Custom Screen Firmware

Last Update: Nov 17, 2020 @ 11:54 Preliminary information, subject to change.

All apps controlling a Decaf LCD require a set of user interface screens that are created with the PiXCL 20 USBLCD* command set. This might be as simple as a few graphics regions and some text. A more complex screen or a screen set can require a lengthy set of USBLCD* commands, which takes a finite interval to send to the board. Rendering time to the LCD is a small fraction of this interval.

In most cases, the set of commands can be turned into a firmware update that renders the screen directly. The app simply has to specify the required page number via the USBLCDUserScreen command, which is noticeably faster. Examples are the firmware PowerOnScreen and PiXCL promotional screen. Here’s some examples with the firmware version followed by the slower app code version. Try starting and re-starting the video at relevent points to see how much faster the firmware versions render, compared to the app code.

We offer an affordable development service for custom screens.

How does this paid service work?

You send us the working PiXCL app code that generates the screen or screens, and we review it. We may offer suggestions for code improvements. On mutual agreement for the screen content and acceptance of the development contract price (see details below), we update the firmware build for your device, which you download and install using DFU.

What are the payment terms?

You will be engaging PiXCL Automation Technologies Inc. to do code development work for you under a legally binding written contract. Custom development requires an up-front payment of CAD$100 which covers your project setup and the first review of the app code. Development of custom screen firmware updates from app code is usually not difficult, but thorough testing is always required, and this takes time. On completion of in-house testing, we provide you with a video of the working screen, at which point the final payment is required to release the new firmware for download.

Firmware development of each custom screen is $50, quantity 1-5. To be clear, if your project requires multiple screens, it’s most cost effective to have them created in a single contract.

For larger projects that require more than 5 custom screens, or development support for several different Decaf models (e.g. an IOC-440 and IOC-370) contact us with your requirements.

All development project payments are currently handled via PayPal.

Supported Hardware and Software

Decaf IOC-280 / 235 / 350 / 440 / 370 are the supported boards. The new firmware upgrades the boards to v20.1 or later. PiXCL 20.1 is supplied with the new firmware.

How many Use Screens can be stored?

There is an upper storage limit which is the available Decaf mcu Flash memory. The binary size of a User Screen varies, so a realistic upper limit is around 32.

Who owns the User Screen content?

Assuming the screen set is application specific to your project, you do. If you have a suggestion for a generic screen that would be useful to other users, let us know. We may add it to the standard user screen set.

How long does this custom development take?

Typically 2-3 days from receipt of the initial contract payment.


Minor cosmetic changes will be done at no charge for 30 days from the date of final payment. After that time, any changes or additions is considered a new development contract.