Frequently caused by a blown backlight diode or a damaged FPC connector on the mainboard itself.
E7A MB PCB V3 Wiring Diagram - Printed Circuit Board - Scribd
| Symptom | Likely Cause | Solution | |---------|--------------|----------| | No device found | GND missing or broken trace | Check continuity between debugger GND and board GND | | Target voltage too low (0V) | VREF not connected to board’s 3.3V rail | Solder a jumper from a 3.3V test point to pin 1 of the link | | SWD protocol error | Clock speed too high | Reduce SWCLK to 1 MHz or lower | | Reset failed | nRESET line held low by onboard supervisor | Temporarily disconnect nRESET; use software reset instead |
Frequently caused by a blown backlight diode or a damaged FPC connector on the mainboard itself.
E7A MB PCB V3 Wiring Diagram - Printed Circuit Board - Scribd e7a mb pcb v3 link
| Symptom | Likely Cause | Solution | |---------|--------------|----------| | No device found | GND missing or broken trace | Check continuity between debugger GND and board GND | | Target voltage too low (0V) | VREF not connected to board’s 3.3V rail | Solder a jumper from a 3.3V test point to pin 1 of the link | | SWD protocol error | Clock speed too high | Reduce SWCLK to 1 MHz or lower | | Reset failed | nRESET line held low by onboard supervisor | Temporarily disconnect nRESET; use software reset instead | Frequently caused by a blown backlight diode or
