vince.cimo
Well-known member
Hi guys. I have a custom Teensy LC implementation using your bootloader chips and am having issues getting the board to be detected via USB. Here's what I've got going on:
1. Probing the reset pin with my scope, I temporarily pull PTB2 on the MKL02 to ground.
2. I can see the MKL26 restarting and every once in a while will go high for a second, then sometimes go low and stay low until I re-plug in the USB.
3. So far every board (i've tried 5 boards), eventually works...the reset pin goes high, then stays high and the port shows up on the USB bus, but some of these boards are taking 20 minutes of fiddling around with the PTB2->MKL02 connection before I get a successful programming of the MKL26.
4. After this initial setup, the boards seem to reliably be able to be programmed via the usb connection.
Does this sound like I have noise on my PTA0 & PTA3 pins (clock and data pin connecting the MKL26 & MKL02)? Is there anything I can check out with a scope to confirm this?
I'm about to order a batch of 200 of these boards and it's going to be a real bummer if I have to sit for 20 minutes and fiddle with each one before I can get a reliable USB connection...
I'm attaching a screencap of my board layout.
1. Probing the reset pin with my scope, I temporarily pull PTB2 on the MKL02 to ground.
2. I can see the MKL26 restarting and every once in a while will go high for a second, then sometimes go low and stay low until I re-plug in the USB.
3. So far every board (i've tried 5 boards), eventually works...the reset pin goes high, then stays high and the port shows up on the USB bus, but some of these boards are taking 20 minutes of fiddling around with the PTB2->MKL02 connection before I get a successful programming of the MKL26.
4. After this initial setup, the boards seem to reliably be able to be programmed via the usb connection.
Does this sound like I have noise on my PTA0 & PTA3 pins (clock and data pin connecting the MKL26 & MKL02)? Is there anything I can check out with a scope to confirm this?
I'm about to order a batch of 200 of these boards and it's going to be a real bummer if I have to sit for 20 minutes and fiddle with each one before I can get a reliable USB connection...
I'm attaching a screencap of my board layout.