delay() not working ATMEGA328P-AU

[Georgew221]

Using MiniCore 3.0.2 locks the MCU when getting to int delay() processes. The processes that are sub-int (0.9) continue the MCU programming as expected. delayMicroseconds() seems to work okay, but not suitable for longer delay times.

delay(1); //Will break code/MCU pauses at the delay() indefinitely
delay(0.1); //MCU will continue the program

This is using a ATMEGA328P-AU and a 16MHz external crystal.

[MCUdude]

Can you post a bare minimum sketch that will reproduce your issue? Ideally a blink sketch of some sort.

delay(0.1); //MCU will continue the program

the delay number has to be an integer, so this won't/shouldn't work.

[Georgew221]

I've just bodged _delay_ms(1000); into working on it - I can use it as a workaround at the mo.

This is what I've got now;

#include <SoftwareSerial.h>
#include "util/delay.h" DELAY_BACKWARD_COMPATIBLE 

int ATReadyPin = A2;
const byte External_TX = 1;
const byte External_RX = 0;

//Serial Definitions
SoftwareSerial Ext_Comms(External_RX, External_TX);

void setup() {
  pinMode(ATReadyPin, OUTPUT);
  pinMode(External_TX, OUTPUT);
  pinMode(External_RX, INPUT);
  Ext_Comms.begin(19200);
  Ext_Comms.println("ATReady, enabling LIN controllers");
  digitalWrite(ATReadyPin, HIGH);
  _delay_ms(1000);
  digitalWrite(ATReadyPin, LOW);
}

void loop() {
  _delay_ms(1000);
  digitalWrite(ATReadyPin, HIGH);
  _delay_ms(1000);
  digitalWrite(ATReadyPin, LOW);
  Ext_Comms.println("Looped");
}

Changing any of the _delay_ms() to delay() will pause the MCU.

[MCUdude]

I'll give your code a try later today. Are you using a bootloader or an ISP programmer for uploading? And why would you use SoftwareSerial when hardware serial is available on the same pins?

[Georgew221]

Arduino as ISP as the programmer if that matters, although I have burnt the bootloader just to make sure the 328 isn't using the internal oscillator. I was trying to debug a baud issue so was using SoftwareSerial to quickly change the pins is all.

[MCUdude]

If you compile and upload using the default "Arduino UNO" option (not MiniCore), does it still freeze?

[Georgew221]

With bootloader burnt from Minicore, and compiling/uploading as if it were an Uno it still pauses at delay().

[Georgew221]

Just tried it on another PCB of mine and it works fine with Minicore. Possible a bad 328 but confused as to why the old _delay_ms() is working with Minicore on it but the normal one isn't? Assuming they a check the cycle counts in the same way as the timings of _delay_ms() are correct?

[MCUdude]

It probably is a bad chip. delay() and _delay_ms() are completely different. _delay_ms() is just a bunch of instructions (mostly NOPs I think) and your program will grow every time you call _delay_ms(). delay() and delayMicroseconds() on the other hand uses timer0 as their timekeeping. So if there is something related to timer0 that doesn't work in the chip, you might see the same results as we're getting. Where did you get your chips from?

[Georgew221]

They were assembled by JLCPCB so one would assume they're good. Marking as closed as most likely a fab issue 😊 Thanks for the quick reply!