Scroll text on 7seg. digits with PMP

Well, I had to do it also for Pic Micro Pascal :) . It is the same project as here, the same boards and connection wires (schematic). The difference is in the language and finally, I did the movie which demonstrate zero "ghost" effect.

The schematic

See the link above.

The code

I ported the seven_segment Jallib library and it will be attached at the end of this page. In the program, apart of translation, I changed the text to suit. Again, no big deal in scrolling text on 7segments digits (I don't see it's use) but the same procedure applies to the more appropriate digits which permits indeed displaying the entire set of alphanumeric characters.

program scroll7seg;

{$PROCESSOR PIC18f2550}

{$FREQUENCY 48 MHZ}

{$OPTIMIZE MEMORY}

{$VECTORS RESET = $800, INT_HIGH = $808, INT_LOW = $818}

{$CONFIG OFF}

uses seven_segment,

tmr0_isr_interval;

const

  text_string: array[0..23] of byte = (// --27 is "Space" character

    27,27,27,23,10,16,12,10,21,27,    //--    PASCAL

    15,22,18,27,                      //-- For

    4,22,26,18,27,                    //-- Your

    26,12,27,27,27                    //-- uC

);

  leds_sequence: array[0..30] of byte = (

    0,1,3,7,15,31,63,127,255,254,252,248,240,224,192,128,0,// complete sequence

    128,192,224,240,248,252,255,127,63,31,15,7,3,1); //and reverse

var

  digits_buffer:array[0..3] of byte;

  //-- indices

  ix_text,ix_led: byte;

procedure PORTTEXT(x:byte); //7segments port: RB0 is segment a

begin                       // Dot segment is not connected

  LATB.0 := x.0;  //seg a

  LATB.1 := x.1;  //seg b

  LATB.2 := x.2;  //seg c

  LATB.3 := x.3;  //seg d

  LATB.4 := x.4;  //seg e

  LATB.5 := x.5;  //seg f

  LATB.6 := x.6;  //seg g

end;

procedure portA_low(x:byte);  //select digits

begin

  LATA.0 := x.0; // select digit nr.4 on EvB4.3 board

  LATA.1 := x.1; // select digit nr.3

  LATA.2 := x.2; // select digit nr.2

  LATA.3 := x.3; // select digit nr.1

end;

procedure show_digits;

begin

  PORTTEXT(seven_from_digit(27));

  portA_low(7);// -- 0b0111, digits are selectable with a 0 logic on my board

  PORTTEXT(digits_buffer[3]);

  delay(1500);

  //--

  PORTTEXT(seven_from_digit(27));

  portA_low(11); //-- 0b1011

  PORTTEXT(digits_buffer[2]);

  delay(1500);

  //--

  PORTTEXT(seven_from_digit(27));

  portA_low(13);// -- 0b1101

  PORTTEXT(digits_buffer[1]);

  delay(1500);

  //--

  PORTTEXT(seven_from_digit(27));

  portA_low(14); //-- 0b1110

  PORTTEXT(digits_buffer[0]);

  delay(1500);

  //--

end;

procedure update_buffer(id: byte);

begin

  digits_buffer[3] := seven_from_digit(text_string[id]);

  digits_buffer[2] := seven_from_digit(text_string[id + 1]);

  digits_buffer[1] := seven_from_digit(text_string[id + 2]);

  digits_buffer[0] := seven_from_digit(text_string[id + 3]);

end;

procedure PORTLED(x:byte);

begin             //FreeJALduino pinout

  LATC.7 := x.0;  //D0  LED nr.1

  LATC.6 := x.1;  //D1  LED nr.2

  LATA.4 := x.2;  //D2  LED nr.3

  LATB.7 := x.3;  //D10 LED nr.4

  LATC.0 := x.4;  //D11 LED nr.5

  LATC.1 := x.5;  //D12 LED nr.6

  LATC.2 := x.6;  //D13 LED nr.7

  LATA.5 := x.7;  //D18 LED nr.8

end;

//-------- START -------------

begin

  //-- Initializations

  TRISA := 0; // as output

  TRISB := 0;

  TRISC := 0;

  //adc_off

  ADCON0 := 0b00000000; // -- disable ADC

  ADCON1 := 0b00001111; // -- digital I/O

  ADCON2 := 0b00000000; //

  //comparator_off

  CMCON  := 0b00000111; // -- disable comparator

  //-- digits OFF

  portA_low(0b1111);

  timer0_isr_init; // -- init timer0 isr

  //-- init index

  ix_text := 0;

  ix_led  := 0;

  //-- fill the digits buffer

  update_buffer(ix_text);

  //-- start LED sequence

  PORTLED(leds_sequence[ix_led]);

  //-- set scroll speed for text

  set_delay(0, 300);

  //-- set scroll speed for LED's

  set_delay(1, 100);

  loop // instead of "while(1) do begin" - new feature ;)

    show_digits;

    if check_delay(0) then begin

      ix_text := ix_text + 1;

      if ix_text = 21 then

        ix_text := 0;

      update_buffer(ix_text);

      set_delay(0, 300);

    end;

    if check_delay(1) then begin

      ix_led := ix_led + 1;

      if ix_led = 31 then

        ix_led := 0;

      PORTLED(leds_sequence[ix_led]);

      set_delay(1, 100)

    end;

  end; //loop

end.

Note: It use also the timer0_isr_interval units which can be downloaded at the end of this page.