Hi.
After only reading for all times, I registered today to ask a question about the Teensy 4.1.
This one Teensy 4.1 is dedicated to testing highly efficient Organic LEDs. The Teensy is powered by USB.
At higher temperature it works totally normal, as expected, and draws about 250mA.
During a low temperature test, the Teensy 4.1 started to show a strange behavior.
If the setup was left at 9°C air 45% RH for minimum 4 hours, the Teensy will not boot any more with the following code:
The low signals will never appear on the pins, instead they show a pulldown behaviour, and the Teensy 4.1 draws about 2A from the USB in random short pulses, but nothing on the teensy board heats up.
After power cycling, the cool Teensy red LED sometimes blinks series of two, or stays completely dark, or stays dimly lit with obvious darker flickering.
Once this strange behavior happened, the Teensy will never boot the code again, even after warming it up to room temperature.
Holding the Program Button on the cool Teensy while power cycling and keeping it pressed for about 30 seconds, does sometimes lead to a short red blip followed by very long >60s bright red, but the orange blink does not come up, even after power cycle. If the setup is rewarmed again, this restore procedure does work normally as expected.
If I change the FLASHMEM to FASTRUN, it boots and works normally, even in the cooled condition.
I've also tried longer startup delay, but even two seconds do not give any different result.
What could this be?
The Teensy 4.1 is one of the first series.
Would a new Teensy 4.1 from the most recent production run solve the issue?
After only reading for all times, I registered today to ask a question about the Teensy 4.1.
This one Teensy 4.1 is dedicated to testing highly efficient Organic LEDs. The Teensy is powered by USB.
At higher temperature it works totally normal, as expected, and draws about 250mA.
During a low temperature test, the Teensy 4.1 started to show a strange behavior.
If the setup was left at 9°C air 45% RH for minimum 4 hours, the Teensy will not boot any more with the following code:
Code:
[...]
FLASHMEM
void setup() {
// waiting, give everything time to start up
delay (500);
// all LEDs on
for (b = 0; b < sizeof(LEDpin); b++) {
pinMode(LEDpin[b], OUTPUT_OPENDRAIN);
digitalWrite(LEDpin[b], 0);
}
[...]
After power cycling, the cool Teensy red LED sometimes blinks series of two, or stays completely dark, or stays dimly lit with obvious darker flickering.
Once this strange behavior happened, the Teensy will never boot the code again, even after warming it up to room temperature.
Holding the Program Button on the cool Teensy while power cycling and keeping it pressed for about 30 seconds, does sometimes lead to a short red blip followed by very long >60s bright red, but the orange blink does not come up, even after power cycle. If the setup is rewarmed again, this restore procedure does work normally as expected.
If I change the FLASHMEM to FASTRUN, it boots and works normally, even in the cooled condition.
Code:
[...]
FASTRUN
void setup() {
// waiting, give everything time to start up
delay (500);
// all LEDs on
for (b = 0; b < sizeof(LEDpin); b++) {
pinMode(LEDpin[b], OUTPUT_OPENDRAIN);
digitalWrite(LEDpin[b], 0);
}
[...]
What could this be?
The Teensy 4.1 is one of the first series.
Would a new Teensy 4.1 from the most recent production run solve the issue?