SmartG100 GSM Module - Help

[haji_akhundov]

Hello everyone,

I have just received this component: SmartG100
http://www.mikroe.com/eng/products/view ... 100-board/

Unfortunately I am not able to find any good manuals on this product, the only one available on the website is this one:
http://www.mikroe.com/eng/downloads/get ... l_v100.pdf

I doesn't say much at all. I need a more detailed manual on this one. Does anyone know where I should look?
I need information such as the BAUD rate that the device is using for the UART communication etc.

Thanks in advance

[centu002]

Search for e "uBlox Leon-G100 GSM/GPRS module" on google.

[filip]

Hi,

As centu002 said, you should look this information in the "uBlox Leon-G100 GSM/GPRS module manual :
http://www.u-blox.com/en/wireless-modul ... amily.html

Regards.
Filip.

[haji_akhundov]

Thank you all,

I have looked at the different manuals you suggested.

This particular: http://www.u-blox.com/images/downloads/ ... 002%29.pdf has a lot about UART.

It has information such as:
1. autobauding is enabled by default (1200, 230400)
2. default frame recognition (8N1)
3. hardware flow control enabled by default etc.

I am still having problems with communicating with the board.
I am using 3 lines, Tx, Rx and GND. (the MAX232 voltage level shifter circuit works fine, when Tx and Rx are connected to each other I get echoes on my terminal).

Since only these signals are used, I assume I have to turn off the hardware flow control, so I am doing that with a

Code: Select all

at+ifc=0,0

It still does not work.

However nothing is working. I am not even seeing echoes from the board.

Any further suggestions?

Hope to hear from you soon

[filip]

Hi,

How did you connect the SmartG100 board to the PC ?
Or have you connected it to some development system ?

Regards,
Filip.

[haji_akhundov]

Filip,

Currently I am just trying to make it work from a PC. (I will be connecting it to a dev. board later on)

Well, I connected my PC's RS232 port to a RS232 to RS485 converter, from there to the GSM Module (Tx, Rx, Gnd)

In case you are wondering, the converter works fine, I have two converters, so I tested them from one PC to another and it is working fine. (PC <-> converter <-> converter <-> PC)

Regards

[filip]

Hi,

Well, I connected my PC's RS232 port to a RS232 to RS485 converter, from there to the GSM Module (Tx, Rx, Gnd)

Why did you use RS232 to RS485 converter ?
You should use something like this :
http://www.mikroe.com/eng/products/view ... 232-board/
Connect one end to the RS-232 and the other to the SmartG100 GSM Module.

Regards,
Filip.

[haji_akhundov]

Filip,

Isn't RS 485 a voltage specification of UART? I've used this converter several times before. My guessing right now is that the voltage levels are not correct somehow.

Do you know what are the UART voltage levels on this board? 3.3? 5?

Regards

[centu002]

Filip,

Isn't RS 485 a voltage specification of UART? I've used this converter several times before. My guessing right now is that the voltage levels are not correct somehow.

Do you know what are the UART voltage levels on this board? 3.3? 5?

Regards

I think is between 3.3V and 5V depending on transfer rate (for MAX3232)

Voltage levels
Diagrammatic oscilloscope trace of voltage levels for an uppercase ASCII "K" character (0x4b) with 1 start bit, 8 data bits, 1 stop bit.
The RS-232 standard defines the voltage levels that correspond to logical one and logical zero levels for the data transmission and the control signal lines. Valid signals are plus or minus 3 to 15 volts; the ±3 V range near zero volts is not a valid RS-232 level. The standard specifies a maximum open-circuit voltage of 25 volts: signal levels of ±5 V, ±10 V, ±12 V, and ±15 V are all commonly seen depending on the power supplies available within a device. RS-232 drivers and receivers must be able to withstand indefinite short circuit to ground or to any voltage level up to ±25 volts. The slew rate, or how fast the signal changes between levels, is also controlled.
For data transmission lines (TxD, RxD and their secondary channel equivalents) logic one is defined as a negative voltage, the signal condition is called marking, and has the functional significance. Logic zero is positive and the signal condition is termed spacing. Control signals are logically inverted with respect to what one sees on the data transmission lines. When one of these signals is active, the voltage on the line will be between +3 to +15 volts. The inactive state for these signals is the opposite voltage condition, between −3 and −15 volts. Examples of control lines include request to send (RTS), clear to send (CTS), data terminal ready (DTR), and data set ready (DSR).
Because the voltage levels are higher than logic levels typically used by integrated circuits, special intervening driver circuits are required to translate logic levels. These also protect the device's internal circuitry from short circuits or transients that may appear on the RS-232 interface, and provide sufficient current to comply with the slew rate requirements for data transmission.
Because both ends of the RS-232 circuit depend on the ground pin being zero volts, problems will occur when connecting machinery and computers where the voltage between the ground pin on one end, and the ground pin on the other is not zero. This may also cause a hazardous ground loop. Use of a common ground limits RS-232 to applications with relatively short cables. If the two devices are far enough apart or on separate power systems, the local ground connections at either end of the cable will have differing voltages; this difference will reduce the noise margin of the signals. Balanced, differential, serial connections such as USB, RS-422 and RS-485 can tolerate larger ground voltage differences because of the differential signaling.[6]
Unused interface signals terminated to ground will have an undefined logic state. Where it is necessary to permanently set a control signal to a defined state, it must be connected to a voltage source that asserts the logic 1 or logic 0 level. Some devices provide test voltages on their interface connectors for this purpose.

[filip]

Hi,

Do you know what are the UART voltage levels on this board? 3.3? 5?

This board can work with both 3.3V and 5V MCUs, and on the other side (where the DB9 connector is ) there are standard RS-232 voltage levels.

Regards,
Filip.

[haji_akhundov]

Hello,

I decided to use the USB to UART converter for now: http://www.mikroe.com/eng/products/view ... art-board/

Everything is working so far,

Regards

[tritech]

Hi

I am using SmartG100 GSM modem and I need to send/receive messages via AT Commands. I connected it to MAX3232 board and gave it as RS232 to PC COM port. Following are the connections used:
PIN6 of SmartG100 -> TX of MAX3232
PIN7 of SmartG100 -> RX of MAX3232
Vcc of SmartG100 -> Vcc of MAX3232
GND of SmartG100 -> GND of MAX3232

DB9 wiring:
RX of MAX -> TX of PC COM
TX of MAX -> RX of PC COM
GND of MAX -> GND of PC COM

I am not getting any responses. Is there any connections which I missed out or wrong?
Pls provide suggestions. Thanks

[haji_akhundov]

Hi

I am using SmartG100 GSM modem and I need to send/receive messages via AT Commands. I connected it to MAX3232 board and gave it as RS232 to PC COM port. Following are the connections used:
PIN6 of SmartG100 -> TX of MAX3232
PIN7 of SmartG100 -> RX of MAX3232
Vcc of SmartG100 -> Vcc of MAX3232
GND of SmartG100 -> GND of MAX3232

DB9 wiring:
RX of MAX -> TX of PC COM
TX of MAX -> RX of PC COM
GND of MAX -> GND of PC COM

I am not getting any responses. Is there any connections which I missed out or wrong?
Pls provide suggestions. Thanks

tritech,

Make sure the DIP switches (SW1) are correctly configured. Use http://www.mikroe.com/downloads/get/111 ... l_v100.pdf (SmartG100 connection schematics) for reference.

Hope that helps.

Haji

[tritech]

Hi

DIP 1.1 and 1.5 are ON. I have sent a picture of the connections. Pls check it. Thanks.