OpenWRT Smart 7688 IoT board

• USB 2.0 Mirco Type B Plug.
• 580 MHz MIPS CPU.
• Single input single output(1T1R) Wi-Fi 802.11 b/g/n (2.4G).
• Pin-out for GPIO, UART and Ethernet Port
• 32MB Flash and 128MB DDR2 RAM
• USB host & USB device
• Micro SD slot
• Provide optional connection golden finger for connect other device without soldering.
• Provide extra 3V USB power source for other device, Do not worry to find extra power source.
• build-in reset button and Wifi button.
• OpenWRT compatible.
• Python, Node.js and C programming languages
• Support file share(samba), putty and Termite tools.
• Using Silicon Lib as Virtual COM port Device dirver.

• IoT/Gateway Device.
• Robotics.
• Teaching and learning.

• OpenWRT Smart7688 IoT
• Silicon labs CP2102 usb to uart bridge (built-in 5V to 3.3V Low dropout power regulator.)
• MT7688 broad
• Master broad with golden finger

External Antenna package set

• Antenna socket holder
• Antenna cable
• External Antenna

Internal Antenna package set

• PCB Antenna with cable

Without Antenna package set

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• USB Host connect to device units
• USB Power connect to PC for UARTs



 

• USB Host connect to mass storage
• USB Power connect to PC for UARTs



 

After connect to PC, you may run UART communication tools eg: termite.
Serial port setting:
Baud rate 57600
Data bit 8 , Stop bits 1 , parity none

LinkIt Smart 7688 Web UI allows you to configure system information, upgrade firmware, perform device reset and change between Wi-Fi AP and Station mode and more. The following steps apply to Windows, Mac OS X and Linux.

• 1) Power on Module development board by using any USB power source, for example your computer and a micro USB cable.

  Make sure you connect the cable to the Power (PWR) connector, not the USB host (HOST) connector near the MPU reset button. The green ON LED (Power on) will light up solid first, followed by a blink from the orange Wi-Fi LED (bootloader initialization). Then, after about 5 seconds, the device boot up starts.

  After boot up, the Wi-Fi LED turns off. This means the system is ready to accept Wi-Fi connection and the steps are described next.

• 2) Open the Wi-Fi connection utility on your computer and connect to the access point named LinkIt_Smart_7688_1B09F3 (1B09F3is the MAC address and yours could be different).

  After you have connected to LinkIt_Smart_7688_XXXXXX AP, the Wi-Fi LED will blink three times per second.

  Keep in mind that once you have connected to Smart7688IoT, your computer may no longer have access to the internet - it is now joined the Local Area Network formed by Smart7688IoT.

  Default SSID: LinkIt_Smart_7688_XXXXXX
  mDNS Hostname: mylinkit.local
  IP: 192.168.100.1
  

• 3) In your web browser open http://mylinkit.local

  

• 4) Click on the Password field and set a password using at least 6 alphanumeric characters. Click Submit and enter the password again to Sign In.

Reset or network Re-configuration.

Config to Access Point Mode (AP mode)

In AP mode a Smart7688 IoT development board forms a LAN and acts as an access point. AP mode is used mainly to configure the board settings.

Default SSID: LinkIt_Smart_7688_XXXXXX
mDNS Hostname: mylinkit.local
IP: 192.168.100.1

Config to Station Mode in Network setting.

In Station mode a LinkIt Smart 7688 development board is able to access the Internet by joining a Wi-Fi network.

mDNS Hostname: mylinkit.local
IP: Assigned by Wi-Fi AP

• 1) Install PuTTY from here.
• 2) Type mylinkit.local in the Host Name box, check the SSH radio button and click Open as shown

  

• 3) A Security Alert window will pop up as shown in Figure 20 below, this happens when you use PuTTY for the first time, or after upgrading firmware, or use a different board. Click Yes.

  

• 4) In the PuTTY terminal window that opens, log in with username root and enter the password you set previously in the Web UI, after log in you should see a screen similar to

  

  

   

• For Mac:

  Open Terminal. In the Terminal, type ssh root@mylinkit.local at the command line, hit return and you'll be prompted to enter the root password. Enter the password you set previously in the Web UI.

   

• For Linux:

  Open Terminal. In the Terminal, type ssh root@mylinkit.local at the command line, hit return and log in using the password you set previously

   

• Connection information

  Host name: mylinkit.local
  Port: 22
  Connection type: SSH
  Login User name root
  

   

Enable samba for (Read / Write)

Open Termite and type chmod 777 /Media

Open file explorer and type \\mylinkit.local, you should see the Media folder. Open another file explorer, drag and drop your file to Media folder, show below.

Use Python and mraa control GPIO interface

Create new Python code

(example code is flash LED)

1. Use vim editor

vim blink.py
  

 

2. write python code and save.

import mraa  
import time  
# Refer to the pinout digram for the GPIO number to silk print mapping # in this example the number 44 maps to Wi-Fi LED.
pin = mraa.Gpio(44)  
pin.dir(mraa.DIR_OUT)  
while True:  
   pin.write(1)
   time.sleep(1)  
   pin.write(0)
   time.sleep(1)
  

 

3. Run python code.

python ./blink.py  
  

Use Node.js and mraa control GPIO interface

Create new javaScript code

This example code is through Web Server control GPIO to flash LED

Type http://mylinkit.local:8080/?value=high in Web browser to ture off LED

Type http://mylinkit.local:8080/?value=low in Web browser to ture on LED

1. Use vim editor

vim Jsserver.js
   

 

2. write javascript code and save.

var m = require('mraa');
var ledPin = 44
var myLed = new m.Gpio(ledPin);
myLed.dir(m.DIR_OUT); 
var url = require('url');
var http = require('http');
var onoff = "led off";
http.createServer(function(request, response) {
    var params = url.parse(request.url, true).query;
    try {
        if (params.value.toLowerCase() == 'high') {
            myLed.write(1);
            onoff = "led off";
        } else if (params.value.toLowerCase() == 'low'){
            myLed.write(0);
            onoff = "led on";
        }
    } catch(e) {
    }
    response.writeHead(200);
    response.write("The value written was: " + params.value + "(" + onoff +")");
    response.end();
}).listen(8080);
console.log('Listening on port 8080 ...');
   

 

3. Run javascript code , (Ctl-C)exit.

node Jsserver.js
   

 

Test 1 , Use Web browser to ture off LED



Test 2 , Use Web browser to ture on LED

Example use comand to control GPIOs

Create Output GPIO2

GPIO entry point at /sys/class/gpio folder. You type follow script to access port 2 for output.

Output '1' to GPIO2

echo 2 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio2/direction
echo 1 > /sys/class/gpio/gpio2/value
echo 2 > /sys/class/gpio/unexport
   

Output '0' to GPIO2

echo 2 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio2/direction
echo 0 > /sys/class/gpio/gpio2/value
echo 2 > /sys/class/gpio/unexport
   

Create Input GPIO2

GPIO entry point at /sys/class/gpio folder. You type follow script to access port 2 for input.

input value form GPIO2

echo 2 > /sys/class/gpio/export
echo in > /sys/class/gpio/gpio2/direction
cat /sys/class/gpio2
echo 2 > /sys/class/gpio/unexport
   

Build Firmware and bootloader

• Build the firmware from source codes

• Build the bootloader

Note:

Power Up reset lock

Once Linux system boot up than the system is locked until power off.

Resources