DumpsterDoofus
Member
Hello, I'm connecting my Teensy 4.1 via its header pins to a "daughterboard" with the below schematic and PCB:
The external DC power supply jack (U1) and ribbon cable connectors (U2, U3) are not connected to anything and thus are floating. So the only connected Teensy pins are the 3 GND pins, and pin 35 (which on the PCB is marked as J2 pin 22, connected to R2).
Regardless of what program I upload to the Teensy, it only runs for about 1 second before the red flashing LED blinks 7 times, which according to the Troubleshooting & Diagnostic Blink Codes is a "ARM JTAG DAP Communication Error".
I think I've ruled out software as the culprit, as I still reproduce the error with the below simple program, which flashes the orange LED at 5 Hz:
When the Teensy is not connected to the daughterboard, the orange LED flashes continuously.
When the Teensy is connected to the daughterboard, the orange LED flashes about 2-8 times before stopping, and then a few seconds later the red error LED flashes 7 times.
The same 7 red flash error also occurs when the DC jack is plugged into a 3.3V DC power supply, and also when the U2/U3 connectors are connected to a pair of other boards (whose schematics I can provide, although it's not clear they'd help because the error occurs even when they're not connected).
Any idea what is wrong with the schematic? My intent was to read pin 35 to detect when the external 3.3V power is connected. But even with the minimal program above that doesn't read pin 35, the Teensy goes into a fault state.
EDIT: Oof, it looks like I swapped the PCB position for J1 and J2? J2 should be on top, and J1 on bottom?
The external DC power supply jack (U1) and ribbon cable connectors (U2, U3) are not connected to anything and thus are floating. So the only connected Teensy pins are the 3 GND pins, and pin 35 (which on the PCB is marked as J2 pin 22, connected to R2).
Regardless of what program I upload to the Teensy, it only runs for about 1 second before the red flashing LED blinks 7 times, which according to the Troubleshooting & Diagnostic Blink Codes is a "ARM JTAG DAP Communication Error".
I think I've ruled out software as the culprit, as I still reproduce the error with the below simple program, which flashes the orange LED at 5 Hz:
C++:
#include <Arduino.h>
void setup()
{
pinMode(LED_BUILTIN, OUTPUT);
}
void loop()
{
digitalWrite(LED_BUILTIN, HIGH);
delay(100);
digitalWrite(LED_BUILTIN, LOW);
delay(100);
}When the Teensy is not connected to the daughterboard, the orange LED flashes continuously.
When the Teensy is connected to the daughterboard, the orange LED flashes about 2-8 times before stopping, and then a few seconds later the red error LED flashes 7 times.
The same 7 red flash error also occurs when the DC jack is plugged into a 3.3V DC power supply, and also when the U2/U3 connectors are connected to a pair of other boards (whose schematics I can provide, although it's not clear they'd help because the error occurs even when they're not connected).
Any idea what is wrong with the schematic? My intent was to read pin 35 to detect when the external 3.3V power is connected. But even with the minimal program above that doesn't read pin 35, the Teensy goes into a fault state.
EDIT: Oof, it looks like I swapped the PCB position for J1 and J2? J2 should be on top, and J1 on bottom?
Last edited: