Teensy 4.0 PC Connection Problems

M

Maklegend

New member
Hello everyone. This is my first question on this forum. I apologize in advance if this question has already been asked.
I created my own project based on the Teensy 4.0 schematic. I've checked the connections several times. Instead of using a micro USB connector, I used a USB-C connector. My problem is that when I connect the circuit to the PC, it's not recognized. Sometimes, however, it's recognized as an unknown device, and therefore I can't load my SKETCH.
The only thing I notice is that the LED connected to pin 11 of the bootloader flashes 9 times and sometimes 4 times.
Can anyone help me? I'd be grateful. Have a good evening everyone.
 
You can find the definitions for the blink codes <here> (scroll down to the "Troubleshooting & Diagnostic Blink Codes" section).

Hope that helps . . .

Mark J Culross
KD5RXT
 
kd5rxt-mark said:
You can find the definitions for the blink codes <here> (scroll down to the "Troubleshooting & Diagnostic Blink Codes" section).

Hope that helps . . .

Mark J Culross
KD5RXT
Click to expand...
Thanks Mark for the reply. I've actually already consulted that section, but unfortunately I haven't been able to resolve the problem. Using a DS213 oscilloscope, I noticed that I don't see the 24 MHz crystal oscillation, but I don't see it on an original Teensy 4.0 board either. I really don't understand what's causing the problem...
 
Hopefully this isn't thread hijack as I'm going through the same startup of a "own project based on the Teensy 4.x schematic".

I just finished spinning my own Teensy4.1 based board and am having similar issues and some fun getting it started up as well.

(Linux on my main machine...) If I plug the board in, nothing is noted as far as USB devices connecting, and no LED's blinking.
Pressing the reset button gets it started up, and (now that I've flashed blink onto it), blink works fantastically. I can reprogram, etc. Works great. But, it won't cold boot without pressing the reset button - a problem in my application unfortunately.
If I hold the reset button, I get two quick blinks every couple of seconds. If I hold until those double blinks, then release, it gets recognized (via dmesg) as:
New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 1-6.3.4: Product: SE Blank RT Family
usb 1-6.3.4: Manufacturer: NXP SemiConductors Inc
And then I get no red LED's doing anything. But, a quick press of the reset button gets it running the last code that I uploaded.
A long hold is no different than the shorter "hold" where I get the double blinks.

Any thoughts? Any help would be GREATLY appreciated. I have the schematics and layout in Altium CircuitMaker...
 
Maklegend,

I did some research last night - might be a startup issue with power supply rise time, reset hold time or decoupling caps. Yours does seem to indicate something with the JTAG side so there may be some things to check there. Did you copy the Teensy schematic verbatim, modify based on the 1062 manual, or something else? I'm hoping to dive deeper into mine this weekend - I'll report back what I find.

Andy
 
AndyMeyer said:
Maklegend,

I did some research last night - might be a startup issue with power supply rise time, reset hold time or decoupling caps. Yours does seem to indicate something with the JTAG side so there may be some things to check there. Did you copy the Teensy schematic verbatim, modify based on the 1062 manual, or something else? I'm hoping to dive deeper into mine this weekend - I'll report back what I find.

Andy
Click to expand...
Hi Andy, thanks for your interest.

Answering your question, I copied the Teensy's schematic. The only thing I changed is that I used a USB-C connector instead of the micro USB connector.
 
Maklegend,
Hmmm... I have a Teensy4.1 on my older version of this PCBA with wires running from the uUSB port to a USBC port and it works great. The next question then runs into layout or noise on your board, component selection, a manufacturing issue or something else.
Did you assemble your boards or have a PCBA house assemble for you? Mine were OshPark PCB's and I installed all of the components - maybe a dozen 0402's on the back side under the iMXRT1062. (and some whiskey to settle the hands. :) ) I did add some capacitance per the 1062 design manual - I'm trying to figure out if I added too much and caused myself another headache.
 
AndyMeyer said:
Maklegend,
Hmmm... I have a Teensy4.1 on my older version of this PCBA with wires running from the uUSB port to a USBC port and it works great. The next question then runs into layout or noise on your board, component selection, a manufacturing issue or something else.
Did you assemble your boards or have a PCBA house assemble for you? Mine were OshPark PCB's and I installed all of the components - maybe a dozen 0402's on the back side under the iMXRT1062. (and some whiskey to settle the hands. :) ) I did add some capacitance per the 1062 design manual - I'm trying to figure out if I added too much and caused myself another headache.
Click to expand...
Hi Andy, I initially tried soldering the components myself, but I had a hard time soldering the microprocessor. So I decided to have the board manufactured by a specialized company, so I'm pretty sure all the components are soldered correctly. I didn't add any additional capacitors; I just added the ones from the Teensy 4.0.
 
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