This is a port of Henning Kralsen's UTFT library for Arduino/chipKIT to mbed, refactored to make full use of C++ inheritance and access control, in order to reduce work when implementing new drivers and at the same time make the code more readable and easier to maintain. As of now supported are SSD1289 (16-bit interface), HX8340-B (serial interface) and ST7735 (serial interface). Drivers for other controllers will be added as time and resources to acquire the displays to test the code permit.

# TFTLCD Library

NOTE (2013-03-25) Tested with both mbed LPC1768 and Freedom KL25Z. -todor

A TFT LCD driver library, which at the moment provides support for the following display controllers: HX8340-B (serial interface), SSD1289 (16-bit interface), ST7735-R (serial interface), ILI9325/ILI9328 (16-bit interface).

As I am acquiring and testing out new displays, I decided to combine all ported drivers into one library as with the original work done by Henning. However I also had as a goal to make the code maintenance and readability easier/better, so the code has been heavily refactored to make full use of C++ facilities as inheritance and access control. I extracted the common pieces of code into a base class, which every driver inherits and only the controller-specific side is provided in the actual driver - things like initialization, addressing, data transfer, etc.

Another nice extension is that the display's backlight can now be controlled through the driver. Either a simple on/off method of control could be selected, or the brightness can be set through use of PWM (the latter placing some restrictions on which pins can be used for this, as mbed offers hardware PWM on only 6 pins).

I also plan to add support for touch screens as part of the library. The goal is to grow this piece of software into a lightweight graphics widgets library, which can be used to construct control screens with buttons or menus in a speedy and intuitive way.

## Changes

### 2013-07-21

• Fixed the sleep/wake-up functions of the ILI9328 driver.

### 2013-06-15

• Added driver for ILI9328 (works with ILI9325) controller, 16-bit data bus. Screen rotation works as usual with the TFTLCD library, but for now only RGB565 color depth is working and you can use both 65K and 262K color space with this driver. But for some reason the sleep function is not behaving as expected; I am working on this.
• This is only on my to-do list for now - haven't really had the time yet - but I am going to refactor the library a bit to allow use of GPIO ports for data transfers instead of DigitalOut: faster and cleaner that way. For those who are using it already in a working design and cannot repurpose the pins anymore, the current way it's working will still be available; I am hoping not to tear up the public interfaces of the library (... too much). Anyway, since I am at it, I will also try to add support for multiple bus interfaces to drivers that support it (i.e. both 8bit and 16bit use of ILI932x or SSD1289). Thought this might be a good place to give you guys the heads-up.

### 2013-01-25

• Added PWM backlight control. If you intend to use this, please make sure that control pin is either one of p21, p22, p23, p24, p25, or p26, as only they support hardware PWM. Please be aware that the mbed pins do not have much juice behind them, so if your display's backlight requires a lot of current, you are better off interfacing through as small signal transistor or a MOSFET. For the rest please consult the updated Doxygen documentation. NOTE The addition of PWM-controlled backlight will not break your existing code, the new options have default values, which initialize the used driver to behave as prior to PWM. Only if you want to use the new feature, some changes need to be made. The PWM is configured to be 120Hz (period of 8.33 milliseconds), in order to avoid noticeable flicker in the backlight. If in your opinion this value is too fine, then you can reduce the frequency in the LCD constructor in <lcd_base.cpp> by increasing the period value. My recommendation is to avoid frequencies lower than 60Hz.

### 2012-12-21

• Internal-only changes in the way drivers transmit colors - done to simplify the bitmap drawing routines; client API remains unchanged.

### 2012-12-12

• Added the driver for the ST7735 display controller.
• Added the RGB18 color mode: choose between 16-bit (65K distinct colors) and 18-bit (262K distinct colors) color space [supported by all drivers]. NOTE This feature requires the image drawing functions to be changed, in order to account for differences between configured display color depth and the color depth of the image. Please review the API docs, in particular the new type bitmap_t and the DrawBitmap functions.
• Changed display rotation to be achieved through the correspondent settings in the respective controller registers: no more software translation between width and height in different display orientations.
• Extended the orientation options: PORTRAIT (top line to 12 o'clock/upright) and LANDSCAPE (top line to 9 o'clock) positions are the old options, PORTRAIT_REV (top line to 6 o'clock/upside-down) and LANDSCAPE_REV (top line to 3 o'clock) are the new orientations.
• Added more pre-defined colors: available now are COLOR_BLACK, COLOR_WHITE, COLOR_RED, COLOR_GREEN, COLOR_BLUE, COLOR_CYAN, COLOR_MAGENTA and COLOR_YELLOW.

### TODO

• Finish implementing PWM-controlled backlight (current-sink configuration).
• Add a driver for the HX8352-A controller (ITDB02-3.2WD 16:9 240x400 pixel resolution display).

## How to Use

The code is documented, so please review the API docs. There is a simple example to get you started...

## helpers.h

Committer:
ttodorov
Date:
2013-07-22
Revision:
27:26491d710e72
Parent:
5:09b6d228ceea

### File content as of revision 27:26491d710e72:

/** \file helpers.h
*  \brief Utility functions and macros.
*
* This library is based on the Arduino/chipKIT UTFT library by Henning
* Karlsen, http://henningkarlsen.com/electronics/library.php?id=52
*
* Copyright (C)2010-2012 Henning Karlsen. All right reserved.
*
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to:
*
* Free Software Foundation, Inc.
* 51 Franklin St, 5th Floor, Boston, MA 02110-1301, USA
*
*********************************************************************/
#ifndef TFTLCD_HELPERS_H
#define TFTLCD_HELPERS_H

#include "mbed.h"

/** \def HIGH
*  \brief User-friendly high pin level designation.
*/
#define HIGH                    1
/** \def LOW
*  \brief User-friendly low pin level designation.
*/
#define LOW                     0

/** \def swap( type, a, b )
*  \brief Convenience macro to swap two values.
*/
#define swap( type, a, b )      { type tmp = ( a ); ( a ) = ( b ); ( b ) = tmp; }

/** \def pulseLow( pin )
*  \brief Toggles a pin low, then high.
*/
#define pulseLow( pin )         pin = LOW; pin = HIGH

/** \def pulseHigh( pin )
*  \brief Toggles a pin high, then low.
*/
#define pulseHigh( pin )        pin = HIGH; pin = LOW

#ifndef ushort
typedef unsigned short ushort;
#endif

#endif /* TFTLCD_HELPERS_H */