Scroll text on 4 seven-segment digits

The example use two main libraries: seven_segment.jal for code numbers and letters, and timer0_isr_interval.jal for multitasking simulation. The movie below does not illustrate the last version of the program, so, the "ghost" effect is still obvious. Maybe I'll update the movie some day...

The scrolled text is: "HELLO JOEP AND VASILE _ THIS USE Your LibrArY"

Click on image to zoom

Digit schematic (both digit select and segment select active on 0 logic). Also, on my board(EvB 4.3), the 8 LEDs are active on 0 logic (common anode) but on your board can be common cathode if you want.

Click on image to zoom

The free terminals of the LEDs and transistors are connected to Vcc. I don't know the values of resistors from transistors base and segments (are SMD on my board) but for LEDs you can have values between 330R and 470R. As you can see, no pin has remained free on the FreeJALduino board ([Analog 5] and [AREF] pins are not connected) so, dot segments are left unconnected.

The code:

-- Scroll text on 4 seven_segment digits using

-- FreeJALduino and EvB 4.3 boards.

-- Copyright Vasile Guta Ciucur

-- New BSD License

include freejalduino4

const bit seven_segment_common_anode = true

include seven_segment

include delay

const dword timer0_isr_rate = 1000 -- 1 kHz isr rate

const DELAY_SLOTS = 2 -- one timing for scroll speed and another

                      -- for blinking LED's

include timer0_isr_interval

-- DECLARATIONS

-- The text displayed: "   HELLO JOEP AND VASILE _ THIS USE Your LibrArY   "

-- See "seven_segment.jal" library for corresponding codes

const byte text_string[] = { --27 is "Space" character

   27,27,27,19,14,21,21,0,27, --    HELLO

   28,0,14,23,27,             -- JOEP

   10,29,13,27,               -- And

   24,10,16,1,21,14,27,       -- UASILE

   32,27,                     -- _

   7,19,1,16,27,              -- THIS

   24,16,14,27,               -- USE

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

   21,20,11,18,10,18,4,27,27,27} -- LibrArY

-- the sequence for LED's

const byte leds_sequence[] = {

   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

-- the buffer for the 4 digits - the data contained here is

-- permanently displayed on digits.

var byte digits_buffer[4]

-- indices

var byte ix_text

var byte ix_led

procedure PORTTEXT'put(byte in x) is

  var volatile bit x_0 at x:0

  var volatile bit x_1 at x:1

  var volatile bit x_2 at x:2

  var volatile bit x_3 at x:3

  var volatile bit x_4 at x:4

  var volatile bit x_5 at x:5

  var volatile bit x_6 at x:6

  D3 = x_0

  D4 = x_1

  D5 = x_2

  D6 = x_3

  D7 = x_4

  D8 = x_5

  D9 = x_6

end procedure

procedure show_digits is

  PORTTEXT = seven_from_digit(27)

  portA_low =  7 -- 0b0111, digits are selectable with a 0 logic on my board

  PORTTEXT = digits_buffer[3]

  delay_10us(150)

--

  PORTTEXT = seven_from_digit(27)

  portA_low = 11 -- 0b1011

  PORTTEXT = digits_buffer[2]

  delay_10us(150)

--

  PORTTEXT = seven_from_digit(27)

  portA_low = 13 -- 0b1101

  PORTTEXT = digits_buffer[1]

  delay_10us(150)

--

  PORTTEXT = seven_from_digit(27)

  portA_low = 14 -- 0b1110

  PORTTEXT = digits_buffer[0]

  delay_10us(150)

--

end procedure

procedure update_buffer(byte in id) is

  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

procedure PORTLED'put(byte in x) is

  var volatile bit x_0 at x:0

  var volatile bit x_1 at x:1

  var volatile bit x_2 at x:2

  var volatile bit x_3 at x:3

  var volatile bit x_4 at x:4

  var volatile bit x_5 at x:5

  var volatile bit x_6 at x:6

  var volatile bit x_7 at x:7

  D0 = x_0

  D1 = x_1

  D2 = x_2

  D10 = x_3

  D11 = x_4

  D12 = x_5

  D13 = x_6

  D18 = x_7

end procedure

-- START = Ready, Steady, GO!

-- Initializations

timer0_isr_init() -- init timer0 isr

enable_digital_io()

portA_direction = Output

portB_direction = Output

portC_direction = Output

-- digits OFF

portA_low = 0b1111

-- 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)

forever loop

  show_digits

  if check_delay(0) then

    ix_text = ix_text + 1

    if ix_text == 48 then

      ix_text = 0

    end if

    update_buffer(ix_text)

    set_delay(0, 300)

  end if

  if check_delay(1) then

    ix_led = ix_led + 1

    if ix_led == 31 then

      ix_led = 0

    end if

    PORTLED = leds_sequence[ix_led]

    set_delay(1, 100)

  end if

end loop