Weird Custom Teensy 3.2 Behavior

[majorjoel2]

I am on a competitive robotics team and we are using a Teensy as a co-processor. I designed a custom teensy split between two boards. On the main board I have most of the components and on the secondary board I have C7 (VUSB Capacitor), F1 (VUSB Fuse), The VUSB Pad as a switch, S1 (Program Button), R1 & R2 (Current Limiting resistors on the USB0), and U2 (The bootloader/programmer IC). This isolates the programmer from the U1 (Cortex M4). The boards are connected by a 2x5 pin header. The 10 pins are 5V, 3.3V, GND, and U1 5,6,22,23,24,25, and 34. I uploaded blink and the main board blinks the led while the programmer is connected and then when I turn it off and disconnect the programmer and power the main board it blinks. This is the expected. I then loaded on the actual code and it worked. After a while it stopped working. The main board now only starts the program if the programmer is connected but if you disconnect the programmer while the board is powered it keeps running the code. Does the programmer send anything on power up or is it a floating input error. If it is a floating input error would a pull up, pull down, or grounding the pins work?

I have attached pictures of the uploader and main board schematic. They match up with the teensy 3.2 schematic.

 

[blackketter]

I can't see from the schematic what is connected to the reset pin (pin 10 on your connector). I wonder if you'd need a pull-up resistor on that pin.

 

[majorjoel2]

Thank you for the suggestion. I connected a 10k pull up to 3.3 volts but it didn't fix the issue.