Hi, I recently posted another question regarding a shift register signal not holding - the shift register would activate a MOSFET which would run a motor, which would work but only for a few seconds.
To fix this, I used the following code
int c = 0;
while(c < 1)
{
digitalWrite(2,LOW);
SPI.transfer(128);
SPI.transfer(0);
digitalWrite(2,HIGH);
}
Which works. But, I'm worried about whether having the shift register constantly activated will wear the shift register out. Do you know if it has a maximum number a cycles, and in your opinion, would this code run through the lifetime of the register rather quickly?
As long as the device absolute maximum limits are not violated it should last a very long time...
I wouldn't worry about wearing it out.. I would however reaad the data sheet and verify that your power supply and I/O circuitry don't violate the Absolute Maximum parameters listed on the data sheet..
I've been using my computer for 3 years and it does a few billion operations a second and has not worn out yet. Your shift register, as logic circuit, will work just as well.
For reference, very few ICs "wear out" no matter how much you use them. Some exceptions including programming flash or EEPROMs, but that is really the exception rather than the rule.
schrodingers_hat:
I looked at the spec sheet to no avail.
Not a surprise. Just like the also-missing "mean time between gamma ray bursts" section, it is missing because it does not apply. The number of sections left out of the data sheet for this very reason is astronomical.
Shiftregisters use flipflops, transistors, there's nothing to wear out ..
The capacitor is the first to fail, refresh writes in memory, the voltage gets unstable and leads to a bad read, but transistors hardly fail unless exposed to too much current or voltage.