Brads Electronic Projects Forum

I understand this is an old project but may I ask if the Great Race schematic and software are correct, please? The schematic suggests that there's no way to really turn off all of the green LED rows which are connected to the 7442 outputs since one of those outputs will always be on (unless you decide to use the 7442 'D' input). So it seems whenever you turn on the red LED row one of the green LED rows will also be active and you'll light one green LED for each red LED that is lighted. Is this correct (and intentional?), or, is there a more up-to-date schematic and program listing, please?

TIA for any knowledgeable thoughtful replies...

Cheerful regards, Mike

Good pickup!

Although even though you always have a one column activated, So if you don't want any green to light up when you are drawing the car on the screen, you just need to make sure you send out all 1's to the green cathodes.

These days I like to use tri-state buffers though