We have just received a few BG770A-GL TE-A modules. With our existing UMTS/LTE-EVB-KIT, we are unable to send any characters to the module via UART (MAIN). When we turn on the module, we do see TX data:
RDY
+CFUN: 1
+CPIN: NOT INSERTED
APP RDY
However, we cannot type any AT commands at this point, as if the RX signal is not hooked up. We can replace the BG770A module with a BG96/95, and that works perfectly fine to send commands, so I have verified the USB/Serial cable is OK.
Is there something special on this module that needs to be set? Have tried different flow control settings, and state of the PON_TRIG switch on the BG770A TE-A
I have been able to talk via MAIN UART, but only after attaching UART_DBG, as you mentioned.
I am confused on this behavior. Why does the UART_DBG need to be attached in order for us to use primary AT commands on the MAIN UART? What does this mean for production?
For BG77xA-GL or BG95xA-GL series module, the comminication of MAIN UART controled by PON_TRIG pin, only in High posistion AT commands can be sent, and PON_TRIG need
supply by USB cable( PON_TRIG needs to be pulled high electricity level externally). this is mandatory.
Hi
i have the same issue with BG77
the MAIN UART have no response
what could be the problem
is this the same problem as MG77xA-GL and need to pull high the PON_TRIG?
custom
the board is connected to the network and it’s working.
UART has been connected to usb to ttl 5v module directly but no response form the module after sending AT commands and when i reset the board it sends some none sense characters except that i get nothing from the module
i guess that it’s because of the voltage level difference but i had another EC200 module that was working with the same design.
I have encountered similiar issue with MAIN UART reception. In our design we have PON_TRIG pin pulled high to 1.8V from external MCU. Power up sequence is the same as described in “hardware design” note. Still, modem in not responding for any AT commands, although I can see initial messages like:
RDY
+CFUN: 1
APP READY