' -------------------------------------------------------------------------
' Program Description
' -------------------------------------------------------------------------
'
' Demonstrates FOR-NEXT loops in SX/B with a "ping-pong" LED display.

' -------------------------------------------------------------------------
' Device Settings
' -------------------------------------------------------------------------

DEVICE          SX28, OSC4MHZ, TURBO, STACKX, OPTIONX
FREQ            4_000_000
ID              "FOR-NEXT"

' -------------------------------------------------------------------------
' IO Pins
' -------------------------------------------------------------------------

LEDs            VAR     RB                      ' LED outputs
TRIS_LEDs       VAR     TRIS_B

' -------------------------------------------------------------------------
' Variables
' -------------------------------------------------------------------------

idx             VAR     Byte                    ' loop counter

' =========================================================================
  PROGRAM Start
' =========================================================================

' -------------------------------------------------------------------------
' Program Code
' -------------------------------------------------------------------------

Start:
  TRIS_LEDs = %00000000                         ' make LED pins outputs

Main:
  DO
    FOR idx = 0 TO 5                            ' loop 7 times
      LEDs = 1 << idx                           ' LEDs = 1, 2, 4, 8, ...
      PAUSE 100                                 ' pause 100 ms
    NEXT
    FOR idx = 7 TO 1 STEP -1                    ' loop 7 times
      LEDs = 1 << idx                           ' LEDs = 128, 64, 32 ...
      PAUSE 100                                 ' pause 100 ms
    NEXT
  LOOP                                          ' repeat forever