Smart G100 Board and USB UART Board to PC connection

[algood]

Hi,

I wanted to connect Smart G100 board to computer using USB UART Board. I connected as follows:

Smart G100 Board | USB UART Board
Pin 7 ---> Tx pin
Pin 6 ---> Rx pin
Gnd ---> Gnd
vcc ---> vcc

I used MikroElektronika Usart Terminal application to connect to the modem by selecting the correct com port and the following settings:
baud rate: 19200
Stop Bits: One Stop Bit
Parity: None
Data bits: 8
Buffer: 1024
Flow Control: None


After making the connection I issued the AT command but no reply from the modem. I could not get the PC to communicate with the modem.

I tested the Smart G100 board with the example program and it works.
I also crossed the pin connections between the modem board and the USB UART Board i.e:
Pin 7 ---> Rx pin
Pin 6 ---> Tx pin

but nothing was happening.

Is there anything I missed?

Can you help please?

[janko.kaljevic]

Hello,

If the board works fine with controller, then most probably there is some problem with connections.
Please can you tell me how did you connect PC to Smart G100 board?

It is important how you connected Vcc pin on the 2x5 connector on the board.
Here you should connect same voltage as you use on your board with MAX or FTDI chip.

Best regards.

[algood]

Hello,

Thank you for your reply.

I connected the PC to the Smart G100 board using the USB UART Board. The connections are as described in my first post. The voltage is set to 5v in both boards.

I also tried changing the voltage jumper to 3.3v in both boards but nothing happened.
I also tried the USB UART 2 Board but same result, no communication between the PC and the modem..

I must admit, initially I couldn't figure out which pin is the Vcc because I was using the EasyPROTO Board. After a closer look at the connections I figured out which pin is which. I hope what I did didn't damage the modem and/or the USB UART Board.

Regards;;

[janko.kaljevic]

Hello,

Please note that you have to connect 5V on Vcc pin on the 2x5 connector on the SmartG100 board. also you will have to bring 5V at the Vcc pin on USB UART board.
So it is not enough to just connect Vcc pin from USB UART to Vcc pin on the SmartG100 board.

Also note that there is a start taster on SmartG100 board.
After powering it up, you will need to press and hold this button for two seconds and then release it.
Now you should be able to communicate with modem properly.

Best regards.

[algood]

Hello,

Thank you for the clarification.

I do supply the Smart G100 Board with external power supply (12v) and press the TACT switch for 2 seconds to power ON the modem.

I understand from your reply that I am missing the 5v supply for both the Smart G100 board and the USB UART Board, am I right?
I thought we get the 5v supply from the USB port from the PC through the USB UART Board. Isn't it enough or do I have to provide another 5v supply? If I do, will it clash with the USB 5v supply from the PC?

Regards;;

[janko.kaljevic]

Hello,

Please check schematics of the SmartG100 Board.
You will see that voltage on Vcc pin is important because it generates voltage level for out put signal.

It is best to use stable 5V for this pin.

Best regards.