Adding SNES Input..

speewave

Well i'm looking at the Hydra Book (CH 6.)
( http://www.parallax.com/dl/docs/prod/prop/hydra-ch6all-v1.0.pdf )

the schematics for NES adapter has a 3.3v line in put to the 5v pin but will it still work?

the 4021 is a CMOS device and works
fine at 3.3 V. Of course, running any CMOS device rated for 3-7 V at lower voltages lowers
the maximum clocking rate, but in this context it’s irrelevant, since we can read the controller
bits at a rate of 200 ns each.

now what i was wondering is that can SNES Controllers still be read at 200ns / controller?

They are both identical, however SNES has a 16bit output, the NES having an 8bit output

whicker

I think you're missing the point.

The point is not to read the controller at the maximum 200nS clocking rate. It's that the code can clock the controller at a much slower rate than 200nS.

1,000,000 nS = 1,000 uS = 1 mS

The majority of games polled the controller maximum 60 times a second, that's a burst of clocks every 16.66 mS.

Lets say 18 ticks of 200nS (latch, 16 clocks, unlatch). 18 * 200nS = 3.6 microseconds. 1/ 3.6 uS (same as 1 / 0.0000036) = 277,777 times a second.

There's no reason to read that fast.
your buttons will bounce on and off for at least a couple of milliseconds anyway.

speewave

ok... thanks for clearing that up!

i've never dealt with controllers at the hardware level.