Arduino GPRS+GSM SIM300 Module+Development Board Ver2 Interfacing

Hi,

I bought a Arduino GPRS+GSM SIM300 Module+Development Board Ver2 module. but I could not interface it with my PC. If i want to communicate with the module while directly connected to my PC via RS232, how do i bridge the P3 pins? I've been trying AT commands and i get no reply from the module. I don't receive an OK whet i type AT, the baud rate is set. This is bit urgent. If you can give me a suggestion it will be the grear help for me. Thanks a lot.

You need to upload Circuit diagram here

**broken link removed**

Thank you for replying. this is the link of the product. it has sim300 manual and schematic. still didn't access this module using PC

Don't know why the link is not working right now, may be some server issue, try to upload schematic diagram here.

Or do this.

I think in your dev board their must a MAX232 or similar IC, and there were few jumpers should be there, Download Max232 datasheet and see TTL Rx and Tx pins, via jumpers you should connect SIM300 Rx pin to Max232 Tx TTL pin and Sim300 Tx pin to Max232 Rx TTL pin. before powering up the circuit make a continuty test with a continuty tester/meter to ensure that you had set jumpers correctly as i said. After ensuring power up your board and check voltages on SIM300 module, VBAT pins of Module must have in between 3.5 to 4.2 volts.

After voltage checking open hyper terminal and Set baudrate to 9600 with 8 bit no parity and connect it. SIM300 modules are factory set for Auto baudrate, if found no response from SIM300 than try other baudrate. and enable Echo command for hyperterminal by using 'ATE1' command. You will get all command and characters that you are sending to SIM300.

For microcontroller you must disable Echo by 'ATE0' command

Hope thsi will work for you

Thank you for replying. I have attached the schematic pdf of the module. I will check the VBAT pin voltages. Thank you

sahancr said:

Thank you for replying. I have attached the schematic pdf of the module. I will check the VBAT pin voltages. Thank you

Click to expand...

Set the Jumper P3 as shown in Figure uploaded

Dear masterleous,

Thank you for quick reply. jumpers are same as you told. I have connected 1-3 and 6-8 together.

as your first instruction i did the following procedure.

first i checked the max232 connections. it was right. then check the VBAT voltages. it is near to 4V.

yesterday system LED turned on 3 seconds. turn off few milliseconds. at the same time Net LED turned on.
Then net LED turned off and system LED turned on for 3 seconds.

today net LED doesn't working. But system LED blinks rapidly.

After that I went to Control Panel -> Phone and Modem Options and tried to configure the module. screen shots of every step is attached. log file gives the error. also query modem function is disabled.

after configuring the module open the hyper terminal and configure baud rates.
Sim300 Manual tells after connecting the module to hyper terminal it displays the "RDY".
but it didn't.
then I typed "AT". but didn't get a reply.

then typed a "ATE1" command. after some time hyper terminal displays unidentified characters. Screen shot is attached. but it happened once

sahancr said:

Dear masterleous,

Thank you for quick reply. jumpers are same as you told. I have connected 1-3 and 6-8 together.

as your first instruction i did the following procedure.

first i checked the max232 connections. it was right. then check the VBAT voltages. it is near to 4V.

yesterday system LED turned on 3 seconds. turn off few milliseconds. at the same time Net LED turned on.
Then net LED turned off and system LED turned on for 3 seconds.

today net LED doesn't working. But system LED blinks rapidly.

After that I went to Control Panel -> Phone and Modem Options and tried to configure the module. screen shots of every step is attached. log file gives the error. also query modem function is disabled.

after configuring the module open the hyper terminal and configure baud rates.
Sim300 Manual tells after connecting the module to hyper terminal it displays the "RDY".
but it didn't.
then I typed "AT". but didn't get a reply.

then typed a "ATE1" command. after some time hyper terminal displays unidentified characters. Screen shot is attached. but it happened once

Click to expand...

Are you using Hardware Serial COM port or using a USB to COM Port Converter?
If you are using Hardware Serial COM Port, than just open Hyper Terminal and select COM Port 1 or 2 what ever you have, and than set Properties like as
9600, 8 Bits, None Parity, 1 Stop Bit, None Flow control. Your PC COM Port Ground must be common with SIM300 Dev Board Ground.

And set jumper according to my uploaded snap of P3 jumpers, for SIM300 and PC Interface. And Click Connect Button (Or it Already Connected) (You may download Br@y++ Terminal from **broken link removed** for professional use)

Than Power ON your SIM300 Board, If you get RDY status than you got your real status and it is ready for use. If you didn't got RDY status than their is still some problem.

If found problem, than you need to check your COM Port First with an LED and a resistor in series and by removing COM Port DB9 Connector from SIM300 Dev Board. Connect a LED and Resister in series. LED Anode must connect to Resistor and LED Cathode should be connected to common Ground. and Resistor open wire must be connect to PC COM Port Tx Pin 3 (see attached picture) .

Now use Hyper Terminal or Br@y++ Terminal (PC COM Port Only connected to LED circuit) and after connection Send some thing (text) and than observe LED blinking, it should be very fast (Visible in Dark room).

If you found PC COM Port OK than do the same procedure with LED for SIM300 Dev Board after MAX232 IC (means Dev Board DB9 connector). This will helps you to troubleshoot your whole scenario

Serial Cable and COM port1 is working fine. I used Br@y++ terminal. it gives <0> s. after entering the "AT" it gives some syntax. but didn't get a rdy command

---------- Post added at 15:20 ---------- Previous post was at 15:19 ----------

<0> display rate is equal to LED blinking frequency

<0> display frequency equals to LED blinking rate. BR@Y++ terminal output attached

Hi guys,

I've been following this thread all day since I've been having the same problem with the same piece of hardware. Try a baud rate of 19200 using Br@y++. This actually gives me

"
RDY

+CFUN: 1

+CPIN: READY

Call Ready

"

Rather than just gibberish on boot up

hi,
Could you please tell me the other parameters?

Sure...
-----------
Com Port: Port 4 (This might be different depending where you plugged into your PC)

Baud Rate: 19200

Data bits: 8

Parity: None

Stop Bits: 1

Handshaking: None (I tried the other options, but the all seemed to cause Br@y++ to crash)
-----------

Also, leave the board unplugged, set up the connection and connect. THEN, plug the board in, press the power button, then press and hold the other button (not sure what it's called) for a couple of seconds before releasing. Then you should get the RDY, +CFUN: 1 ...

I haven't had any luck with issuing the AT commands yet (no reponse) but at least I can read something back from the board!

I think my module is not working. Didn't get a RDY command. It displays only unidentified characters. tried with other baud rates up to 19200. but didn't get a reply. Thank you masterleous, and SthAusGuy for spend their valuable time.

If you are getting other response like RDY and etc etc, than your modem is ready to communicate with you, The only need is to check the SIM registration to network. NETLIGHT LED or NETLIGHT Pin gives you the status, If you are getting CALL READY message than SIM is registered, one more thing check VRTC pin, it must be connected to some battery or to a capacitor of upto 4.7uF. Otherwise you will get problem.

You are getting almost all response, except for the AT response, Check PC Tx connection to SIM300 Rx connection. i think SIM300 is not getting 'AT' Command from PC anymore.

First of all powered off your whole thing and than check above mentioned connection. In my observation SIM module is not getting 'AT' command from PC

---------- Post added at 19:55 ---------- Previous post was at 19:53 ----------

sahancr said:

I think my module is not working. Didn't get a RDY command. It displays only unidentified characters. tried with other baud rates up to 19200. but didn't get a reply. Thank you masterleous, and SthAusGuy for spend their valuable time.

Click to expand...

Had you checked Tx and Rx pins of SIM300 module, do LED test with the Tx pin of SIM300 module without connecting it to PC. and power ON and press push buttons to give ON command. Check LED status. From this way you will troubleshoot the main problem

It is working. Thank you very much for your kind support

---------- Post added at 11:15 ---------- Previous post was at 11:14 ----------

Baud Rate is 115200

Great to hear Sahancr! What did you do differently?

Can you also post the jumper positions you're using?

Perhaps you can help with my problem. As before, I get the...
"
RDY
+CFUN: 1
+CPIN: READY
Call Ready
"
However, I don't get any response using Putty, Hyperterminal or Br@y++ terminal.

I've done a loop back test using the serial cable plugged into the back of my computer and with the USB-to-serial cable that came with the part. Both cables seems to work and I see the echo in all the terminals.

However, when the board is plugged in and/or powered up, I get nothing.

Any suggestions? Masterleous, you suggested
"Had you checked Tx and Rx pins of SIM300 module, do LED test with the Tx pin of SIM300 module without connecting it to PC. and power ON and press push buttons to give ON command. Check LED status. From this way you will troubleshoot the main problem "

Can you please discribe that again, I don't quiet follow...

Input Voltage : 8.0V
Input Current : 700mA

Jumper Settings
P1 - 2-4
P3 - 1-3 AND 6-8

Insert SIM Card

Then power up the module using Power on button.

System LED (Red) : ON
Net LED (Green) : Blinks few seconds and then OFF

It means SIM card is registered to Network.

Then your Module is ready to transmission

I used Micro IDE Terminal

Baud Rate : 115200

PORT : COM1

Data bits: 8

Parity: None

Stop Bits: 1

Handshaking: HARDWARE

Then connect it to the module.

:
AT

OK

(then I gave a call to SIM Card.)

RING

NO CARRIER
(Function LED is Blinking (Middle RED LED))

ATE0

OK

AT + CMGF = 1

OK

AT + CSCS = "GSM"

OK

AT = CMGS = "YOUR MOBILE NUMBER"
> (TYPE YOUR MESSAGE)

+ CMGS: 179

OK

(Change Baud Rate)

IT + IPR = "9600"

OK

After changing the baud Rate you need to connect it again.

I have attached my microcontroller source code for sms sending. please refer it also.

Micro Controller - PIC16F877A
Crystal : 4MHz

Masterleous suggested to me to check the Tx pin of the module. I got a result when I was power on the module.

---------- Post added at 15:43 ---------- Previous post was at 15:42 ----------

This is the Micro Controller Code
Used Micro C PRO

//#include <uart1.h>//
#include <built_in.h>
char uart_rd;

void main() {

UART1_Init(9600); // Initialize UART module at 9600 bps
TRISB = 0;
PORTB = 0;
Delay_ms(3000); // Wait for UART module to stabilize


UART1_Write_Text("AT+CMGF=1\r"); //text mode
PORTB = 1;
Delay_ms(3000);
UART1_Write_Text("AT+CSCS=\"GSM\"\r");
PORTB = 0;
Delay_ms(3000);
UART1_Write_Text("AT+CMGS=");
PORTB = 1;
Delay_ms(3000);
UART1_Write_Text("\"Mobile No\"\r");
PORTB = 0;
Delay_ms(3000);
Delay_ms(3000);
//if((modem_Check(">",1)==0))
UART1_Write_Text("MESSAGE");
PORTB = 1;
Delay_ms(3000);
//UART1_Write_Text("\r\x1A");
UART1_Write(0x1A);
PORTB = 0;
Delay_ms(3000);




/*while (1) { // Endless loop
if (UART_Data_Ready()) { // If data is received,
uart_rd = UART_Read(); // read the received data,
UART_Write(uart_rd); // and send data via UART
}
}*/
}

Thanks for the config sahancr

That was pretty much my set up too. I've been using 12v, 1amp as per the manual though.

I've tried a few other things since my last post. Attempting to call/sms the board works, however since no AT commands are acknowledged, I can't accept calls or send SMSs.

I've used several different terminal programs incase the CR may have been a problem & several different sims but with no success.

The PC-MCU setup has no problem transmitting from my PC to my arduino. Like you said Masterleous, I think the SIM module is not receiving the commands. It would be good to test this, but I don't think I can get to the Sim Tx to do a LED test without damaging the board.

Also, this seems to be a common problem:
https://www.edaboard.com/threads/225112/

How about your Green LED status when power ON?