Max safe current output on a N64 controller port?

[nasune]

Well I'm trying to build a quick converter so that I can use a NGC controller on my N64. For this I'm using an arduino nano with a step up converter to provide the necessary 5v. From what I can gather the current on this would be around 20 mA (the nano is 19 mA and the step up converter's efficiency is 95%).
The thing is though, that I'm not sure how safe this is in the long run (ie will it blow out a controller port or worse after a couple of hours). Google is no help in this regard, so I'm hoping that someone here knows what the max safe current output is.

 

[FAST6191]

I doubt you will find such things done for any console really, never mind the N64. You would also have to wonder if each port is individually fed, and possibly also current limited, or if there is some kind of bus/rail. If it is individual (or with a current limiting resistor) then you might be able to tap power from two or more ports.

I have never heard of an N64 controller port being cooked, though at the same time I don't move in N64 circles too often and most don't do things like this that would cause it to be so.
Things to look at first.
Any official accessories?
Obvious starts are rumble packs and the GB adapter for the pokemon stadium games.

If you can measure the current draw during use of those then you can reasonably assume they are done such that 4 ports can fire them off at 100% duty cycle* (or whatever you detect) without issue.

*I have a few hesitations for the GB thing as it could be a ROM dumper or even a header checker+save dumper with minimal power on time. If you are measuring it should become apparent fairly quickly though. Equally my rather hazy memory of the thing had it booting fairly quickly, quicker than I would have expected 8Mbit + save to be dumped.

Option 2.
The cart slot itself. If you have one of those region adapters for your N64 you might be able to tap off the cart supply and those things are fairly beefy. I know it is not quite as nice as being able to rock up with a simple adapter cable. Equally if this is only for a prototype and you don't want to separately power it then once you have the proof of concept you can find something that works on 3.3V or less (there is some 1.8V programmable logic these days) and program it for that.

 

[nasune]

Thanks, I've just checked it and a controller plus memory pak draws about 23-24 mA so I should be safe (I'll check it first when the board comes in, the 19 mA is the official rating). It's not so much a prototype though, it's a minor adjustment to this project. (there are more precise libraries available, but for casual gaming this seems fine (plus I have no idea how to implement those libraries))
I know for sure it works for an uno r3 when powered by usb (and, at least for a short while, with a step up converter powered by the 3.3v) , but I want the nano for its smaller size and lower power consumption.
Once it works like I want it to, I'll print a nice case for it (either with an usb port for external power or, hopefully, with the converter).