端口扩展

概述

当主控的引脚不够用时，可用该模块通过I2C接口拓展I/O口，最大支持8个I/O引脚拓展。

技术参数

• 工作电压：VCC 3.3-5V
• I2C数字信号通讯
• 最大支持8个I/O端口拓展
• 模块尺寸：24x46x7.5mm

引脚定义

VCC	电源
SDA	I2C数据
SCL	I2C时钟
GND	地

使用教程

详细的寄存器操作和指令说明，可查阅芯片手册点击下载

MicroPython示例

from microbit import *

def extIOInit(pin, mode):
    i2c.write(0x20, bytearray([3]))
    mode_old=i2c.read(0x20, 1)
    mode_new = 0
    if mode == 1:
        mode_new = mode_old[0] | (1 << pin)
    elif mode == 0:
        mode_new = mode_old[0] & (~(1 << pin))
    cfg= bytearray([0x03,mode_new])
    i2c.write(0x20, cfg)

def readExtendedIO(pin):
    reg=bytearray([0])
    i2c.write(0x20, reg)
    dat=i2c.read(0x20, 4)
    return (dat[0] >> pin) & 0x01

def writeExtendedIO(pin, output):
    reg=bytearray([1])
    i2c.write(0x20, reg)
    stat_old=i2c.read(0x20, 3)
    stat_new = 0
    if output == 1:
        stat_new = stat_old[0] | (1 << pin)
    elif output == 0:
        stat_new = stat_old[0] & (~(1 << pin))
    cfg = bytearray([0x01, stat_new])
    i2c.write(0x20,cfg)


extIOInit(0,0)  #pin io0 set output mode
extIOInit(1,0)  #pin io1 set output mode
extIOInit(6,1)  #pin io6 set input mode
while True:
    buttonVal = readExtendedIO(6)
    if buttonVal == 0:
        writeExtendedIO(0, 1)
        writeExtendedIO(1, 1)
    elif buttonVal == 1:
        writeExtendedIO(0, 0)
        writeExtendedIO(1, 0)
    sleep(100)

Arduino示例

#include <Wire.h>

void setup()
{
	Wire.begin();
	extIOInit(0, 0);    //设置IO0为输出模式
	extIOInit(1, 1);      //设置IO1为输入模式
}

// Add the main program code into the continuous loop() function
void loop()
{
	
	if (readExtendedIO(1) == 0)
	{
		writeExtendedIO(0, 1);
	}
	else
	{
		writeExtendedIO(0, 1);
	}

}

void extIOInit(byte pin, byte mode)     //设置IO引脚输入输出模式。mode=0，为输出模式，mode=1，为输入模式
{
	byte mode_old;
	Wire.beginTransmission(0x20);
	Wire.write(0x03);
	Wire.endTransmission();
	Wire.requestFrom(0x20, 1);
	while (Wire.available() > 0)
	{
		mode_old = Wire.read();
	}
	byte mode_new = 0;
	if (mode == 1)
	{
		mode_new = mode_old | (1 << pin);
	}
	else if (mode == 0)
	{
		mode_new = mode_old & (~(1 << pin));

	}
	byte cfg[2] = { 0x03, mode_new };
	Wire.beginTransmission(0x20);
	Wire.write(cfg, 2);
	Wire.endTransmission();

}

uint16_t readExtendedIO(byte pin)        //IO读函数
{
	byte dat[4];
	Wire.beginTransmission(0x20);
	Wire.write(0x00);
	Wire.endTransmission();
	Wire.requestFrom(0x20, 4);
	while (Wire.available() > 0)
	{
		Wire.readBytes(dat, 4);
	}
	return (dat[0] >> pin) & 0x01;

}

void writeExtendedIO(byte pin, byte value)    //IO写函数
{
	byte stat_old[3];
	Wire.beginTransmission(0x20);
	Wire.write(0x01);
	Wire.endTransmission();
	Wire.requestFrom(0x20, 3);
	while (Wire.available() > 0)
	{
		Wire.readBytes(stat_old, 3);
	}
	byte stat_new = 0;
	if (value == 1)
	{
		stat_new = stat_old[0] | (1 << pin);

	}
	else if (value == 0)
	{
		stat_new = stat_old[0] & (~(1 << pin));
	}

	byte cfg[2] = { 0x01, stat_new };

	Wire.beginTransmission(0x20);
	Wire.write(cfg, 2);
	Wire.endTransmission();

}

图形化示例

版本历史记录

Version	Date	Note [+]新增[-]删除[^]修复
V2.0