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.

Dependents:   test SDCard capstone_display capstone_display_2 ... more

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

  • Replaced all existing fonts from the UTFT library with the free Terminus font. Two different sizes are provided: 8x12 pixels and 16x28 pixels. I found the old fonts not so good looking and then they supported only the ASCII codes in the range 30 (space) to 126 (the tilde ). The 7segment font didn't even implement anything else than the numbers from 0 to 9 - so it was unusable for anything (one couldn't even display the time or date as it lacked the colon [:] or the period [.] or the slash [/] or the space [ ] characters). So I completely revamped the fonts and added Terminus as the new default with its 2 sizes. Further more I added in both sizes most of the characters up to ASCII code 255. For any code not in there, the space character is substituted. In the case, when you already have provided your own fonts, please have a look at the API changes in the files <terminus.h> and <terminus.cpp>: I promise you whatever time you spent designing your own font, it is not wasted; you merely need to add a second array, which describes which ASCII codes are available in your font, and their byte offset in the original character bitmap array; and a struct to tie all parts together and describe the character size. I am sorry for breaking the old API, but you will like the change and new options it brings you. Now you can insert any char above 127 up to code 255 (if available, of course) with its hex representation, e.g displaying the current temperature would look something like 85\xB0 F or 26\xB0 C (the space in between degree and F or C is needed because both F and C are used in hex numbers, so \xB0F is interpreted as ASCII code 2831 instead of ASCII code 176, followed by the temperature scale denomination; if you insist on avoiding the space, you could write 85\xB0\x46 which will be displayed correctly as 85°F). You can either look up the ASCII code you need on Google or Bing, or just look at what's available - how it looks and its hex value - in the comments in <terminus.cpp>.
  • 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...

Committer:
ttodorov
Date:
Tue Dec 11 03:18:43 2012 +0000
Revision:
10:69571adcfad5
Parent:
9:58b328831d0a
Child:
12:d0978272a340
- preliminary support for using 18-bit colors

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ttodorov 9:58b328831d0a 1 /** \file st7735.h
ttodorov 9:58b328831d0a 2 * \brief mbed TFT LCD controller for displays with the ST7735 IC.
ttodorov 9:58b328831d0a 3 * \copyright GNU Public License, v2. or later
ttodorov 9:58b328831d0a 4 *
ttodorov 9:58b328831d0a 5 * A known display with this type of controller chip is the ITDB02-1.8SP
ttodorov 9:58b328831d0a 6 * from http://imall.iteadstudio.com
ttodorov 9:58b328831d0a 7 *
ttodorov 9:58b328831d0a 8 * This library is based on the Arduino/chipKIT UTFT library by Henning
ttodorov 9:58b328831d0a 9 * Karlsen, http://henningkarlsen.com/electronics/library.php?id=52
ttodorov 9:58b328831d0a 10 *
ttodorov 9:58b328831d0a 11 * Copyright (C)2010-2012 Henning Karlsen. All right reserved.
ttodorov 9:58b328831d0a 12 *
ttodorov 9:58b328831d0a 13 * Copyright (C)2012 Todor Todorov.
ttodorov 9:58b328831d0a 14 *
ttodorov 9:58b328831d0a 15 * This library is free software; you can redistribute it and/or
ttodorov 9:58b328831d0a 16 * modify it under the terms of the GNU Lesser General Public
ttodorov 9:58b328831d0a 17 * License as published by the Free Software Foundation; either
ttodorov 9:58b328831d0a 18 * version 2.1 of the License, or (at your option) any later version.
ttodorov 9:58b328831d0a 19 *
ttodorov 9:58b328831d0a 20 * This library is distributed in the hope that it will be useful,
ttodorov 9:58b328831d0a 21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
ttodorov 9:58b328831d0a 22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
ttodorov 9:58b328831d0a 23 * Lesser General Public License for more details.
ttodorov 9:58b328831d0a 24 *
ttodorov 9:58b328831d0a 25 * You should have received a copy of the GNU Lesser General Public
ttodorov 9:58b328831d0a 26 * License along with this library; if not, write to:
ttodorov 9:58b328831d0a 27 *
ttodorov 9:58b328831d0a 28 * Free Software Foundation, Inc.
ttodorov 9:58b328831d0a 29 * 51 Franklin St, 5th Floor, Boston, MA 02110-1301, USA
ttodorov 9:58b328831d0a 30 *
ttodorov 9:58b328831d0a 31 *********************************************************************/
ttodorov 9:58b328831d0a 32 #ifndef TFTLCD_ST7735_H
ttodorov 9:58b328831d0a 33 #define TFTLCD_ST7735_H
ttodorov 9:58b328831d0a 34
ttodorov 9:58b328831d0a 35 #include "lcd_base.h"
ttodorov 9:58b328831d0a 36
ttodorov 9:58b328831d0a 37 #ifdef __cplusplus
ttodorov 9:58b328831d0a 38 extern "C" {
ttodorov 9:58b328831d0a 39 #endif
ttodorov 9:58b328831d0a 40
ttodorov 9:58b328831d0a 41 /** Represents a LCD instance.
ttodorov 9:58b328831d0a 42 *
ttodorov 9:58b328831d0a 43 * This is the utility class, through which the display can be manipulated
ttodorov 9:58b328831d0a 44 * and graphics objects can be shown to the user. A known display, which
ttodorov 9:58b328831d0a 45 * works with this library is the ITDB02-1.8SP from iTeadStudio - a RGB TFT
ttodorov 9:58b328831d0a 46 * with 128x160 pixels resolution and 262K colors, using serail interface.
ttodorov 9:58b328831d0a 47 *
ttodorov 9:58b328831d0a 48 * The display needs 5 or 6 pins to work with mbed, uses +3.3V for backlight,
ttodorov 9:58b328831d0a 49 * power and logic, thus can be interfaced directly to the mbed kit without
ttodorov 9:58b328831d0a 50 * the need of shields or level shifters as with Arduino.
ttodorov 9:58b328831d0a 51 *
ttodorov 9:58b328831d0a 52 * How to use:
ttodorov 9:58b328831d0a 53 * \code
ttodorov 9:58b328831d0a 54 * // include the library, this will also pull in the header for the provided fonts
ttodorov 9:58b328831d0a 55 * #include "st7735.h"
ttodorov 9:58b328831d0a 56 *
ttodorov 9:58b328831d0a 57 * // create the lcd instance
ttodorov 9:58b328831d0a 58 * ST7735_LCD lcd( p14, p13, p12, p11, p10 ); // control pins
ttodorov 9:58b328831d0a 59 *
ttodorov 9:58b328831d0a 60 * int main()
ttodorov 9:58b328831d0a 61 * {
ttodorov 9:58b328831d0a 62 * // initialize display - place it in standard portrait mode and set background to black and
ttodorov 9:58b328831d0a 63 * // foreground to white color.
ttodorov 9:58b328831d0a 64 * lcd.Initialize();
ttodorov 9:58b328831d0a 65 * // set current font to the smallest 8x12 pixels font.
ttodorov 9:58b328831d0a 66 * lcd.SetFont( Font8x12 );
ttodorov 9:58b328831d0a 67 * // print something on the screen
ttodorov 9:58b328831d0a 68 * lcd.Print( "Hello, World!", CENTER, 25 ); // align text to center horizontally and use starndard colors
ttodorov 9:58b328831d0a 69 *
ttodorov 9:58b328831d0a 70 * while ( 1 ) { }
ttodorov 9:58b328831d0a 71 * }
ttodorov 9:58b328831d0a 72 *
ttodorov 9:58b328831d0a 73 * \endcode
ttodorov 9:58b328831d0a 74 * \version 0.1
ttodorov 9:58b328831d0a 75 * \author Todor Todorov
ttodorov 9:58b328831d0a 76 */
ttodorov 9:58b328831d0a 77 class ST7735_LCD : public LCD
ttodorov 9:58b328831d0a 78 {
ttodorov 9:58b328831d0a 79 public:
ttodorov 9:58b328831d0a 80 /** Creates a new instance of the class.
ttodorov 9:58b328831d0a 81 *
ttodorov 9:58b328831d0a 82 * \param CS Pin for the ChipSelect signal.
ttodorov 9:58b328831d0a 83 * \param RESET Pin for the RESET line.
ttodorov 9:58b328831d0a 84 * \param RS Pin for the RS signal.
ttodorov 9:58b328831d0a 85 * \param SCL Pin for the serial clock line.
ttodorov 9:58b328831d0a 86 * \param SDA Pin for the serial data line.
ttodorov 9:58b328831d0a 87 * \param BL Pin for controlling the backlight. By default not used.
ttodorov 9:58b328831d0a 88 */
ttodorov 9:58b328831d0a 89 ST7735_LCD( PinName CS, PinName RESET, PinName RS, PinName SCL, PinName SDA, PinName BL = NC );
ttodorov 9:58b328831d0a 90
ttodorov 9:58b328831d0a 91 /** Initialize display.
ttodorov 9:58b328831d0a 92 *
ttodorov 9:58b328831d0a 93 * Wakes up the display from sleep, initializes power parameters.
ttodorov 9:58b328831d0a 94 * This function must be called first, befor any painting on the
ttodorov 9:58b328831d0a 95 * display is done, otherwise the positioning of graphical elements
ttodorov 9:58b328831d0a 96 * will not work properly and any paynt operation will not be visible
ttodorov 9:58b328831d0a 97 * or produce garbage.
ttodorov 9:58b328831d0a 98 *
ttodorov 9:58b328831d0a 99 * \param oritentation The display orientation, landscape is default.
ttodorov 9:58b328831d0a 100 */
ttodorov 9:58b328831d0a 101 virtual void Initialize( orientation_t orientation = LANDSCAPE );
ttodorov 9:58b328831d0a 102
ttodorov 9:58b328831d0a 103 /** Puts the display to sleep.
ttodorov 9:58b328831d0a 104 *
ttodorov 9:58b328831d0a 105 * When the display is in sleep mode, its power consumption is
ttodorov 9:58b328831d0a 106 * minimized. Before new pixel data can be written to the display
ttodorov 9:58b328831d0a 107 * memory, the controller needs to be brought out of sleep mode.
ttodorov 9:58b328831d0a 108 * \sa #WakeUp( void );
ttodorov 9:58b328831d0a 109 * \remarks The result of this operation might not be exactly as
ttodorov 9:58b328831d0a 110 * expected. Putting the display to sleep will cause the
ttodorov 9:58b328831d0a 111 * controller to switch to the standard color of the LCD,
ttodorov 9:58b328831d0a 112 * so depending on whether the display is normally white,
ttodorov 9:58b328831d0a 113 * or normally dark, the screen might or might not go
ttodorov 9:58b328831d0a 114 * dark. Additional power saving can be achieved, if
ttodorov 9:58b328831d0a 115 * the backlight of the used display is not hardwired on
ttodorov 9:58b328831d0a 116 * the PCB and can be controlled via the BL pin.
ttodorov 9:58b328831d0a 117 */
ttodorov 9:58b328831d0a 118 virtual void Sleep( void );
ttodorov 9:58b328831d0a 119
ttodorov 9:58b328831d0a 120 /** Wakes up the display from sleep mode.
ttodorov 9:58b328831d0a 121 *
ttodorov 9:58b328831d0a 122 * This function needs to be called before any other, when the
ttodorov 9:58b328831d0a 123 * display has been put into sleep mode by a previois call to
ttodorov 9:58b328831d0a 124 * #Sleep( void ).
ttodorov 9:58b328831d0a 125 */
ttodorov 9:58b328831d0a 126 virtual void WakeUp( void );
ttodorov 9:58b328831d0a 127
ttodorov 9:58b328831d0a 128 protected:
ttodorov 9:58b328831d0a 129 /** Sends a command to the display.
ttodorov 9:58b328831d0a 130 *
ttodorov 9:58b328831d0a 131 * \param cmd The display command.
ttodorov 9:58b328831d0a 132 * \remarks Commands are controller-specific and this function needs to
ttodorov 9:58b328831d0a 133 * be implemented separately for each available controller.
ttodorov 9:58b328831d0a 134 */
ttodorov 9:58b328831d0a 135 virtual void WriteCmd( unsigned short cmd );
ttodorov 9:58b328831d0a 136
ttodorov 9:58b328831d0a 137 /** Sends pixel data to the display.
ttodorov 9:58b328831d0a 138 *
ttodorov 9:58b328831d0a 139 * \param data The display data.
ttodorov 9:58b328831d0a 140 * \remarks Sendin data is controller-specific and this function needs to
ttodorov 9:58b328831d0a 141 * be implemented separately for each available controller.
ttodorov 9:58b328831d0a 142 */
ttodorov 9:58b328831d0a 143 virtual void WriteData( unsigned short data );
ttodorov 9:58b328831d0a 144
ttodorov 9:58b328831d0a 145 /** Writes a single byte of pixel data to the display.
ttodorov 9:58b328831d0a 146 *
ttodorov 9:58b328831d0a 147 * \param data The data to be written.
ttodorov 9:58b328831d0a 148 * \remarks Sendin data is controller-specific and this function needs to
ttodorov 9:58b328831d0a 149 * be implemented separately for each available controller.
ttodorov 9:58b328831d0a 150 */
ttodorov 9:58b328831d0a 151 virtual void WriteByteData( unsigned char data );
ttodorov 9:58b328831d0a 152
ttodorov 9:58b328831d0a 153 /** Assigns a chunk of the display memory to receive data.
ttodorov 9:58b328831d0a 154 *
ttodorov 9:58b328831d0a 155 * When data is sent to the display after this function completes, the opertion will
ttodorov 9:58b328831d0a 156 * start from the begining of the assigned address (pixel position) and the pointer
ttodorov 9:58b328831d0a 157 * will be automatically incremented so that the next data write operation will continue
ttodorov 9:58b328831d0a 158 * with the next pixel from the memory block. If more data is written than available
ttodorov 9:58b328831d0a 159 * pixels, at the end of the block the pointer will jump back to its beginning and
ttodorov 9:58b328831d0a 160 * commence again, until the next address change command is sent to the display.
ttodorov 9:58b328831d0a 161 *
ttodorov 9:58b328831d0a 162 * \param x1 The X coordinate of the pixel at the beginning of the block.
ttodorov 9:58b328831d0a 163 * \param y1 The Y coordinate of the pixel at the beginning of the block.
ttodorov 9:58b328831d0a 164 * \param x2 The X coordinate of the pixel at the end of the block.
ttodorov 9:58b328831d0a 165 * \param y2 The Y coordinate of the pixel at the end of the block.
ttodorov 9:58b328831d0a 166 * \remarks Addressing commands are controller-specific and this function needs to be
ttodorov 9:58b328831d0a 167 * implemented separately for each available controller.
ttodorov 9:58b328831d0a 168 */
ttodorov 9:58b328831d0a 169 virtual void SetXY( uint16_t x1, uint16_t y1, uint16_t x2, uint16_t y2 );
ttodorov 9:58b328831d0a 170
ttodorov 10:69571adcfad5 171 /** Sets the color of the pixel at the address pointer of the controller.
ttodorov 10:69571adcfad5 172 *
ttodorov 10:69571adcfad5 173 * This function is to be provided by each implementation separately in
ttodorov 10:69571adcfad5 174 * order to account for different color depth used by the controller.
ttodorov 10:69571adcfad5 175 * \param color The color of the pixel.
ttodorov 10:69571adcfad5 176 */
ttodorov 10:69571adcfad5 177 virtual void SetPixelColor( unsigned short color );
ttodorov 10:69571adcfad5 178
ttodorov 9:58b328831d0a 179 private:
ttodorov 9:58b328831d0a 180 void serializeByte( unsigned char data );
ttodorov 9:58b328831d0a 181
ttodorov 9:58b328831d0a 182 private:
ttodorov 9:58b328831d0a 183 DigitalOut _lcd_pin_scl, _lcd_pin_sda;
ttodorov 9:58b328831d0a 184 DigitalOut* _lcd_pin_bl;
ttodorov 9:58b328831d0a 185 };
ttodorov 9:58b328831d0a 186
ttodorov 9:58b328831d0a 187 #ifdef __cplusplus
ttodorov 9:58b328831d0a 188 }
ttodorov 9:58b328831d0a 189 #endif
ttodorov 9:58b328831d0a 190
ttodorov 9:58b328831d0a 191 #endif /* TFTLCD_ST7735_H */