I've created a custom PCB using the ATMega328P. I'm running it on a CR2 battery (3V, 850mAh) with an 8MHz crystal (essentially a Pro Mini - something I've done many times before without any issues). I successfully uploaded the bootloader and managed to program the board fine.
However, on this design I have two load switches (TPS22860) which I'm controlling from pins D5 and D6. This is to switch power from the battery to a GPS module and a BME688 sensor.
The issue is, whenever I try to set either D5 or D6 HIGH, the ATMega will restart. In the code below which I put together to test it, it restarts at the end of the main loop.
int pwr = 5;
int pwrA = 6;
void setup()
{
Serial.begin(9600);
pinMode(pwr, OUTPUT);
pinMode(pwrA, OUTPUT);
Serial.println("SETUP FLAG");
}
void loop()
{
Serial.println("FLAG 1");
digitalWrite(pwr, HIGH);
digitalWrite(pwrA, HIGH);
Serial.println("FLAG 2");
delay(1000);
Serial.println("FLAG 3");
digitalWrite(pwr, LOW);
digitalWrite(pwrA, LOW);
Serial.println("FLAG 4");
delay(1000);
}
Serial monitor output below.
SETUP FLAG
FLAG 1
FLAG 2
FLAG 3
FLAG 4
�SETUP FLAG
FLAG 1
FLAG 2
FLAG 3
FLAG 4
�SETUP FLAG
FLAG 1
FLAG 2
FLAG 3
FLAG 4
I wasn't sure whether the ATMega was just restarting when it reached the end of the main loop , so I toggled D5 and D6 a few extra times within the main loop, but it still restarted after Flag 4.
Whenever I comment out the "digitalWrite(pwr, HIGH)" and "digitalWrite(pwrA, HIGH);", the ATMega stops restarting and it loops fine, even when I manually pull D5 and D6 HIGH.
The strange thing is, the device is fine when I run the more complex code below for the GPS module. It allows me to toggle D6 fine.
#include <TinyGPS++.h>
#include <SoftwareSerial.h>
#define rxGPS 3
#define txGPS 2
const int pwr = 6;
long lat, lon;
SoftwareSerial gpsSerial(rxGPS, txGPS);
TinyGPSPlus gps;
void setup()
{
Serial.begin(9600); // connect serial
gpsSerial.begin(9600); // connect gps sensor
pinMode(pwr, OUTPUT);
Serial.println("SETUP FLAG");
}
void loop()
{
digitalWrite(pwr, HIGH);
while (gpsSerial.available()) // check for gps data
{
if (gps.encode(gpsSerial.read())) // encode gps data
{
Serial.print("SATS: ");
Serial.println(gps.satellites.value());
Serial.print("LAT: ");
Serial.println(gps.location.lat(), 6);
Serial.print("LONG: ");
Serial.println(gps.location.lng(), 6);
Serial.print("ALT: ");
Serial.println(gps.altitude.meters());
Serial.print("SPEED: ");
Serial.println(gps.speed.mps());
Serial.print("Date: ");
Serial.print(gps.date.day()); Serial.print("/");
Serial.print(gps.date.month()); Serial.print("/");
Serial.println(gps.date.year());
Serial.print("Hour: ");
Serial.print(gps.time.hour()); Serial.print(":");
Serial.print(gps.time.minute()); Serial.print(":");
Serial.println(gps.time.second());
Serial.println("---------------------------");
//delay(4000);
}
}
Serial.println("Waiting for data...");
}
I've checked for shorts and the hardware seems fine - I've used this design many times before. The issue just seems to be the ATMega cannot assert those pins HIGH in certain cases without it restarting the device. I thought it may be some issue with the UART comms to the PC, but everything is fine with the GPS sketch. I then thought it may be some memory corruption? But I'm not sure how I'd investigate that further.
Any advice or suggestions would be appreciated!
