4D SGC TFT Screen

Table of Contents

  1. Presentation
  2. Connecting the screen
  3. 4D SGC Library
  4. Demo
  5. Work in progress
  6. Notes

Presentation

This page presents a library to use a 3,2" touch screen from 4D Systems (http://www.4dsystems.com.au/) in Australia. The screen details are :

  • Low-cost LCD display graphics user interface solution.
  • 240 x 320 QVGA resolution, 65K true to life colours, TFT screen.
  • Display Viewing Area: 48.6 x 64.8mm
  • Integrated 4-Wire resistive Touch Panel.
  • Easy 5 pin interface to any host device: VCC, TX, RX, GND, RESET.
  • Asynchronous hardware serial port, TTL interface, with 300 baud to 256K baud.
  • Powered by the 4D-Labs PICASO-SGC processor (also available as separate OEM IC for volume users).
  • On-board micro-SD memory card adaptor for multimedia storage and data logging purposes. HC card support is also available for cards 4Gb and larger.
  • DOS compatible file access (FAT16 format) as well as low level access to card memory.
  • Dedicated PWM Audio pin supports FAT16 audio WAV files and complex sound generation.
  • On-board audio amplifier with a tiny 8 Ohms speaker for sound generation and WAV file playback.
  • Comprehensive set of built in high level graphics functions and algorithms that can draw lines, circles, text, and much more.
  • Display full colour images, animations, icons and video clips.
  • Supports all available Windows fonts and characters (imported as external fonts).
  • 16 x General Purpose I/O pins. Upper 8 bits can be used as an I/O Bus for fast 8-bit parallel data transfers.
  • 2 x 30 pin headers for I/O expansion and future plug-in daughter boards.
  • 4.0V to 5.5V range operation (single supply).
  • Module dimensions: 55.1 x 77.0 x 13.8mm (not including mounting tabs).
  • 4 x snap-off mounting tabs with 3mm holes for mechanical support.
  • RoHS Compliant.

/media/uploads/Kerpower/p1254239816.jpg /media/uploads/Kerpower/p1254239844.jpg

Connecting the screen

  • You will need to power the screen with 5V. Beware! Some screens need more power than the computer USB link can provide. For my screen, I had to use an external 5V source.
  • If you use an external power source, make sure the mbed ground and external power ground are linked otherwise the serial commands will not be received correctly by the screen.
  • Use one of the three Serial pairs of pins (p9, p 10) (p13, p14) or (p27, p28) from the mbed to connect them with the screen.
  • Use one pin for reseting the screen.

4D SGC Library

You can import the 4D SGC library from here :

» Import this library into a program4DGL

This is a library for 4DGL screens from 4D Systems in Autralia (http://www.4dsystems.com.au). Most graphic, touch and text functions are supported

Last commit 17 Oct 2010 by user Stephane ROCHON

To use it, you just have to insert the header file TFT_4DGL.h in your main.cpp and create an object using the TFT_4DGL class.

#include "mbed.h"
#include "TFT_4DGL.h"

TFT_4DGL my_screen (p9, p10, p11); // serial tx, serial rx, reset pin;

Demo

Even simpler, you can import this demo :

» Import this program4DGLtest

Last commit 17 Oct 2010 by user Stephane ROCHON

Work in progress

  • The library has to be documented for clarity
  • About 60% of the screen functions are supported, there are still some developpement work

Notes

There is a modified version of this library available which corrects the following assert "*** assertion failed: 0, file serial_api.c, line 115". It can be found here:

» Import this library into a program4DGL

Fixed a few minor issues in 4DGL library Moved pc serial port object used for debug output into 4DGL object itself. Previously it was a global object but its constructor wasn't getting run before the global constructor for the 4DGL object itself which led to an assert in the serial code. I also fixed a few potential buffer overruns that I saw in the code as well.

Last commit 05 Jul 2011 by user Adam Green

Forum thread discussing issue can be found here



Post a comment Ask a question
Last modified 08 Jul 2011, by user Adam Green. 15 comments tag 4D SGC, color, screen, touch

15 comments:

user Anna C
11 Nov 2010

Dear Stephane,

Thank you for your program and library, it allowed me to evaluate the effectiveness of mbed with a 4D TFT touch display. There are however a couple of minor points about the documentation.

It seems that you have written a wrapper around the SGC commands, where the mbed is the host microcontroller. This is in contrast to GFX, which creates a standalone module out of the display, and 4DGL is a programming language for GFX-based displays. Please find the definitions of SGC (Serial) and GFX (4DGL) platforms below, which has come from 4D Systems:

"(SGC) Serial Platform: The (SGC) Serial-Platform modules are based on the PICASO-SGC Serial Graphics Controller chip. In this mode, the PICASO-SGC becomes the slave device controlled by an external host controller. This allows you to develop your graphics applications using the host controller’s development platform and software tools. The PICASO-SGC chip has a rich set of serial commands built inside the chip and the commands are sent from the host controller via the serial (UART) interface. All it takes is a few bytes of serial data from the host controller and you can quickly and easily draw lines, circles, text and even display Images as well as play Video clips.

(GFX) 4DGL Platform: The (GFX) 4DGL-Platform modules are based on the PICASO-GFX2 Graphics Controller chip. In this mode, the PICASO-GFX2 becomes a standalone device and all application code is written in 4DGL (4D Graphics Language). Don't let the name scare you off, 4DGL is an easy to learn but a powerful high level language. It allows the developer to write applications in a high level syntax similar to popular languages such as BASIC, C and Pascal and run it directly on the PICASO-GFX2 processor. The (GFX) modules are stand alone devices. It allows the user to take complete control of all available resources on the module such as the Serial Port, the graphics display and the  micro-SD memory card. It provides the user complete control over the display module allowing them to offload a lot of overhead from the host processor by creating the 'work horse' objects within the display module itself.

NOTE: There is only a single PICASO chip on the module. The chip can be configured to be either a PICASO-SGC or a PICASO-GFX2 by programming the appropriate PmmC configuration file (Personality module micro Code) in to the chip. Think of it as a soft silicon where the silicon can be reconfigured via the PmmC file."

Would it be possible to please change the references from 4DGL to 4D SGC in your documentation, to avoid confusion for other users?

Thanks and regards, Anna.

user Stephane ROCHON
16 Nov 2010

Done. I will change the lib name and demo software later. Cheers !

user joby antony
02 Dec 2010

Stephane,

Will you please let me know what is status variable doing in "status = ecran.touch_status();" I see it returns sometimes 1 , sometimes 2 or 3 . I am unable to understand. pl. help.

Thanks antony

user Steve Woodruff
03 Dec 2010

awesome

user Daniel Garden
03 Dec 2010

Could you post a video please :-) very interesting library

user Stephane ROCHON
06 Dec 2010

user joby antony wrote:

Stephane,

Will you please let me know what is status variable doing in "status = ecran.touch_status();" I see it returns sometimes 1 , sometimes 2 or 3 . I am unable to understand. pl. help.

Thanks antony

Coming from the screen manual (p44) :

0 : No Touch Activity 1 : Touch Press 2 : Touch Release 3 : Touch Moving

The library supports all values.

So you get a 1 when you press the screen, a 2 when you remove your finger and a 3 if you move your finger while pressing the screen.

I need to spend some time to write the documentation.

Cheers,

user Stephane ROCHON
06 Dec 2010

user Daniel Garden wrote:

Could you post a video please :-) very interesting library

I will, I hope to find some time this week.

user J Antony
29 Dec 2010

Stephane, Thanks for above information. I have used your library for some touch panel buttons. It is useful.

But I have been facing a problem which is quite ununderstantable to me. I am using P9,p10 and p11(for reset) in this display. It works fine.

But whenever I put off the working display overnight and next day when I resume My work , the display doesn’t come on. Then I need to ON/OFF Vin power (+5 V SMPS Separate) many many times, then after trying many times, one time it may come on.

The time it comes “ON” is never predictable. Sometimes many many ON/OFF only makes it ON. Just after it is OFF , there is no surety it will come ON. Once it is ON , then no issues ,it gets reset from mbed button.

Also I noted that evenif I reset the mbed button during the problem times, then also it doesn’t come on for first time. Once it comes ON , then it behaves normal.

Is it any reset issue or my display has developed some problems. I don’t have a spare.

Thanks Antony

user joby antony
01 Jan 2011

Stephane, sorry for above query. it looks like it is a faulty display as it resets while pressing the pc board

user Stephane ROCHON
01 Jan 2011

Hello, sorry to hear that. Are you sure of the 5V and current value of your external power source ? I had screen erratic behaviour because there was not enough current to power it correctly.

Cheers

user Robert Spilleboudt
22 Feb 2011

Hello Stephane, Thanks for your lib: this is a nice first step for my new mbed. I am in trouble with the delays in writeBYTE (1ms) and in the write command ( while (!_cmd.readable()) wait_ms(TEMPO);). The technical documenation of 4D is pretty clear: theses delays are not needed. I tried to remove the delays ... without success. Why ? I do not know.
Then I wrote my own programs...without any delay.(not yet published but running )
When you check the ACK/NAK you have to abort or reset the display if the answer is different from ACK! This is needed because the wohle comunication is disturbed.
Cheers Robert

user stefan l
01 Apr 2011

wow, respect..very nice work :) can you show us some example programms? would be nice :)

Cheers Stefan

user Emmanuel Chio
18 Sep 2011

Hey I recently bought a new GREAT serial LCD board for development, like the LCD mentioned here, it just need TX and RX, and it have a plus, could be mounted on a standard breadboard to easy connect our mbeds! and the format it use is FAT(windows), 4D need strange formatting(I have test it), VERY EASY!

Check out also the videos!!!

Check out more here: http://mbed.org/cookbook/SMARTGPU

user Elias Breunig
18 Dec 2011

The lib seems not to work on a OLED 160 SGC Display from 4DGL... has anybody worked with those smaller displays?

user Dario Gogliandolo
12 Mar 2012

Sorry, this library is compatible with this LCD? http://shop.4dsystems.com.au/serial-display-modules/302-0004.html thanks