Hi,
We are currently trying out the EC200A-EU modem using the LTE OPEN EVB kit and stumbled on an error that we cannot understand or diagnose.
The firmware of the modem is EC200AEUHAR01A24M16
We set up a connection to an FTP server using AT+QFTPOPEN and try a 1MB file transfer using 'AT+QFTPPUT="out.bin","COM:",0
We have RTS/CTS enabled (IFC: 2,2). A transfer with a baudrate of 115200 works fine, as well as with 230400 or 460800. But when we try with 921600, the transfer starts for a while and then it seems that the board suddenly reset / restart. Power LED is still ON, but other LEDS shut off. And after a while we receive the RDY message on the AT interface.
We tried different settings and all lead to the same problem :
- different FTDI/RS232 cables
- different terminal (hterm on windows, cutecom on linux)
- using a python script directly with pyserial
- with a direct 3V UART using an external microcontroller.
- with different SIM card
- using 4G and 3G (sometimes transfers completed properly without reset using 3G only)
- with different power supply
We monitored the power:
- no drop of voltage is noticeable
- the current consumption seems fine, no sudden peak were observed, until the consumption drops and flatline
Maybe this is something known? Or perhaps you may have an idea of what could be the cause of the problem? Any guidance would be appreciated.
Best regards,
Guillaume