GCBASIC documentation
GLCD Overview

This section covers Graphical Liquid Crystal Display (GLCD) devices that use the Toshiba T6963 graphics controller.   The T6963 is a monochrome device that typically is blue or white.   The GLCD can be provided in a number of pixels sizes - 240 * 64 or 240 * 128.

The Toshiba T6963 is a very popular LCD controller for use in small graphics modules. It is capable of controlling displays with a resolution up to 240x128. Because of its low power and small outline it is most suitable for mobile applications such as PDAs, MP3 players or mobile measurement equipment.

A number of GLCD modules have this controller built-in these include the SP12N002 & SP14N001. Although this controller is small, it has the capability of displaying and merging text and graphics and it manages all the interfacing signals to the displays Row and Column drivers.   The GCBASIC library supports the complex capabilities of the T6963.

The T6963 is an LCD is driven by on-board 5V parallel interface chipset T6963.   For the specific operating voltage always verify the operating voltages in the device specific datasheet.

The GCBASIC connectivity option is the 8-bit mode - where 8 connections (for the data) are required between the microcontroller and the GLCD to control the data bus.

To use the T6963 driver simply include the following in your user code.    This will initialise the driver.

    #chip 16f1939,32
    #option explicit

    '***********************************************************************************************
    'Specify this GLCD - a 240 x 64 pixels display
    #include <glcd.h>
     #define GLCD_TYPE GLCD_TYPE_T6963_64

    '***********************************************************************************************
    'define the connectivity - the 8bit port
    #define GLCD_DATA_PORT PORTD             'Library support contigous 8-bit port

  '  or
  '  #define GLCD_DB0      PORTD.0            'chip specific configuration where the ibrary supports 8-bit port defined via 8 constants
  '  #define GLCD_DB1      PORTD.1            'chip specific configuration
  '  #define GLCD_DB2      PORTD.2            'chip specific configuration
  '  #define GLCD_DB3      PORTD.3            'chip specific configuration
  '  #define GLCD_DB4      PORTD.4            'chip specific configuration
  '  #define GLCD_DB5      PORTD.5            'chip specific configuration
  '  #define GLCD_DB6      PORTD.6            'chip specific configuration
  '  #define GLCD_DB7      PORTD.7            'chip specific configuration

     #define GLCD_CS        PORTa.7           'Chip Enable (Active Low)
     #define GLCD_CD        PORTa.0           'Command or Data conrol line port
     #define GLCD_RD        PORTA.1           'Read control line  port
     #define GLCD_WR        PORTA.2           'Write control line port
     #define GLCD_RESET     PORTA.3           'Reset port
     #define GLCD_FS        PORTA.5           'FS port
     #define GLCD_FS_SELECT 1                 'FS1 Font Select port. 6x8 font: FS1=“High”=1 8x8 font FS1=“Low”=0 for GLCD_FS_SELECT

    '***********************************************************************************************
    '*
    '* Note    :   The T6963 controller's RAM address space from $0000 - $7FFF, total 32kbyte RAM, or it could be 64kbyte RAM best check!!
    '*
    '***********************************************************************************************
     #define TEXT_HOME_ADDR      0x0000                                                         'This is specific to the GLCD display
     #define GRH_HOME_ADDR       0x3FFF                                                         'This is specific to the GLCD display
     #define CG_HOME_ADDR        0x77FF                                                         'This is specific to the GLCD display
     #define COLUMN              40    'Set column number to be 40 , 32, 30 etc.                 This is specific to the GLCD display
     #define MAX_ROW_PIXEL       64    'MAX_ROW_PIXEL the physical matrix length (y direction)   This is specific to the GLCD display
     #define MAX_COL_PIXEL       240   'MAX_COL_PIXEL the physical matrix width (x direction)    This is specific to the GLCD display

    '***********************************************************************************************
    '* End of configuration
    '***********************************************************************************************

The GCBASIC constants for the interface to the controller are shown in the table below.

The T6963 differs from most other GLCD controllers in its use of the display RAM.    Where a fixed area of memory is normally allocated for text, graphics and the external character generator, but with the T6963 the size for each area MUST be set by software commands.    This means that the area for text, graphics and external character generator can be freely allocated within the external memory, up to 64 kByte.   Check the specific device for the amount of memory available.   This can range from 4 kbyte to 64 kbyte.

For more information on memory management refer the device specific datasheet.

The GCBASIC constants control the memory configuration of the T6963 controller.

The GCBASIC library supports the following capabilities.   Please refer to the relevant Help section and the device specific demonstrations.

Commands Supported for the LCD and GLCD

The GLCD command set covers the standard GLCDCLS, Line, Circle and all the GLCD methods and the LCD command set: CLS, Locate, Print, LCDHEX etc. The demonstrations show how to load BMP loading via external data sources and GLCD and LCD page swapping.

The table below shows the specific implementations of the command set for this device.   Refer to the GLCD and LCD in the Help for the generic GLCD and LCD commands.

GLCD and LCD page swapping

To support GLCD and LCD page swapping - this can be used to support fixed pages of information, BMPs or scrolling the following constants have are available to the user.

For GLCD memory addressing

  GLCDPage0_T6963
  GLCDPage1_T6963
  GLCDPage2_T6963
  ... etc
  GLCDPage10_T6963

Ten pages are automatically created but the number of pages available is constrained by the memory configuration.

For LCD memory addressing

  LCDPage0_T6963
  LCDPage1_T6963
  LCDPage2_T6963
  ...etc
  LCDPage10_T6963

Ten pages are automatically created but the number of pages available is constrained by the memory configuration.
To use add the following to you user program.   See the demonstration programs for more detailed usage.   After calling the SelectGLCDPage or SelectLCDPage methods all GLCD or LCD commands will be applied to the current GLCD or LCD page.

    'Select the GLCD page 1 memory
    SelectGLCDPage ( GLCDPage1_T6963 )

    'Select the LCD page 2 memory
    SelectLCDPage ( LCDPage2_T6963 )

The SelectLCDPage and SelectLCDPage and "Set Text Home Address" methods change the screen being viewed on the device.

The key is to establish what you want your memory map to look like.     Below is a map for one of my 240 x 64 pixel device.     The default is for 10 screen pages (some newer LCD’s may have more RAM for more screens).     If you write the appropriate value (0x1000, or 0x11b0, or 0x1360, etc) to the text home address, the display will instantly change to that screen - using SelectLCDPage and SelectLCDPage method with the appropiate constant as parameter.

You can write your screens "ahead of time", in my case during the "splash screen" delay interval, and instantly change to them later as desired.     You can do this by setting current_grh_home_addr to the appropiate page.    And, then execute the GLCD commands you would normal use.

The graphic and text screens are independant but can be overlaid for a variety of useful effects.

Although, not tested, the LCD text screens can be scrolled 1 full text line at a time, while the GLCD screens can be scrolled 1 pixel row at a time, provided you’ve set up your memory map accordingly with adequate RAM for the graphic area.

Default Memory Map

            '
            '*******************************************************
            '
            ' LCD MEMORY MAP
            '
            '*******************************************************
            '
            '
            '
            ' --------------------
            ' |                  | 0x0000
            ' |                  |
            ' | TEXT RAM AREA    | Each page has the numnbers of bytes + extra
            ' | ( 10 SCREENs )   | few bytes need to attributes. This is
            ' |                  | mentioned in the datasheet but imperical
            ' |                  | testing shows... you need the extra bytes
            ' --------------------
            ' |                  |
            ' | xx bytes unused  |
            ' |                  |
            ' --------------------
            ' |                  | 0x3fff
            ' |                  |
            ' |                  |
            ' |  GCLD RAM AREA   |
            ' |  ( 10 SCREENS )  |
            ' |                  |
            ' |                  |
            ' |          |
            ' --------------------
            ' |                  | 0x77ff
            ' |   CG RAM AREA    | (Sacrosanct)
            ' |                  |
            ' -------------------- 0x7ffff
            '

Other methods and constants
There are many other methods and constants that support this device.   Reviewing the library will assist in understanding how these private methods and constants support the overal solution for this library.

For more help, see GLCDCLS, GLCDDrawChar, GLCDPrint or Pset

Supported in <GLCD.H>