/* power saving mode, mcu runs significantly cooler    * Sysclock 240 Mhz, bus clocks 120 Mhz */  void SysClkHalfSpeed();  /* full speed - sysclk from PLL1 P - 480 Mhz   * Sysclock 480 Mhz, bus clocks 240 Mhz */  void SysClkFullSpeed()

#include <Arduino.h>#include <math.h>#include "whetstone.h"enum EnCpuSp {SPFULL = 0,SPHALF};void cpusetspeed(EnCpuSp speed);void checkcmd(void);void printtempvbat(void);void cosfade();void EnableCache();void sleep(uint16_t ms);int ledPin = LED_BUILTIN;int print = false;//used by cosfade()#define PER 15#define REP 20int8_t led = 0;int n = PER, cnt = 0;uint8_t p = 0;// the setup() method runs once when the sketch startsvoid setup() {EnableCache();//initialize the digital pin as an output:pinMode(ledPin, OUTPUT);digitalWrite(ledPin, LOW);pinMode(ATEMP, INPUT_ANALOG);pinMode(AVREF, INPUT_ANALOG);pinMode(USER_BTN, INPUT_PULLDOWN);}//the loop() method runs over and over again, void loop() {checkcmd();if (print && n == 0 && cnt == 0) printtempvbat();cosfade();}/* a half hearted attempt to make a 'breathing' led, works quite well though */void cosfade() {  digitalWrite(LED_BUILTIN,led);  led = ~led & 1;  if(led)    delay(PER-p);  else    delay(p);  if(cnt>REP) {  float nf, perf;  n = n>PER?0:n+1;  nf = n * 1.0;  perf = PER * 1.0;  p = perf * ( cos(2 * PI * nf/perf) / 2.0 + 0.5 );  cnt=0;  } else  cnt++;}void printtempvbat() {uint16_t vrefint = analogRead(AVREF);Serial.print("Vref int (1.21v):");Serial.print(vrefint);Serial.println();uint16_t vtemp = analogRead(ATEMP);Serial.print("temp sensor:");Serial.print(vtemp);Serial.println();uint16_t mv = (1210 * vtemp) / vrefint;Serial.print("mvolt:");Serial.print(mv);Serial.println();// specs 5.3.22 temp sensor characteristics// V 30 deg ~ 0.62v// slope 2 mv/Cuint16_t v30 = 620;float temp = (mv - v30) * 1.0 / 2.0 + 30.0;Serial.print("temp:");Serial.print(temp);Serial.println();}void cpusetspeed(EnCpuSp speed) {if (speed == EnCpuSp::SPHALF) {SysClkHalfSpeed();} else {SysClkFullSpeed();}}void checkcmd() {if(Serial.available()) {char r = Serial.read();if(r=='p') {print = ! print;} else if (r=='w') {//whetstone(F_CPU/1000000);whetstone(SystemCoreClock/1000000);} else if (r=='C') {cpusetspeed(EnCpuSp::SPFULL);Serial.print("sysclock Mhz:");Serial.println(SystemCoreClock/1000000);} else if (r=='c') {cpusetspeed(EnCpuSp::SPHALF);Serial.print("sysclock Mhz:");Serial.println(SystemCoreClock/1000000);} else {Serial.println("p - print/stop print");Serial.println("C - cpu full speed");Serial.println("c - cpu half speed");Serial.println("w - run whetstone");}}if (digitalRead(USER_BTN) == HIGH) {Serial.println("user btn pressed");}}void blinks() {for (int i = 0; i < 5; i++) {digitalWrite(LED_BUILTIN, HIGH);delay(100);digitalWrite(LED_BUILTIN, LOW);delay(100);}}void EnableCache() {SCB_CleanDCache();__DSB();SCB_InvalidateDCache();SCB_EnableDCache();__ISB();SCB_InvalidateICache();SCB_EnableICache();}void sleep(uint16_t ms) {for(uint16_t i=0; i<ms; i++)asm("wfi");}

p - print/stop printC - cpu full speedc - cpu half speedw - run whetstoneVref int (1.21v):376  <<< type 'p' print the cpu temperaturetemp sensor:205mvolt:659temp:49.50Beginning Whetstone benchmark at 480 MHz ...  <<< type 'w' run whetstone benchmarkLoops:10000, Iterations:1, Duration:1627.57 millisecC Converted Single Precision Whetstones:614.41 Mflopssysclock Mhz:240 <<< typed 'c' here to reduce system clock to 240 MhzVref int (1.21v):375temp sensor:205mvolt:661temp:50.50Beginning Whetstone benchmark at 240 MHz ...   <<< type 'w' run whetstone benchmarkLoops:10000, Iterations:1, Duration:3251.76 millisecC Converted Single Precision Whetstones:307.53 MflopsVref int (1.21v):376temp sensor:202mvolt:650temp:45.00user btn pressed  <<< --- press user button on boarduser btn presseduser btn pressed