Tag Archives: LEDE

Configuration, Software

LEDE on Linkit 7688 Duo – Timecheck example

2017-08-13 admin

After the Python ad Firmata example

Firmata and Python

in this example we use the following programming model

We enable the board to work like Arduino Yun

Linkit 7688 Duo Arduino Yun

As specified in the Mediatek link, you must enable the bridge on the board; from a terminal in Lede run

uci set yunbridge.config.disabled='0'  
uci commit  
reboot

uci set yunbridge.config.disabled='0'

uci commit

reboot

At the reboot go to the Arduino Ide and choose File->Examples->Bridge->TimeCheck

We used the 1.6.5 Arduino Ide; we had issues whith the 1.8 version to build the sketch.

From the Arduino Ide, after the code upload, go to Tool->Serial Monitor to open the serial monitor

The serial monitor window shows the current time.

After that, to run the other examples , disable the bridge setting with the commands

uci set yunbridge.config.disabled='1'  
uci commit  
reboot

uci set yunbridge.config.disabled='1'

uci commit

reboot

Configuration, Software

LEDE on Linkit 7688 Duo – Firmata and Python

2017-08-05 admin

After the python test in the previous article

LEDE on Linkit 7688 Duo – MPU-MCU Uart communication

here we describe how to do the same operation using the Firmata python library

Firmata Protocol

In this case, the programming model is the following

As first step, described in the Mediatek article

Using Firmata with Python

we install the Firmata python library; in a linux terminal on LEDE run

pip install pyfirmata

1	pip install pyfirmata

In the Arduino IDE choose File->Examples->Firmata->StandardFirmata

Make the following change in sketch code:

Look for the code

Firmata.begin(57600);
while (!Serial) {

and replace it with

Serial1.begin(57600);
Firmata.begin(Serial1);

while (!Serial1) {

Save the file and perform the compilation and upload on the Linkit 7688 Duo.

In a linux terminal in Lede create the blink_with_firmata.py file and copy the following code inside

from pyfirmata import Arduino, util
from time import sleep
 
board = Arduino('/dev/ttyS0')
print "Start blinking D13"
while True:
    board.digital[13].write(1)
    sleep(0.5)
    board.digital[13].write(0)
    sleep(0.5)<span class="kwd">  </span>

from pyfirmata import Arduino, util

from time import sleep

board = Arduino('/dev/ttyS0')

print "Start blinking D13"

while True:

board.digital[13].write(1)

sleep(0.5)

board.digital[13].write(0)

sleep(0.5)<span class="kwd"> </span>

Save and quit.

Always in a linux terminal run now

python ./blink_with_firmata.py

1	python ./blink_with_firmata.py

The LED on the card should turn on and off.

Below is the link to download the two files ready for the Link 7688 Duo

Lede Python Firmata files

In the next article we’ll enable the board to work like Arduino Yun

LEDE on Linkit 7688 Duo – Timecheck example

Development, Software

LEDE on Linkit 7688 Duo – MPU-MCU Uart communication

2017-07-29 admin

After the building and installion of the LEDE firmware on the Linkit 7688 Duo card

Installation and configuration of Lede image on Linkit 7688 Duo

let’s test the functionality of some features on the card.

You can find the Mediatek article with the programming model

Programming model

As a first example we treat the one on the Mediatek site as described in the title of the article

Linkit 7688 DUo MPU-MCU Uart Connection

which corresponds to the following programming model

As first step, Arduino IDE is configured as described in the link

Arduino IDE for Linkit 7688 Duo

the following code is uploaded on the Linkit 7688 Duo

void setup() {
    Serial.begin(115200);  // open serial connection to USB Serial port (connected to your computer)
    Serial1.begin(57600);  // open internal serial connection to MT7688AN
                           // in MT7688AN, this maps to device
    pinMode(13, OUTPUT);
    }
 
void loop() {
    int c = Serial1.read();      // read from MT7688AN
    if (c != -1) {
        switch(c) {
          case '0':                // turn off D13 when receiving "0"
             digitalWrite(13, 0);
            break;
          case '1':                // turn off D13 when receiving "1"
             digitalWrite(13, 1);
            break;
        }
    }
}

void setup() {

Serial.begin(115200); // open serial connection to USB Serial port (connected to your computer)

Serial1.begin(57600); // open internal serial connection to MT7688AN

// in MT7688AN, this maps to device

pinMode(13, OUTPUT);

}

void loop() {

int c = Serial1.read(); // read from MT7688AN

if (c != -1) {

switch(c) {

case '0': // turn off D13 when receiving "0"

digitalWrite(13, 0);

break;

case '1': // turn off D13 when receiving "1"

digitalWrite(13, 1);

break;

}

This code manages the LED by the MCU according to the commands that the MCU receives at the Serial1 port.

Logic is handled instedad by python code that runs on Linux; create a file for this purpose, such as blink.py in a linux command shell on the board, with the following code

import serial
import time
 
s = None
 
def setup():
    global s
    # open serial COM port to /dev/ttyS0, which maps to UART0(D0/D1)
    # the baudrate is set to 57600 and should be the same as the one
    # specified in the Arduino sketch uploaded to ATmega32U4.
    s = serial.Serial("/dev/ttyS0", 57600)
 
def loop():
    # send "1" to the Arduino sketch on ATmega32U4.
    # the sketch will turn on the LED attached to D13 on the board
    s.write("1")
    time.sleep(1)
    # send "0" to the sketch to turn off the LED
    s.write("0")
    time.sleep(1)
 
if __name__ == '__main__':
    setup()
    while True:
        loop()

import serial

import time

s = None

def setup():

global s

# open serial COM port to /dev/ttyS0, which maps to UART0(D0/D1)

# the baudrate is set to 57600 and should be the same as the one

# specified in the Arduino sketch uploaded to ATmega32U4.

s = serial.Serial("/dev/ttyS0", 57600)

def loop():

# send "1" to the Arduino sketch on ATmega32U4.

# the sketch will turn on the LED attached to D13 on the board

s.write("1")

time.sleep(1)

# send "0" to the sketch to turn off the LED

s.write("0")

time.sleep(1)

if __name__ == '__main__':

setup()

while True:

loop()

Running the code

python ./blink.py

1	python ./blink.py

the LED on the card should turn on and off continuously.

In the next example we’ll use the Firmata python library to perform the same operation

LEDE on Linkit 7688 Duo – Firmata and Python

Installation, Software

Installation and configuration of Lede image on Linkit 7688 Duo

2017-07-19 admin

After you have attached to the board the support devices, as specified in the previous article

Linkit 7688 Duo Connections

and built the image

Lede Image for Linkit 7688 Duo

we upload the image to the device.

Following the documentation availble at the link

Update the firmware with a USB drive

to update the firmware copy the lede-ramips-mt7688-LinkIt7688-squashfs-sysupgrade.bin file to the root directory of a FAT32 USB drive and rename it as lks7688.img.

Attach, now, the USB drive to the HOST port of the board with an OTG cable and follow the steps

Press and hold the on-board WiFi button.
Press the MPU reset button once, while holding the WiFi button.
Keep holding the WiFi button for about 5 seconds. Do not release until the orange LED for WiFi is off. DO NOT press the WiFi button longer than 20s or it will upgrade the bootloader.
The device will automatically reboot after firmware update is complete.

You can control the operation via the USB TTL serial connected to the PC and activated on the enabled Com port with the following settings

Port: Enabled COM
Speed: 57600
Data Bits: 8
Stop Bits: 1
Parity: None
Flow Control: XON/XOFF

Use, for example, putty to connect, press Enter if the screen is not active, and to check the steps the system is runnig when upgrading

When the orange LED starts blinking at a lower frequency the card is ready to be used

On the Lede system, the wireless card is disabled by default, while Lan is operational, but only accessible via a Breakout board

Linkit Breakout

To enable the wireless card connect with putty (screen on Linux) to the previously connected USB TTL serial and go to the /etc/config folder; edit the network file and add at the end the following section

config interface 'wlan'
        option proto 'dhcp'

1 2	config interface 'wlan' option proto 'dhcp'

Save and run

uci commit network

1	uci commit network

Edit the wireless file and add at the end the section

config wifi-iface 'sta_radio0'
        option device 'radio0'
        option mode 'sta'
        option ssid 'Access Point'
        option key 'password'
        option encryption 'psk2'
        option network 'wlan'

config wifi-iface 'sta_radio0'

option device 'radio0'

option mode 'sta'

option ssid 'Access Point'

option key 'password'

option encryption 'psk2'

option network 'wlan'

where Access Point and password indicate the Access Point name and password; the wireless security setting is wpa2.

Save and run

uci set wireless.radio0.disabled=0; uci commit wireless;

1	uci set wireless.radio0.disabled=0; uci commit wireless;

Enable the wireless, running

wifi

wifi

Access the Lede interface with the address assigned by the Access Point

Set the password and access to the Lede management.

In this firmware, the leds on the board are not synchronized with wireless operations, unlike from OpenWrt firmware with the Mediatek proprietary interface and drivers.

In the next article, we will give some examples of interfacing with the arduino IDE, based on the tutorial on the Mediatek site using this custom Lede image

LEDE on Linkit 7688 Duo – MPU-MCU Uart communication

Compilation, Software

LEDE building for Linkit 7688 Duo

2017-07-09 admin

After OpenWrt image building using the Mediatek SDK

OpenWrt building for Linkit 7688 and 7688 Duo

this article describes how to generate a LEDE image for the Linkit 7688 Duo.

The steps on how to compile LEDE are available at the link

LEDE Building

Clone the code from the github in a shell command window, always from the Linkit folder

cd
cd Linkit

1 2	cd cd Linkit

run

git clone https://git.lede-project.org/source.git Lede

1	git clone https://git.lede-project.org/source.git Lede

Create the src folder under Linkit and extract the compressed file

Feed for Linkit

This feed was created from Mediatek one, eliminating the binary drivers dependency.

Copy the file to the src folder and uncompress it

sviluppo@debian:~/Linkit/src$ ls
linkit.tar.gz
sviluppo@debian:~/Linkit/src$ tar -zxvf linkit.tar.gz

sviluppo@debian:~/Linkit/src$ ls

linkit.tar.gz

sviluppo@debian:~/Linkit/src$ tar -zxvf linkit.tar.gz

sviluppo@debian:~/Linkit/src$ ls
linkit  linkit.tar.gz
sviluppo@debian:~/Linkit/src$

sviluppo@debian:~/Linkit/src$ ls

linkit linkit.tar.gz

sviluppo@debian:~/Linkit/src$

Go to the Lede folder and copy the feeds.conf.default file as feeds.conf

cd 
cd Linkit/Lede
cp feeds.conf.default feeds.conf

cd Linkit/Lede

cp feeds.conf.default feeds.conf

Run

echo src-cpy  linkit ~/Linkit/src/linkit >> feeds.conf

1	echo src-cpy linkit ~/Linkit/src/linkit >> feeds.conf

Update the feeds for the packages

./scripts/feeds update

1	./scripts/feeds update

Install the packages

./scripts/feeds install -a

1	./scripts/feeds install -a

Configure the kernel executing

make menuconfig

1	make menuconfig

Use the following settings

Target System: Mediatek Ralink MIPS
Subtarget: MT7688 based boards
Target Profile: Mediatek LinkIt Smart 7688

In the Base system section enable mtk-linkit

Save and exit.

Run the building

make V=s -j x

1	make V=s -j x

where x is the number of cores to use in the building.

At the end of the process the generated image is available in the bin/targets/ramips/mt7688/ folder as lede-ramips-mt7688-LinkIt7688-squashfs-sysupgrade.bin.

The built firmware is available here

Lede Image for Linkit 7688 Duo

WARNING: The image installation on the device is at your own risk. We accept no responsibility if the installation leads to malfunction or block of the device.

If you upgrade the board using an usb key, you need to rename the lede-ramips-mt7688-LinkIt7688-squashfs-sysupgrade.bin file in lks7688.img.

This firmware may have malfunctions as it is not thoroughly tested and based on drivers under development.

In the next articles we’ll upload the images to the board and configure them

Installation and configuration of the Openwrt Image on Linkit 7688 and 7688 Duo

Hardware

Linkit 7688 Duo Connections

2017-07-09 admin

After the board specifications summary

Linkit 7688 and 7688 Duo Development Boards

this article describes how to connect to the board the following components that will be used later:

Micro USB OTG to the Host port
USB TTL Serial Device
5 V power supply to the port USB Power

The following diagram shows the connections to the board

The table below shows the connections between the USB TTL Serial device and the board

USB TTL Pin	Linkit Pin
RX	UART_TXD2
TX	UART_RXD2
GND	GND

In the netxt article we will show how to build the firmware for the Linkit 7688 and Linkit 7688 Duo

OpenWrt building for Linkit 7688 and 7688 Duo

Micro Devices

Tag Archives: LEDE

LEDE on Linkit 7688 Duo – Timecheck example

LEDE on Linkit 7688 Duo – Firmata and Python

LEDE on Linkit 7688 Duo – MPU-MCU Uart communication

Installation and configuration of Lede image on Linkit 7688 Duo

LEDE building for Linkit 7688 Duo

Linkit 7688 Duo Connections

Blog about embedded devices