A Strange Query - NES Power LED

Jonny

Well-known member
This is a very odd question I know which is why it's in randomness aimed at anyone who knows a lot about NES hardware.
So... my question is can the LED be controlled by programming on the cart? i.e can it be make to flash at will. I thought of a cool idea for my game, but of course its not essental so I didn't want to post this as a request for help. Just curious mainly.
I've done some searching online, but I only get "how to fix blinking light" pages.

You can all have a good laugh about how dumb this question is now lol.
 

Knietfeld

Member
I don't know the answer but I think it's a pretty interesting question. I tried searching for a few minutes but probably found the same stuff as you. I don't have a cart flasher or test cart or I would try some stuff. But I'm guessing the only reason the light turns off is when the cartridge and system aren't connecting properly so it cycles power to see if it's gonna work or not. Now you've got me imagining a game that trolls you by making you think it messed up and reset itself.
 

Jonny

Well-known member
Now you've got me imagining a game that trolls you by making you think it messed up and reset itself.
Trying to not give away any spoilers but that's almost exactly why I was asking. Anyone who reads this will propably have forgotten by the time my game is done though or not care hopefully. I keep meaning to learn properly about hardware. Another idea would be to have an LED on the cart itself, although it wouldn't be seen in a lot of systems, only top loaders. Maybe I should concentrate on making the actual game lol.
 

charliee

New member
If you are referring to the LED on the original NES console (flip top, takes large cartridge), the answer is "probably not". The led is not set up as a typical "power controlled" LED which simply turns on when power is applied. This itself is a bit obvious as anyone who has had a Reset issue, or a bad/misaligned cartridge, will know that the LED also blinks under that condition.

The LED is controlled by the CIC chip, which you may be aware is the "lockout" chip that the NES uses to validate proper cartridges (game region, cloned cart, etc). This chip is itself a CPU, and as such is performing the duties it is programmed with. IIRC, there was no "blink LED on command" programming within it. As a caveat to that statement, I did not pursue digging deeper into that chip once I had gotten the timing/reset method determined, so I do not know if the connections between the NES CPU and the CIC chip allow programming (re-programming) the chip to make it respond to a blink-on-demand command.

Cool idea, tho.

Charlie
 
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