Raspberry Pi restarts when Notecard modem is on.
Use Raspberry Pi 4 or provide supplemental power to the Notecarrier-Pi Hat.
Raspberry Pi Restarting
When I issue a command to the Notecard, the Raspberry Pi restarts, and also causes the Notecard to restart.
- Raspberry Pi 3B+
- Notecard (any variant)
Raspberry Pi / Notecard Connection Configurations:
- Notecard mounted to a Notecarrier-Pi Hat that is mounted to the Raspberry Pi headers
- Notecard mounted in any Notecarrier, connected to the Raspberry Pi via USB port
Approximate Reproduction Steps:
- Ensure the Notecard modem is on.
This can be done by enabling hub continuous connection mode on the Notecard
This forces the modem to be on continuously.
The Notecard modem is on if the GREEN LED on the Notecard is on
More about Notecard LED
- Issue some additional command to Raspberry Pi peripheral that causes additional current draw
We have seen this when opening the I2C port or serial port on the Raspberry Pi to the Notecard.
Precise reproduction steps are difficult to determine. The issue is the total current drawn by the Raspberry Pi, Notecard, and any other devices that might be connected to the Raspberry Pi and drawing current.
1. Apply supplemental power to Notecard over USB
If hardware configuration is using the Notecarrier-Pi Hat mounted to the Raspberry Pi header, then plug in a USB power supply to the Notecarrier-Pi Hat micro USB port.
In this configuration, the micro USB port on the Notecarrier-Pi Hat only supplies additional power to the Notecard. A diode network prevents the sharing of power with the Raspberry Pi or other Pi-hats.
2. Use a Raspberry Pi 4
The Raspberry Pi 3B+ has a current limiting resettable fuse on the 5 volt supply trace. The modem on the Notecard is connected to this trace via the Raspberry Pi header.
If the total current draw on this power supply from the Notecard, Raspberry Pi operation, and other power consuming peripherals exceeds much more than 2.5 amps, then the fuse trips, and causes power to be cut to the Raspberry Pi and child components.
The Raspberry Pi 4 board no longer contains that fuse on the 5 voltage supply trace.
Early versions of the Raspberry Pi 4 hardware seemed to have some other issues. Double check you are using a relatively recent hardware version.
To get hardware version information, use the following on the Raspberry Pi terminal:
sudo /opt/vc/bin/vcgencmd version
Sep 2, 2020
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