Hi guys I am running this code on an Attiny85 but it keeps failing after a week or so. Sometimes it can be re-programmed but sometimes it fails altogether and requires replacement.
This is the code which works perfectly:
`Use code tags to format code for the forum`// Attiny85 program for power reduction of electromagnetic motor brakes.
// See http://tvdr.de/sim/3/brakes.htm.
// Provided as is, without any warranty. Free as in beer.
// Author: Klaus.Schmidinger@tvdr.de.
// I/O pins:
#define pCtl PB0 // connects to the control line of the M4S controller
#define pLed PB1 // controls the onboard LED (on if M4S control is low)
#define pPwr PB2 // connects to IN1+IN2 of the relais board
#define pXcg PB4 // connects to IN3+IN4 of the relais board
// Timing:
#define ReleaseTime 1000 // ms
// Globals:
bool BrakesReleased = false;
bool PowerReduced = false;
unsigned long ReleaseStart = 0;
void RelaseBrakes(void)
{
digitalWrite(pPwr, LOW);
digitalWrite(pXcg, LOW);
BrakesReleased = true;
PowerReduced = false;
}
void EngageBrakes(void)
{
digitalWrite(pPwr, HIGH);
digitalWrite(pXcg, HIGH);
BrakesReleased = false;
}
void ReducePower(void)
{
digitalWrite(pXcg, HIGH);
PowerReduced = true;
}
void setup()
{
// I/O pins:
pinMode(pCtl, INPUT_PULLUP);
pinMode(pLed, OUTPUT);
pinMode(pPwr, OUTPUT);
pinMode(pXcg, OUTPUT);
digitalWrite(pLed, LOW);
digitalWrite(pPwr, HIGH);
digitalWrite(pXcg, HIGH);
}
void loop()
{
if (digitalRead(pCtl) == HIGH) {
digitalWrite(pLed, LOW);
EngageBrakes();
}
else if (!BrakesReleased) {
digitalWrite(pLed, HIGH);
RelaseBrakes();
ReleaseStart = millis();
}
else if (!PowerReduced) {
if (millis() - ReleaseStart > ReleaseTime) {
ReducePower();
}
}
}
Any idea why it keeps failing?
Please correct your post and add code tags around your code.
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Tell us about your circuit, power etc.. The code you shared is straightforward and would not damage the chip by itself. The issue is almost certainly electrical or hardware-related.
➜ relay board does not have proper flyback diodes ?
➜ weak regulator, insufficient decoupling, or long wires with power supply to the ATtiny85 which dips or spikes when the relay engages ?
➜ relay module inputs expecting a heavy sink/source current (some boards need >20 mA on each input), overstressing the MCU's pins ?
...
below your existing posts.
