RESET reason found out

[kendo55]

on esp8266 we had the opportunity to ask for the RESET reason after reboot.
is there an equivalent on PICO?

on esp8266

rst_info *resetInfo;
resetInfo = ESP.getResetInfoPtr();
uint16_t reset_reason = resetInfo->reason;

"0 Power reboot\n"
"1 Hardware WDT reset\n"
"2 Fatal exception\n"
"3 Software watchdog reset\n"
"4 Software reset\n"
"5 Deep-sleep\n"
"6 Hardware reset\n";

[earlephilhower]

Because things like WDT and reset are all HW driven and not really Arduino core related, I think you will have better luck on the RPI forums or Pico-SDK repo.

[kendo55]

my proposal for a additional function in the RP2040 Helper Class

void rp2040.resetReason()

#include "hardware/regs/vreg_and_chip_reset.h"
  // C:\Pico\PicoSDK_v1.5.0\pico-sdk\src\rp2040\hardware_regs\include\hardware\regs\vreg_and_chip_reset.h
#include "hardware/regs/watchdog.h"

const char reset_reason_txt[]  = 
"Reset Reason:\n"
" 0 unknown\n"
" 1 power-on or brown-out\n"
" 2 Hardware PIN Reset\n"
" 3 Software reset over WD\n"
" 4 Hardware watchdog timer reset\n";

uint8_t resetReason(bool talk) {
//-------------------- 
  io_rw_32 *reset_reason_reg = (io_rw_32 *) (VREG_AND_CHIP_RESET_BASE + VREG_AND_CHIP_RESET_CHIP_RESET_OFFSET);
  uint8_t nResReason = 0;
  
  uint8_t nWD_Reason = WD_Reason();  // SDK func watchdog_caused_reboot() does not deliver the reason
  
  if (nWD_Reason > 0){
    nResReason = nWD_Reason +  2;  // 3 and 4
  }else{   

    if ((*reset_reason_reg & VREG_AND_CHIP_RESET_CHIP_RESET_HAD_POR_BITS)) { 
      // POR: Last reset was from the power-on reset or brown-out detection
      nResReason = 1;
    }
    if ((*reset_reason_reg & VREG_AND_CHIP_RESET_CHIP_RESET_HAD_RUN_BITS)) { 
      // RUN: Last reset was from the RUN pin
      nResReason = 2;
    }  
  }
  if (talk){
    Serial1.printf("RESET Reason = %d\n", nResReason);
    Serial1.print(reset_reason_txt);
  }
  return nResReason;
}

uint8_t WD_Reason(void) {
//-----------------------
// Watchdog reason
  io_rw_32 *WD_reason_reg = (io_rw_32 *) (WATCHDOG_BASE + WATCHDOG_REASON_OFFSET);
  uint8_t nWD_Reason = 0;
  
  if ((*WD_reason_reg & WATCHDOG_REASON_FORCE_BITS)) { 
    // WATCHDOG_REASON_FORCE
    nWD_Reason = 1;
  } 
  if ((*WD_reason_reg & WATCHDOG_REASON_TIMER_BITS)) { 
    // WATCHDOG_REASON_TIMER
    nWD_Reason = 2;
  }
  return nWD_Reason;
}

output:

RESET Reason = 3
Reset Reason:
0 unknown
1 power-on or brown-out
2 Hardware PIN Reset
3 Software reset over WD
4 Hardware watchdog timer reset

[earlephilhower]

I think we need to drop the printouts, make that return an enum and not just a bare number, but it seems like a good idea for a PR! 👍

[kendo55]

Of course you are right.
I'm an old engineer who started to programing Microprocessors with the Intel 4040.
And it's now the last chance to come friendly with enums :-)

[palmerr23]

Kendo55,

Are you going to follow through with this addition?
I had a similar idea and will turn it into a pull request if you aren't going to. See also https://github.com/earlephilhower/arduino-pico/discussions/1843

Richard