UNO R3的时钟最快是多少？

set Timer2 的PWM输出频率到31kHz[code]/**************************************************************************************************
*
* PWM_Timer2_31kHz_00
*
* Version: 00 - Mai 2010
* Author: Tom Pawlofsky www.caad.arch.ethz.ch tom-DOT-pawlofsky-AT-arch-DOT-ethz-DOT-ch
*
* Desc: change prescaler of Timer 2 to have 31kHz Frequency at pin 3 and 11
*
***************************************************************************************************/
int pinA = 3; // pin 3 and 11 are PWM output controled by Timer2
int pinB = 11; // connect pinA/B to H-Bridge
void setup(){
//__________________________________TIMER2_for_Motor_PWM_________________________________
// set TIMER2 for PWM 32 Hz
//
// clear all prescaler bits in TCCR2B = the last 3 Bits
// leave other bits as set by arduino init() in wiring.c
byte mask = B11111000;
TCCR2B &= mask; // TCCR2B is now xxxxx000
//
// set CS22:20 in TCCR2B see p 156 of datasheet
TCCR2B |= (0<//__pinmode
pinMode(pinA,OUTPUT);
pinMode(pinB,OUTPUT);
//
}
void loop(){
analogWrite(pinA,128); // 50% Duty
analogWrite(pinB,32); //12.5 % Duty
}[/code]

应该是62.5ns

UNO 的pwm 频率可调。 默认500hz。

UNO 的时钟是16Mhz的。 所以，最快是6.25us。