I'm having trouble getting my Raspberry Pi to communicate with a SIM7600X 4G HAT using Minicom. I can't seem to input any AT commands into Minicom or any other terminal emulator.
Here's a summary of the situation, hardware setup, and the steps I've taken so far:
Hardware Setup:
- Raspberry Pi model: 4B
- SIM7600X 4G HAT seated on the GPIO pins
- Using the USB port on the HAT (not the UART bridge)
- Power supply: 6.5A power charger
Initial Problem:
- Minicom does not accept any keyboard input when opened.
- Tried connecting with both symlink /dev/sim7600x_usb and direct /dev/ttyUSB* paths.
Steps Taken:
Checked Hardware Connections:
- Ensured the HAT is properly seated and USB cable is secure.
- Tried different USB cables and ports.
Confirmed Power Requirements:
- Verified that the power supply is adequate (2.5A or greater).
Reviewed Jumper and Switch Settings:
- Checked the DIP switch and jumper settings based on the Waveshare guide showing 3v3 and PWR as jumper shorted
- UART Jumper set to short A&B on both left and right pins
LED Status Jumper and Switch Settings:
- Solid Red PWR
- Flashing Red NET
Ensured Correct Drivers:
- Confirmed that usbserial and option drivers are loaded.
Disabled Serial Console Over GPIO:
- Used raspi-config to disable serial console and enable serial hardware.
Verified Modem Detection:
- The dmesg command shows the modem cycling through ttyUSB devices (indicating possible power issues or mode switching).
Attempted Direct Connection without Symlink:
- Tried accessing the modem using /dev/ttyUSBx directly in Minicom.
Ran Minicom with Superuser Permissions:
- Used sudo minicom -D /dev/ttyUSBx.
Tested Minicom Without Configuration File:
- Executed sudo minicom --noinit -D /dev/ttyUSBx.
Checked for Conflicting Processes:
- Ensured no other process is using the modem with lsof | grep ttyUSBx.
Rebooted Raspberry Pi:
- After making configuration changes, rebooted to ensure changes took effect.
Current State:
/dev/sim7600x_usb points to bus/usb/001/088 instead of a /dev/ttyUSB* device.
DIP switches on the HAT are set according to the manual, but I can't confirm this is correct.
When connected via USB, dmesg shows the device repeatedly connecting and disconnecting from ttyUSB ports.
I'm unsure if this issue is caused by power instability, incorrect mode settings on the HAT, or a problem with the drivers or Raspberry Pi configuration.
Any insights or suggestions on how to resolve this issue would be greatly appreciated.
Thank you!