Coding Badly,
Which requires exactly 16 MHz. Given the fact that the processor can execute exactly one operation (or fewer) per clock tick, how do plan to toggle the GSCLK signal at 16 MHz?
I was just trying to communicate to you I think my project is not beyond the AVR's ability... that 25kHz works with the UNO up to a mathematical maximum of 640 steps. I don't yet know how many steps I need, but it's a heck lot less than 640... just a few steps to take some temperature inputs and then talk the TLC5940 into changing the duty cycle for the respective channel at 10% increments. That is, fan speed 10%, 20%, ... 90%, 100%.
Which is 256 times slower than you need. Do you understand the difference between "MHz" and "kHz"? Do you understand how the TLC5940 works?
I need to shoot square 25kHz at the fan... That I know. No, I don't fully understand the TLC5940... it's a black box to me, but I understand it can expand UNO's capability to 16 channels (needed for 14 independant fans). Without using a TLC5940, I only have 2 maybe 3 channels from the UNO. Problem is (yes, because I don't understand theTLC5940... which is why I'm posting here) I don't know if the UNO must put out 25kHz to make the TLC5940 put out 25kHz. I had assumed the TLC5940 had it's own timer. I guess my assumption is wrong, but even so I didn't think it was a deal-breaker to make the UNO put out 25kHz...
But first you need to get your expectations in line with what the hardware is capable of doing.
Aside from the TLC5940, you now have me worried the UNO can't put out 25kHz itself like it appears in Arduino Playground - TimerPWMCheatsheet. I hadn't questioned the UNO's capability because it seems many people have successfully altered it's output frequency to drive one or two PWM fans anywhere from 16kHz to 32KHz. Have I fundamentally missed what those Arduinian's are doing?
Now I have NOT yet bought the UNO or TLC5940. If these components aren't correct to acheive my Goal, would you please suggest what is? I only require it be a digital 25kHz output (not analog).
-Thanks for your help in advance!