module tbirdsd 
title 'State Machine for T-Bird Tail Lights' 
"TBIRDSD device 'P16V8R'; 

" Input and output pins 
CLOCK, LEFT, RIGHT, HAZ, RESET   pin 1, 2, 3, 4, 5;
Q0, Q1, Q2                       pin 14, 15, 16 istype 'reg';

" Definitions 
QSTATE = [Q2,Q1,Q0];           " State variables 
IDLE   = [ 0, 0, 0];           " States 
L1     = [ 0, 0, 1]; 
L2     = [ 0, 1, 1]; 
L3     = [ 0, 1, 0]; 
R1     = [ 1, 0, 1]; 
R2     = [ 1, 1, 1]; 
R3     = [ 1, 1, 0]; 
LR3    = [ 1, 0, 0];

equations
QSTATE.CLK = CLOCK;

state_diagram QSTATE 
state IDLE: IF RESET THEN IDLE
            ELSE IF (HAZ # LEFT & RIGHT) THEN LR3
            ELSE IF LEFT THEN L1 ELSE IF RIGHT THEN R1
            ELSE IDLE; 
state L1:   IF RESET THEN IDLE ELSE IF HAZ THEN LR3 ELSE L2; 
state L2:   IF RESET THEN IDLE ELSE IF HAZ THEN LR3 ELSE L3; 
state L3:   GOTO IDLE; 
state R1:   IF RESET THEN IDLE ELSE IF HAZ THEN LR3 ELSE R2; 
state R2:   IF RESET THEN IDLE ELSE IF HAZ THEN LR3 ELSE R3; 
state R3:   GOTO IDLE; 
state LR3:  GOTO IDLE;

end tbirdsd