| Rapid firing example, frequency = 50/4 = 12.5Hz

| Rapid-fire the return key when fire_1 is pressed.
| Uses a 2 bit counter giving a frequency of 12.5Hz,
| see the counter in operation using !JS_Test

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

| Count from 0 to 3 using flagA_1,flagB_1
setA_1   = ~flagA_1
resetA_1 =  flagA_1
setB_1   = ~flagB_1.flagA_1
resetB_1 =  flagB_1.flagA_1

| Press return when fire pressed and count is 0 - 1
return   = fire_1 . ~flagB_1
