| Rapid firing example, frequency = 50/12 = 4.17Hz

| Rapid-fire the return key when fire_1 is pressed.
| Uses a 4 bit counter giving a frequency of 4.17Hz,
| see the counter in operation using !JS_Test

|---------------------------------------------------

| Count from 0 to 11 using flagA_1,flagB_1,flagA_2,flagB_2
setA_1   = ~flagA_1
resetA_1 =  flagA_1
setB_1   = ~flagB_1.flagA_1
resetB_1 =  flagB_1.flagA_1
setA_2   = ~flagB_2.~flagA_2.flagB_1.flagA_1
resetA_2 =  flagA_2.flagB_1.flagA_1
setB_2   = ~flagB_2.flagA_2.flagB_1.flagA_1
resetB_2 =  flagB_2.~flagA_2.flagB_1.flagA_1

| Press return when fire pressed and count is 0 - 5
return   = fire_1.~flagB_2.~flagA_2 + fire_1.flagA_2.~flagB_1
