PCD8544 Controllers

This section covers GLCD devices that use the PCD844 graphics controller.

The PCD8544 is a low power CMOS LCD controller/driver, designed to drive a graphic display of 48 rows and 84 columns. All necessary functions for the display are provided in a single chip, including on-chip generation of LCD supply and bias voltages, resulting in a minimum of external components and low power consumption. The PCD8544 interfaces to microcontrollers through a serial bus interface.

The Great Cow BASIC constants shown below control the configuration of the PCD844 controller.    Great Cow BASIC supports SPI software connectivity only - this is shown in the tables below.

The PCD8544 is a monochrome device.

The PCD844can operate in two modes. Full GLCD mode and Text/JPG mode the full GLCD mode requires a minimum of 512 bytes. For microcontrollers with limited memory the text only can be selected by setting the correct constant.

To use the PCD844 driver simply include the following in your user code. This will initialise the driver.

    #include <glcd.h>
    #define GLCD_TYPE GLCD_TYPE_PCD8544

    ' Pin mappings for software SPI for Nokia 3310 Device
    #define GLCD_DO     portc.5              'example port setting
    #define GLCD_SCK    portc.3              'example port setting
    #define GLCD_DC     portc.2              'example port setting
    #define GLCD_CS     portc.1              'example port setting
    #define GLCD_RESET  portc.0              'example port setting

The Great Cow BASIC constants for the interface to the controller are shown in the table below.

Constants Controls Options

GLCD_TYPE

GLCD_TYPE_PCD8544

 

GLCD_DC

Specifies the output pin that is connected to Data/Command IO pin on the GLCD.

Required

GLCD_CS

Specifies the output pin that is connected to Chip Select (CS) on the GLCD.

Required

GLCD_Reset

Specifies the output pin that is connected to Reset pin on the GLCD.

Required

GLCD_D0

Specifies the output pin that is connected to Data Out (GLCD in) pin on the GLCD.

Required

GLCD_SCK

Specifies the output pin that is connected to Clock (CLK) pin on the GLCD.

Required

The Great Cow BASIC constants for control display characteristics are shown in the table below.

Constants Controls Default

GLCD_TYPE_PCD8544_CHARACTER_MODE_ONLY

Specifies that the display controller will operate in text mode and BMP draw mode only.
For microcontrollers with less then 1kb of RAM this will be set be default.

Optional

PCD8544ClockDelay

Specifies the clock delay, if required for slower microcontroller,

Optional. Set to 0 as the default value

PCD8544WriteDelay

Specifies the write delay, if required for slower microcontroller,

Optional. Set to 0 as the default value

GLCD_WIDTH

The width parameter of the GLCD

160
This cannot be changed

GLCD_HEIGHT

The height parameter of the GLCD

128
This cannot be changed

GLCDFontWidth

Specifies the font width of the Great Cow BASIC font set.

6

The Great Cow BASIC commands supported for this GLCD are shown in the table below.   Always review the appropiate library for the latest full set of supported commands.

Command Purpose Example

GLCDCLS

Clear screen of GLCD

GLCDCLS

GLCDPrint

Print string of characters on GLCD using GCB font set

GLCDPrint( Xposition, Yposition, Stringvariable )

GLCDDrawChar

Print character on GLCD using GCB font set

GLCDDrawChar( Xposition, Yposition, CharCode )

GLCDDrawString

Print characters on GLCD using GCB font set

GLCDDrawString( Xposition, Yposition, Stringvariable )

Box

Draw a box on the GLCD to a specific size

Box ( Xposition1, Yposition1, Xposition2, Yposition2, [Optional In LineColour as 0 or 1] )

FilledBox

Draw a box on the GLCD to a specific size that is filled with the foreground colour.

FilledBox (Xposition1, Yposition1, Xposition2, Yposition2, [Optional In LineColour 0 or 1] )

Line

Draw a line on the GLCD to a specific length that is filled with the specific attribute.

Line ( Xposition1, Yposition1, Xposition2, Yposition2, [Optional In LineColour 0 or 1] )

PSet

Set a pixel on the GLCD at a specific position that is set with the specific attribute.

PSet(Xposition, Yposition, Pixel Colour 0 or 1)

GLCDWriteByte

Set a byte value to the controller, see the datasheet for usage.

GLCDWriteByte ( LCDByte)

GLCDReadByte

Read a byte value from the controller, see the datasheet for usage.

bytevariable = GLCDReadByte

*For a PCD8544 datasheet, please refer here

This example shows how to drive a PCD8544 based Graphic LCD module with the built in commands of Great Cow BASIC.

Example:

    #chip 16lf1939,32
    #config Osc = INT, MCLRE_ON, PLLEN_Off, CLKOUTEN_OFF

        #include <glcd.h>

        #DEFINE GLCD_TYPE GLCD_TYPE_PCD8544

          ' Pin mappings for software SPI for Nokia 3310 Device
              #define GLCD_DO portc.5
              #define GLCD_SCK portc.3
              #define GLCD_DC portc.2
              #define GLCD_CS portc.1
              #define GLCD_RESET portc.0


          GLCDCLS

          DO forever
             for CCount = 31 to 127
                  GLCDPrint (0, 0, "PrintStr")
                  GLCDDrawString (0, 9, "DrawStr")
                  GLCDPrint ( 44 ,  21, "     ")
                  GLCDPrint ( 44 ,  29, "     ") ' word value
                  GLCDPrint ( 44 ,  37, "   ") ' Byte value

                  outstring = hex( longNumber_U)
                  GLCDPrint ( 44 , 21,outstring )
                  outstring = hex( longNumber_H)
                  GLCDPrint ( 55 , 21, outstring)
                  outstring = hex( longNumber)
                  GLCDPrint ( 67 , 21,  outstring )
                  GLCDPrint ( 44 , 29, mid( str(wordNumber),1, 6))
                  GLCDPrint ( 44 , 37, byteNumber)

                  box 46,9,57,19
                  GLCDDrawChar(48, 9, CCount )
                  outString = str( CCount )
                  ' draw a box to overwrite existing strings
                  FilledBox(58,9,GLCD_WIDTH-1,17,GLCDBackground )
                  GLCDDrawString(58, 9, outString )

                   box 0,0,GLCD_WIDTH-1, GLCD_HEIGHT-1
                   box GLCD_WIDTH-5, GLCD_HEIGHT-5,GLCD_WIDTH- 1, GLCD_HEIGHT-1
                   filledbox 2,30,6,38, wordNumber
                   Circle( 25,30,8,1)            ;center
                   FilledCircle( 25,30,4,longNumber xor 1) ;center

                   line 0,  GLCD_HEIGHT-1 , GLCD_WIDTH/2, (GLCD_HEIGHT /2) +1
                   line  GLCD_WIDTH/2, (GLCD_HEIGHT /2) +1 ,0, (GLCD_HEIGHT /2) +1


                  longNumber = longNumber + 7
                  wordNumber = wordNumber + 3
                  byteNumber++
              NEXT
          LOOP

      end

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

Supported in <GLCD.H> and <glcd_PCD8544.h>