setPwm(4, STP_CHA_L, STP_CHA_H)
            setPwm(5, STP_CHB_L, STP_CHB_H)
            setPwm(6, STP_CHC_L, STP_CHC_H)
            setPwm(7, STP_CHD_L, STP_CHD_H)
        else:
            setPwm(7, STP_CHA_L, STP_CHA_H)
            setPwm(6, STP_CHB_L, STP_CHB_H)
            setPwm(5, STP_CHC_L, STP_CHC_H)
            setPwm(4, STP_CHD_L, STP_CHD_H)

#test code
initPCA9685()
# setStepper(STP_M1, REVERSAL, 80)  # test step motor

np = neopixel.NeoPixel(pin16, 3)

music.pitch(1000,1000)
for i in range(0,3):
    np[i]=(255,0,0)
np.show()
sleep(1000)
for i in range(0,3):
    np[i]=(0,255,0)
np.show()
sleep(1000)
for i in range(0,3):
    np[i]=(0,0,255)
np.show()
sleep(1000)
np.clear()
t =running_time()
flag=0
while True:
    print('light:',pin1.read_analog(),' Sound',pin2.read_analog())
    sleep(20)
    if (running_time() - t) > 2000:
        t = running_time()
        flag= not flag
        if flag:
            MotorRun(M1, 255)
            MotorRun(M2, 255)
            MotorRun(M3, 255)
            MotorRun(M4, 255)
            #servo test
            for i in range(1, 5, 1):
                Servo(i, 180)
        else:
            MotorRun(M1, -255)
            MotorRun(M2, -255)
            MotorRun(M3, -255)
            MotorRun(M4, -255)
            for i in range(1, 5, 1):
                Servo(i, 0)
     </pre>

== 应用案例 ==
* [[Example_1 extend:bitⅡ音量计]]
* [[Example_2 extend:bitⅡ音乐盒]]
* [[Example_3 extend:bitⅡ循迹小车]]
* [[Example_4 extend:bitⅡ变色龙]]
* [[Example_5 extend:bitⅡ植物检测器]]