I have a board with various IO's connected to a Teensy 4.1. In addition I have a CR2032 battery connected to the VBAT pin.
The RTC works just fine.
All system functions are powered independent of the teensy. So for example I have a separate 3.3V regulator which provides power to the 3.3 peripherals (and is NOT connected to the teensy 3.3V rail). The 5V system rail powers the teensy on the VCC pin.
However, I have very strange behavior when applying system power after a power down.
With the system powered down, if I apply power via the USB (or 5V direct from an external power supply to VCC) then the Teensy will NOT restart. Power draw on the VCC pin is 0ma.
If I apply main board power, enabling my 3.3V and 5V system rails then the teensy will restart about 80% of the time. But sometimes not.
I suspect there is something on one of the pins causing the Teensy to not come out of SNVS mode (as described in application note: AN12245) with the hardware reset.
Does anyone know what Teensy 4.1 Pin I need to start looking at? I use about 80% of them.
The RTC works just fine.
All system functions are powered independent of the teensy. So for example I have a separate 3.3V regulator which provides power to the 3.3 peripherals (and is NOT connected to the teensy 3.3V rail). The 5V system rail powers the teensy on the VCC pin.
However, I have very strange behavior when applying system power after a power down.
With the system powered down, if I apply power via the USB (or 5V direct from an external power supply to VCC) then the Teensy will NOT restart. Power draw on the VCC pin is 0ma.
If I apply main board power, enabling my 3.3V and 5V system rails then the teensy will restart about 80% of the time. But sometimes not.
I suspect there is something on one of the pins causing the Teensy to not come out of SNVS mode (as described in application note: AN12245) with the hardware reset.
Does anyone know what Teensy 4.1 Pin I need to start looking at? I use about 80% of them.