The MCU:
I bought a few T4.1’s (https://www.sparkfun.com/products/20360) from Sparkfun a few days ago, here’s what went wrong . . .
This is (probably ) not a code issue.
I have a simple circuit running two 3.3v SPI displays to run gif frame animations.
The Wiring:
The PC carrier board that I built for this is really just a connector to attach the cable harnesses from the MCU to the displays.
It is essentially the same configuration as I pre-tested on a solderless breadboard, except for the diode, since it needs to run without USB.
The only component on the board other than wire, the IC socket, and a terminal screw-down is the single 4001 diode inline between the V-in main and the wire to the power supply. I did check the board for shorts, and I never soldered anything with the Teensy in place in its socket.
The PC board is a simple half size breadboard footprint by Electro-cookie if it matters.
Connection to the displays is using Male to Female Breadboard Jumper Wires, with the females glued together as a connector and the male pins soldered to the board, thus making the displays detachable.
The Display:
https://www.amazon.com/gp/product/B0711 … UTF8&psc=1
Pretty sure that’s this: http://www.hiletgo.com/ProductDetail/2169547.html
There seems to be no datasheet for this board, but there is one for the 1331 controller running the OLED.
According to the 1331 controller datasheet, the common maximum sink current for the 1331 unit is 60mA. The site that makes the display, Hiletgo, has no current info for the overall 96x64 OLED display. I have 2 of these in use. I believe Teensy 4.1 can put out 250mA from its 3.3 volt dc output maximum.
The Power:
I was running the board from a wall-wart 500mA 5V unit, well within the Teensy’s power demands, I believe.
I had the circuit running for a while this way, from the wall-wart, including disconnecting/reconnecting power.
Previously, I was running the circuit for hours using the USB out on my laptop. Both displays lit up fine and no over heating.
The animation sketch works. The displays both pull from the 3.3 v DC on the board. The Teensy V-in, protected with a diode is 5V DC.
I’ve also tested the set-up with the Sumotoy “Bubbles” example from the 13XX library on github.
https://github.com/sumotoy/SSD_13XX/com … 93f078af48
The Problem:
The problem is the Teensy just flatlined! The chip near the 3V regulator got really hot, and the system shut down. As noted above, I’ve checked both before installing the chip and then after the failure with the chip removed, but there are no shorts in my PC board or connectors that I can find.
One forum I looked at said to check to see if the 3.3v shows a short to GND. It does. Any ideas on what I did wrong and how to prevent it?
I was so upset that I built a new replacement PC connector board since I had all the parts using absolutely nothing from the previous board. I moved a few wires around to reduce any possible stress and improve access to the Teensy.
Hooked up to my USB now, I programmed in the Bubbles sketch, and it ran, then, before I was even able to call up the animation sketch, let alone upload, disaster struck AGAIN! Ughhhhh. Same exact issue, with a new PC connector board and a new Teensy.
Now 2 Teensy’s not functioning.
I am at a loss.
Please help.