I have the following scenario
T4 with coin cell for RTC connected to PC-USB. (T4 is soldered to revD audioboard, no external power)
SW shuts down Teensy (turns off power). (SNVS_LPCR |=(1<<6) ; ) (T4 will be woken-up later by RTC alarm)
At this point T4 cannot be reprogrammed anymore
no reaction to
- button-press
- hold botton while disconnect and reconnect PC-USB
To reprogram T4, I need to disconnect coin cell
and hold botton while disconnect and reconnect PC-USB (red light shows bootloader activity)
wakeup-of T4 by connecting shortly reset-pin to ground, works.
It seems existing external VBAT interferes with boot-process
not sure if this is a 'feature' of my program (SNVS setting) or of the boot process.
T4 with coin cell for RTC connected to PC-USB. (T4 is soldered to revD audioboard, no external power)
SW shuts down Teensy (turns off power). (SNVS_LPCR |=(1<<6) ; ) (T4 will be woken-up later by RTC alarm)
At this point T4 cannot be reprogrammed anymore
no reaction to
- button-press
- hold botton while disconnect and reconnect PC-USB
To reprogram T4, I need to disconnect coin cell
and hold botton while disconnect and reconnect PC-USB (red light shows bootloader activity)
wakeup-of T4 by connecting shortly reset-pin to ground, works.
It seems existing external VBAT interferes with boot-process
not sure if this is a 'feature' of my program (SNVS setting) or of the boot process.