Differences between the JackAl and Nextion displays

Most people don’t understand and won’t want to understand the differences between different types of display technologies.

Unfortunately,  the µBITx community has fractured its user base amongst competing screen technologies.   There are many different types of LCD display screens and they are not compatible at all.   

Differences between the Nextion and JackAl displays have been discussed on the BITX20 IO Group list following discussion about whether a Nextion screen used with the KD8CEC firmware could be ported across to the JackAl.  The simple answer is “No”!

Brian N8BDB notes that  it’s not going to be as simple as replacing a driver and rebuilding the application.  The Nextion display works in a very different way than the normal displays most people use for microprocessors like arduino and teensy.

Normally the display is a “dumb” device that just handles displaying the dots.  Software libraries are used to provide basic functionality like drawing lines, boxes, and text.  Touch events are handled completely separately by other libraries.

The Nextion display is the opposite.  The display has it’s own microcontroller, memory, etc. and the arduino communicates with it through a serial interface.  All of the buttons, text, gauges, etc. are prebuilt in the Nextion editor.  The application doesn’t know where they are on the screen.  It just has a name such as “button1” that is associated with a button on a particular screen for instance.  The application just sends a command to the display to change the text of “button1” to “abcd”.  It would require a significant rewrite of the JackAl UI code to make it work with a Nextion display.

The other thing as Jack pointed out is about resolution.  The Nextion displays most people have are much lower resolution than the display used by the JackAl board.  The 2.4″ and 2.8″ Nextion displays are 320×240.  The 5″ Nextion display ($60) is the closest one with similar resolution (800×480) and that is 33% more in price than the display ($40) that JackAl currently uses.  Even the 4.3″ Nextion display is only 480×272.

There are pros and cons of both screen types.  The Nextion costs a bit more per pixel because it has a processor on board, but the demand (in terms of memory and processing power) on the main µBITx is minimal.   The processor and screen communicate using a series of codes.   The Nextion (in theory) can be adapted to have quite different user interfaces for the same functions.  There are, in fact, at least two distinctly different versions of “look and feel” available already.   However, setting up these requires a fairly steep learning curve on the screen management environment.

On the other hand, the JackAl screen (along with all other types of LCD screens) is strongly tied into the firmware of the JackAl teensy processor and amending the “look and feel” of the display requires detailed knowledge of the processor, firmware and the screen programming environment on which the JackAl is built.  It is unlikely that the Nextion will be ported across to the JackAl environment any time soon.  Bite the bullet and buy a new screen!

Reference

KD8CEC releases CEC Beta firmware to support Nextion display

Ian Lee KD8CEC has released Beta firmware for the µBITx that supports Nextion colour touch screens .  He has also released matching files for installing firmware in the Nextion displays for 2.4″ and 2.8″ screen sizes.   No programming is required to use these displays.

The photo above shows the touch panel display.  Pressing on the screen will perform functions like changing band (up/down), changing frequency, adjusting the Attentuator (ATT), IF Shift and RIT, and going into Split mode.

See Ian’s webpage for details about downloading the various firmware options along with detailed instructions.

Buy your Nextion display now!

If this display looks like it is from a commercial rig, then you are wrong!  It is  the Nextion display mounted on a µBITx!

Ian KD8CEC will shortly release his newest enhancement to CEC firmware.  His latest modification to the CEC firmware supports Nextion screens. This was foreshadowed recently on the BITX20 list.


THIS WILL BE THE MOST AMAZING ENHANCEMENT YET FOR UBITX!

If you want further proof, check out Ian’s recently prepared youtube video of the Nextion screen in operation.  His release is imminent.

Get your order in for a Nextion display immediately, as they are likely to sell out when 6000 µBITx owners twig that they really do NEED a Nextion display.  [Note that ubitx.net has no relationship with ITEAD – who make the Nextion!]


Why Nextion?

There are some very good reasons why the Nextion display is the way to go:

  • Nextion screens make it quicker for developers to provide a user-friendly interface to their product:  a separate processor controls graphics on the screen, and a Windows WSYWIG emulator can be developed for free to whip up a User Interface for the Nextion display.   The processor in the Nextion has its own control language and coding that is similar to C++
  • Users can easily hack their own display’s look and feel, by plugging into a standardised protocol between the screen processor and main processor that are connected via a standard serial port.
  • Screens come in a variety of sizes from 2.4″ to 7″.  Resizing of images and buttons is all that is required to make firmware work on a different screen size. No coding is required.  Software required is simply the Nextion Windows software and a graphics programme (MS Paint is adequate).
  • The screens come in two varieties:  a BASIC model and an ENHANCED model.  The ENHANCED model has GPIO lines controlled by the display processor and a Real Time Clock (RTC).

Nextion display units cost more than other displays for a reason.  The independent processor removes most of the burden for screen manipulation from the main processor, and it is much quicker and easier to develop the user interface and to customise it for different sized screens and to add/subtract features.   Nextion displays also include a microSD card reader.  They run on +5v DC and include a serial port.   Note that the Enhanced Model contains a battery mount for the RTC, but does not include the battery (CR1220) itself.  This is not required until you want to use the RTC.

How easy will it be to use the Nextion Display?

It will be VERY EASY to add a Nextion display to your µBITx.  Watch the video!

No hardware modifications are required to your µBITx, but you will of course  need enough front panel space to install your colour touch display of choice.  You may even need a bigger case if you want to install the 7″ Nextion display!

You will also need to download two new files:

  1. an updated version of KD8CEC’s firmware, that incorporates the interfacing protocol to the Nextion for installation in your Raduino.
  2. an image file (firmware) for insertion in the Nextion display unit.

The downloaded firmware for the Nextion needs to match with your screen size.  There are two variants for each screen size:  a BASIC or ENHANCED version of the Nextion display unit (see the discussion on which version to buy below).

This firmware needs to be saved to a microSD card (a 2GB or larger card is required).  Insert the card in the Nextion display and in powering up the Nextion display will automatically load the firmware from the microSD card into the Nextion flash storage.   Remove the microSD card when the upload is complete.

Four wires connect the Nextion display to the Raduino.  Two lines are for power, and the other two are serial RX and TX that connect to standard IO ports on the µBITx that were used for the 16×2 standard display.

Reboot your µBITx and your Nextion display should be working!

What to look out for when buying a Nextion Display

There are two versions of the Nextion Display – one developed for the Chinese market and an English language version that supports the Nextion Windows development environment.  Make sure you don’t get the cheaper, but incompatible Chinese version.  Look out for “English Version” in the marketing blurb.  This won’t be an issue if you buy from the developer (ITEAD).

 I understand a downloadable hex file will be available that works the same as the English version, for those of us who purchased the wrong model in error!  Thanks to Ian, who did it blind (also not being able to read Chinese)!

Any size will work with the CEC firmware on the Raduino end.  However, Nextion firmware is specific to  either the BASIC or ENHANCED version of the screen and to the resolution of the screen.   That said, any version can be modified to work with any other screen size with just a little bit of work on the part of the user.   You can also fully customise your screen to meet your own requirements.  Change the colours, or change the entire look and feel.  No coding is required to do this, just cut and paste the code from the supplied CEC version for each tool.

Purchase the ENHANCED model of the Nextion (for a few more dollars) if you think you will use the GPIO or RTC features in future.  The RTC could be useful for digital modes that require precise timing, or for satellite work, etc.  Additional GPIO lines could solve one of the problems with the Raduino:  a lack of spare digital ports to support customised add-ons.  For example, if you want to add 160m and switch in an additional LPF, or  if you are worried about potential spurs, you will be able to pull in bandpass filters for the high bands. In these instances you may want to spend a little more to get the ENHANCED version.

If you don’t want to wait until firmware is available for your screen size, then purchase a 2.4″ or 2.8″ BASIC or ENHANCED Nextion Display now.   These two screens have the exact same resolution, and the default version of the Nextion Firmware from Ian KD8CEC will work on both screen sizes without modification.

If you already have a different sized screen, or want to buy a bigger screen, right from the outset, don’t panic.  You may need to make some adjustments to the firmware yourself.  This is not difficult – but involves resizing graphics and moving around objects to suit the larger screen area/resolution.  Some of us are working on modifications to the Nextion firmware to accommodate 3.2″ and 3.5″ screens. Firmware for these screens is likely to be available quickly.

Screen sizes and resolutions for the BASIC models available on ITEAD’s website are as follows:

The ENHANCED versions available from ITEAD are as follows:

Most of us will choose to buy our Nextion displays from Aliexpress or eBay.

They are available in all sizes and in either BASIC or ENHANCED versions.  It is unclear which are OEM versions and which are clones.  It probably doesn’t matter.

Look for highly rated suppliers and those with higher shipping volumes.  The biggest risks are that your screen arrives cracked, or simply never arrives.  You will need some form of redress when goods arrive in a damaged state or simply never arrive, and this is where the intermediaries in eBAY, Aliexpress or Paypal can assist.

 

Nextion Display and KD8CEC firmware

Ian KD8CEC is working on a protocol to allow Nextion LCD touch displays to communicate with the µBITx.

He is implementing this a little differently to most support for Nextion LCDs.

The firmware will handle communication between the uBITX arduino and Nextion LCD using template files.

There are quite a few variables in the Nextion LCD. If the status of any parameters in the uBITX changes, the variables sent to the Nextion LCD will also be changed at the same time (and vice-versa).  This should allow any Nextion display and any configuration of the display’s User Interface to interact with the µBITx.  This means constructors can customise their µBITx display using the Windows GUI used with the Nextion to configure the “look and feel”.

For example, when uBITX’s frequency changes, it is transferred to a specific variable on Nextion LCD.

Example code

 

Below is an example of simple frequency and mode display changes

 

//Frequency

if(vc.val!=-1)

{

nFreq.val=vc.val

vc.val=-1

}

//Mode

if(cc.val!=-1)

{

if(cc.val==2)

{

tMainMode.txt=”LSB”

}

else

{

    tMainMode.txt=”USB”

}

cc.val=-1

}

Reference

Nextion Display

Fred W4JLE writes that he has just discovered the NEXTION display and he has begun using it on his BitX.

He says “what makes it really neat is the software that can be downloaded from the manufacturer’s site. It takes all the pain out of graphics programming. I have replaced the UNO with an STM32 as in addition to the normal stuff I have added a GPS module.”

The display shows time/location/grid square data as well as using the 1PPS in the GPS module to do a continuous correction to the SI5351a oscillator. The higher resolution allows calculating the SWR etc. with much finer gradations.

Fred says he will be adding a filter board from a CODAN that will allow all band operation which he purchased for $12.00 on eBay.

Fred’s concluding comment is that it is “Amazing what is available to the homebrewer today!”.

We are eagerly awaiting a link to his sketch and to see photos of his uBITx!

Reference