TFT LCD Direct Drive Demo Kit - H8S/2456

Editor Review

Ease of Set-Up:

Documentation Completeness and Clarity:

Hardware Completeness and Quality:

Meets Expectations:

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Overall rating:

Time to Complete

Prerequisite Skills

Solid experience programming with C.  Experience with a real-time operating system helpful. This kit uses the FreeRTOS.  Experience with graphic displays also helpful.
 

What We Liked

Good hardware, easy to set up, demo software ran immediately. Good documentation comes with the kit on CD-ROMs.  Good software development tools from Renesas.
 

What we Didn't Like

The example in the getting-started booklet only reloads the original example back into the host microcontroller. No documentation explains what to do with the kit next, so you're on your own.
 

Full Review

The Renesas YLCDRSK2456S kit comes with a baseboard that holds a color thin-film-transistor (TFT) LCD that measures 480 by 272 pixels. A separate development board for a Renesas H8S2456 MCU attaches to the the LCD and drives it directly.  The LCD comes with a touch-panel interface.  The package includes a power supply, an  E10A JTAG debugger/programmer pod, cables, and two CD-ROMs.  The CDs contain software specific to the LCD as well as the Renesas High-performance Embedded Workshop (HEW).  I have used the HEW tools to program and debug code and like them.

Before you install any software, you can connect the two boards and apply power. The pre-loaded software will run through a Renesas splash display followed by a colored display that offers six demonstrations. The demo programs worked well and shows developers the types of displays they can create and the types of touch-screen controls they can implement.  The getting-started information is clear and developers will have no difficulty understanding it and getting off to a good start.

Developers should understand, though, that this type of direct-drive LCD arrangement is aimed at applications that require only limited animation. Thus, you should not expect it to provide real-time response such as you would find on an oscilloscope display or in an electrocardiogram recorder.  The LCD operates on sets of preloaded images that the MCU delivers through direct-memory-access (DMA) operations under control of the FreeRTOS operating system.  But you can still create on-screen controls such as buttons and sliders controlled by touch. Unfortunately, the documentation doesn't explain how to do so.

Installation of LCD and HEW software, as well as documentation and code examples, took about half an hour.  I spent another half hour going through the example and reviewing documentation.  I also spent time looking for more tutorials on the Renesas Web site.  The kit's documents included:

1.  H8S/H8SX Families: Direct Drive LCD Demo Application Note that explains the structure of the example program, configuration of the project, calculation of touch-screen position, and other aspects of the pre-loaded software.

2.  H8S/H8SX: Direct Drive LCD Design Guide, Version 2.6 User's Manual.  This information explains how code configures the LCD Direct Driver via macros. Developers have a list of macros, a description of each one, the units they use--Hertz, percent, lines, dots, and so on, and the location of the macros in the demonstration (or example) code.  Each macro has its own page that shows its format, parameters, return value (if any) and a description of the macro and a snippet of code that shows how to use the macro.  Bravo, Renesas.  I wish more MCU companies included this type of information with their eval kits.

3.  H8S/H8SX Series: GAPI Graphics API Version 1.21 User's Manual.  In this document, developers get an introduction to the API Renesas has fashioned to help them create applications at a level that moves them away from the low-level LCD control operations.

The only documents I didn't like?  The schematics, as usual.  Lines are thin and difficult to read, although legends stand out nicely. You can read the schematic diagram on a monitor screen, though.

Instructions in the getting-started booklet explain how to open an existing project, build it, download it to the MCU, and run it.  But it's the same example Renesas ships ready-to-run on the MCU, so the example appears more like a cook-book walk-through than anything creative.

I had hoped for some examples or tutorials that would include basic code that would illustrate how to take a bit-map image file (.BMP)--the only type the display's control code works with--and get it to appear on the LCD.  Unfortunately, you're pretty much on your own after you run the canned example Renesas provides.  I thought this example looked overwhelming for a newcomer to the H8S architecture, LCDs, and the FreeRTOS software.  Developers would benefit greatly from several basic tutorial projects that do simple things with the LCD and the touch screen.  Some developers might just give up and look for another approach to deliver an easier-to-understand eval kit.  I know I would.

As noted above, the kit's software works with BMP images, but developers must run them through a conversion process that creates a Motorola S-record file.  I won't go into the details here.  Renesas supplies a command-line program, bin_to_Mot.exe, that combines many image or sound files, for example, into one file that the HEW tools will load into serial flash memory on the MCU eval board.  Unfortunately, the information does not explain how to use the bin_to_Mot.exe program and even the instructions on how to start this software seem too brief.  Hint: Open an MS-DOS window in Windows, locate the bin_to_Mot.exe file and run it.  It will produce some information in the DOS window that can help you.  But you'll have to determine the proper addresses to use when you assign images to memory.  That's the sort of information Renesas should add to help developers.

So, you don't just load BMP images into the serial flash memory and have the FreeRTOS scroll through them.  The process requires some hand holding, which the kit doesn't provide.

As noted above, Renesas did send me several files of "...plug-ins that can be used with the LCD program for additional functionality."  But I had to submit a tech-support query to obtain them. When I tried to search the Renesas Web site for "LCD_Plugins" or "LCD Plugins," the site stalled out and the search engine proved unresponsive to all my search requests.  A Google search for the same terms did not uncover any code. I didn't want to add "functionality" to the kit, I wanted to understand how I could use it.

If you have time to wade through a lot of C code to discover how to control the LCD, this kit might be for you.  I cannot recommend it, though, until Renesas provides several tutorials for the rest of us who must spend time solving our own problems.  --Jon Titus
 

Samples & Tutorials

Renesas has add-in code that will developers can use, but no link to them exists (as of 1 March 2010) on the Renesas Web site.  Submit a Technical Support request and ask for the LCD_Addins.ZIP file.  Renesas might have other application code and tutorial information available later, so check the Renesas Web site for current information and feel free to leave a comment and a link here to help your colleagues.

TFT LCD Direct Drive Demo Kit - H8S/2456 Review

About the Editor

Jon Titus

Sr. Technical Editor

Evalkits.com

jon.titus@evalkits.com

Jon Titus regularly contributes articles on electronics and measurement. He has extensive experience designing with microprocessors and microcontrollers, and developed data-acquisition and instrument-control systems and taught many courses on software and hardware design. A recipient of the George R. Stibitz Computer & Communications Pioneer Award, he holds a BS from Worcester Polytechnic Institute, an MS from Rensselaer Polytechnic Institute, and a PhD from Virginia Polytechnic Institute.

Comments

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#1

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Posted By:

#2

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Where to Buy TFT LCD Direct Drive Demo Kit - H8S/2456