Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Use one UART for both GSM and GPS of sim908 ??

Status
Not open for further replies.
T

ThiVu

Junior Member level 2
Joined
Aug 1, 2011
Messages
21
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,283
Activity points
1,427
Hi all,
I am using module sim908 in my project.
I want to know whether I use the same module UART of MCU for both GMS and GPS module of sim908.
Now, GSM module work well (can send/read sms, make voice call ...).
But I send "AT+CGPSPWR=1" to power up GPS then the modem do not respond anything.
Thank you!
 

Hi. I solved this problem. Now I use GSM and GPS with only one module UART.
I faced another problem. This is my command sequence:
send:AT

recv: 6

OK


send:AT+CSQ

recv: 20

+CSQ: 22,0



OK


send:AT+GSV

recv: 65

SIMCOM_Ltd

SIMCOM_SIM908

Revision:1137B03SIM908M64_ST



OK



send:AT+CGPSPWR=1

recv: 6

OK


send:AT+CGPSRST=0

recv: 6

OK


send:AT+CGPSOUT=255

recv: 6

OK


send:AT+CGPSIPR=115200

recv: 6

OK


send:AT+CGPSSTATUS?

recv: 39

+CGPSSTATUS: Location Unknown



OK


send:AT+CGPSINF=32

recv: 67

32,000054.001,V,0.000000,N,0.000000,E,0.00,0.00,101010,,E,A

OK

--------------------------------
I received respond form CGPSSTATUS: Location Unknown
And data from CGPSINF seem to be invalid.
Could you help me to solve this.
Maybe I make mistake or forgot some command??
Thank you
 

ThiVu said:
Hi all,
I am using module sim908 in my project.
I want to know whether I use the same module UART of MCU for both GMS and GPS module of sim908.
Now, GSM module work well (can send/read sms, make voice call ...).
But I send "AT+CGPSPWR=1" to power up GPS then the modem do not respond anything.
Thank you!
Click to expand...

Hi, Thivu, GPS use pin15 & 16

---------- Post added at 16:49 ---------- Previous post was at 16:43 ----------
ThiVu said:
Hi. I solved this problem. Now I use GSM and GPS with only one module UART.
I faced another problem. This is my command sequence:
send:AT

recv: 6

OK


send:AT+CSQ

recv: 20

+CSQ: 22,0



OK


send:AT+GSV

recv: 65

SIMCOM_Ltd

SIMCOM_SIM908

Revision:1137B03SIM908M64_ST



OK



send:AT+CGPSPWR=1

recv: 6

OK


send:AT+CGPSRST=0

recv: 6

OK


send:AT+CGPSOUT=255

recv: 6

OK


send:AT+CGPSIPR=115200

recv: 6

OK


send:AT+CGPSSTATUS?

recv: 39

+CGPSSTATUS: Location Unknown



OK


send:AT+CGPSINF=32

recv: 67

32,000054.001,V,0.000000,N,0.000000,E,0.00,0.00,101010,,E,A

OK

--------------------------------
I received respond form CGPSSTATUS: Location Unknown
And data from CGPSINF seem to be invalid.
Could you help me to solve this.
Maybe I make mistake or forgot some command??
Thank you
Click to expand...

Hi, Thivu,
Pls try to send AT+CGPSRST=1 instead of AT+CGPSRST=0
 

Hi ThiVu,
Does your GPS antenna have a clear line of view to the sky (satellites) (Try it outdoors.)
Gps Reset: 0 --> rst in Cold start Mode , 1 --> rst in autonomy mode (try both) ... Not likely though...
Did you solved it... Please share your solution ;D
Rod
 

I have an application to use this module sim908 in a forest. far away from city but sky is clearly seen. Would the module function?
 

Echo wang said:
Sure, dear!
Click to expand...

jurst to be sure.. given a clear sky, can a gps track location of any country in the world? I live in SL, so anywhere!! literally! be tracked?
also with regard to SIM908, is it bad to switch on the SIM908 module without connecting antenas? would it damage the module?
 

Amalinda said:
jurst to be sure.. given a clear sky, can a gps track location of any country in the world? I live in SL, so anywhere!! literally! be tracked?
also with regard to SIM908, is it bad to switch on the SIM908 module without connecting antenas? would it damage the module?
Click to expand...

Hi, SIM908 need antenna to fix the location.
 
hi Amalinda,

yes, it is possible to use GPS literally anywhere in the world with GPS given that the module is receiving proper signals...
I've tried several GPS modules in many places around Sri Lanka, which were bought from ebay.
GPS satellites have covered the whole world!


Without the antenna, the RF power generated by the module reflects back to the source. Just think about an open ended transmission line.
Depending on the length of the transmission line, the built up voltage levels at the source varies. So, there's a probability of damaging your module.

Generally, it's a good idea (i would say a rule of thumb) to connect a proper antenna for any kind of RF transmitter/transceiver before turning it on.

If there's only a receiver, there's no chance to damage the device without an antenna since it's not transmitting RF signals.
Since SIM908 is a transceiver, always good to have an antenna connected before power it up...
 
Last edited:
Echo wang said:
Hi, SIM908 need antenna to fix the location.
Click to expand...

thank you.

- - - Updated - - -

per_lube said:
hi Amalinda,

yes, it is possible to use GPS literally anywhere in the world with GPS given that the module is receiving proper signals...
I've tried several GPS modules in many places around Sri Lanka, which were bought from ebay.
GPS satellites have covered the whole world!


Without the antenna, the RF power generated by the module reflects back to the source. Just think about an open ended transmission line.
Depending on the length of the transmission line, the built up voltage levels at the source varies. So, there's a probability of damaging your module.

Generally, it's a good idea (i would say a rule of thumb) to connect a proper antenna for any kind of RF transmitter/transceiver before turning it on.

If there's only a receiver, there's no chance to damage the device without an antenna since it's not transmitting RF signals.
Since SIM908 is a transceiver, always good to have an antenna connected before power it up...
Click to expand...


thank you.
 

Hi ThiVu

In my project is using sim908. Are You send comand AT for GPS via pins 68 and 71 (68:GsmRXD 71:GsmTXD ) ?

if I have to use both UART of sim908 need a MCU with 2 UART

thank you

-------------------------------------------------------------------------------------


ThiVu said:
Hi. I solved this problem. Now I use GSM and GPS with only one module UART.
I faced another problem. This is my command sequence:
send:AT

recv: 6

OK


send:AT+CSQ

recv: 20

+CSQ: 22,0



OK


send:AT+GSV

recv: 65

SIMCOM_Ltd

SIMCOM_SIM908

Revision:1137B03SIM908M64_ST



OK



send:AT+CGPSPWR=1

recv: 6

OK


send:AT+CGPSRST=0

recv: 6

OK


send:AT+CGPSOUT=255

recv: 6

OK


send:AT+CGPSIPR=115200

recv: 6

OK


send:AT+CGPSSTATUS?

recv: 39

+CGPSSTATUS: Location Unknown



OK


send:AT+CGPSINF=32

recv: 67

32,000054.001,V,0.000000,N,0.000000,E,0.00,0.00,101010,,E,A

OK

--------------------------------
I received respond form CGPSSTATUS: Location Unknown
And data from CGPSINF seem to be invalid.
Could you help me to solve this.
Maybe I make mistake or forgot some command??
Thank you
Click to expand...

- - - Updated - - -

Hi ThiVu

In my project is using sim908. Are You send comand AT for GPS via pins 68 and 71 (68:GsmRXD 71:GsmTXD ) ?

if I have to use both UART of sim908 need a MCU with 2 UART

thank you

-------------------------------------------------------------------------------------


ThiVu said:
Hi. I solved this problem. Now I use GSM and GPS with only one module UART.
I faced another problem. This is my command sequence:
send:AT

recv: 6

OK


send:AT+CSQ

recv: 20

+CSQ: 22,0



OK


send:AT+GSV

recv: 65

SIMCOM_Ltd

SIMCOM_SIM908

Revision:1137B03SIM908M64_ST



OK



send:AT+CGPSPWR=1

recv: 6

OK


send:AT+CGPSRST=0

recv: 6

OK


send:AT+CGPSOUT=255

recv: 6

OK


send:AT+CGPSIPR=115200

recv: 6

OK


send:AT+CGPSSTATUS?

recv: 39

+CGPSSTATUS: Location Unknown



OK


send:AT+CGPSINF=32

recv: 67

32,000054.001,V,0.000000,N,0.000000,E,0.00,0.00,101010,,E,A

OK

--------------------------------
I received respond form CGPSSTATUS: Location Unknown
And data from CGPSINF seem to be invalid.
Could you help me to solve this.
Maybe I make mistake or forgot some command??
Thank you
Click to expand...
 

fighter_ar said:
Hi ThiVu

In my project is using sim908. Are You send comand AT for GPS via pins 68 and 71 (68:GsmRXD 71:GsmTXD ) ?

if I have to use both UART of sim908 need a MCU with 2 UART

thank you

-------------------------------------------------------------------------------------




- - - Updated - - -

Hi ThiVu

In my project is using sim908. Are You send comand AT for GPS via pins 68 and 71 (68:GsmRXD 71:GsmTXD ) ?

if I have to use both UART of sim908 need a MCU with 2 UART

thank you

-------------------------------------------------------------------------------------
Click to expand...

Pls offer your e-mail, I can send to you.
 

Hi,

I'm using SIM908 in a project. The module connects well with the GPRS. But when I turn on the module and reset it cold start mode it goes back to autonomy mode. That's why it isn't picking up my location.

My command sequence is this:

Code: 
GPRS_cmd("AT+CGPSPWR=1\r\n");
delay_ms(5000);

GPRS_cmd("AT+CGPSRST=0\r\n");
delay_ms(1000); 

GPRS_cmd("AT+CPSRST?\r\n");
delay_ms(500);

GPRS_cmd("AT+CGPSINF=0\r\n");
delay_ms(2500);

GPRS_cmd("AT+CGPSSTATUS?\r\n");
delay_ms(500);
thanks in advance.
 

Just use
AT+CGPRST = 0
and geive a delay of at least 20 to 30 seconds then only give
AT+CGPSINF= 0
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top