-- --------------------------------------------------------------------------
-- count_11LED.jal - 11-bit binary counter
-- $Id: count_11LED.jal,v 1.1 2003/03/04 16:58:12 jerry Exp $
-- $Source: /home/cvsroot/projectsTop/picProjectBoard/examples/count_11LED.jal,v $
-- 
-- --------------------------------------------------------------------------
-- A binary count is displayed on D1-D4 and the first column of U5 (or
-- U6).
-- --------------------------------------------------------------------------

include f877_20
include jlib     

disable_a_d_functions

pin_c0_direction = output
pin_c1_direction = output
pin_c2_direction = output
pin_c3_direction = output

-- control lines for the 5x7 display
-- port D controls the rows, port B the columns
port_d_direction = all_output
pin_b0_direction = output
pin_b1_direction = output
pin_b2_direction = output
pin_b3_direction = output
pin_b4_direction = output

var byte count_low
var byte count_high

count_low = 0
count_high = 0

-- a zero on the control line in port_b enables the column of LEDs
port_b = ! 1

forever loop
  count_low = count_low + 1
  if count_low > 15
  then
    count_low = 0
    count_high = count_high + 1
    if count_high > 127
    then
      count_high = 0
    end if
  end if

  -- LEDs D1-D4 are 'on' when the assoicated bit in port C is 0, so invert the
  -- count before writing it to the port.
  port_c = ! count_low
  port_d = count_high
  delay_1ms( 10 )
end loop