Author Topic: GSM module with SPI interface  (Read 316 times)

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Offline hussamaldean

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GSM module with SPI interface
« on: September 13, 2019, 06:27:49 am »
Hi all,
I am looking for GSM module for my project which needs a GSM. however, the RS232 is slow and requires a lot of time. is there any GSM module that uses SPI interface rather than RS232 ?

regards
« Last Edit: September 13, 2019, 06:52:04 am by hussamaldean »
 

Offline Phoenix

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Re: GSM module with SPI interface
« Reply #1 on: September 13, 2019, 07:34:43 am »

It's been my experience that the modules will use a UART as they follow the 3gpp standards. Modules with USB will present themselves as virtual comm ports to an OS. Can you use UART with flow control for extra speed?

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Offline hussamaldean

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Re: GSM module with SPI interface
« Reply #2 on: September 13, 2019, 08:27:16 am »

It's been my experience that the modules will use a UART as they follow the 3gpp standards. Modules with USB will present themselves as virtual comm ports to an OS. Can you use UART with flow control for extra speed?

Sent from my G8441 using Tapatalk
we have 3G in only in Iraq, the problem I need to send data at rate of 1Hz but the module can't processor fast enough the AT commands, the delay is about 400mS between each AT command and burst data doesn't work either since the server will kick me out :(
 

Offline Phoenix

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Re: GSM module with SPI interface
« Reply #3 on: September 13, 2019, 08:52:21 am »
I don't think the cellular system is designed for that kind of real time data transfer.

You can usually enter a raw data transfer mode once your socket is open. Then continually send data. Are you saying the server disconnects your socket if you do that?

 Can you aggregate data and send a minutes or 5 minutes worth in batches?

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Offline hussamaldean

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Re: GSM module with SPI interface
« Reply #4 on: September 13, 2019, 09:02:34 am »
I don't think the cellular system is designed for that kind of real time data transfer.

You can usually enter a raw data transfer mode once your socket is open. Then continually send data. Are you saying the server disconnects your socket if you do that?

 Can you aggregate data and send a minutes or 5 minutes worth in batches?

Sent from my G8441 using Tapatalk
the main purpose is to monitor a remote substation in real time which requires to send data every 1 seconds but the GSM module requires about 1 seconds to process each AT command :(
 

Offline Phoenix

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Re: GSM module with SPI interface
« Reply #5 on: September 13, 2019, 09:16:14 am »
Have you tried putting it into data pass through mode, assuming your module supports it. You don't need to use at commands then. Whatever you send down the rs232 is directly sent out the socket, without wrapping in an AT command. Can send data a lot faster.

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Offline hussamaldean

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Re: GSM module with SPI interface
« Reply #6 on: September 13, 2019, 01:13:43 pm »
Have you tried putting it into data pass through mode, assuming your module supports it. You don't need to use at commands then. Whatever you send down the rs232 is directly sent out the socket, without wrapping in an AT command. Can send data a lot faster.

Sent from my G8441 using Tapatalk

does the sim900 support it ? if yes, how to enable it ?
 

Online FreddieChopin

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Re: GSM module with SPI interface
« Reply #7 on: September 13, 2019, 08:08:08 pm »
If that's the case then maybe ditch GSM altogether and go with customized shortwave RF link?
 

Offline Phoenix

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Re: GSM module with SPI interface
« Reply #8 on: September 13, 2019, 10:21:52 pm »
Called transparent mode. Search for SIM900_TCPIP_Application Note_V1.02.pdf

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« Last Edit: September 13, 2019, 10:25:44 pm by Phoenix »
 

Offline hussamaldean

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Re: GSM module with SPI interface
« Reply #9 on: September 14, 2019, 04:41:16 am »
If that's the case then maybe ditch GSM altogether and go with customized shortwave RF link?
It is not possible to use shortwave since the requirement is to  use GSM
Called transparent mode. Search for SIM900_TCPIP_Application Note_V1.02.pdf

Sent from my G8441 using Tapatalk

I tried to use CIP mode but since I have to send JSON data, it won't work
 

Online blueskull

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Re: GSM module with SPI interface
« Reply #10 on: September 14, 2019, 04:56:58 am »
My friend, nobody mades just GSM/3G/4G modem module chips anymore. They are all cellphone SoCs running a special firmware.

They are, at least, fast enough to handle any UART data you throw at them. The only reason they wait before returning to your command, is because they have to wait for the cellular transmission.

Therefore, spare your energy on finding a faster communication between modem and MCU.
 

Online FreddieChopin

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Re: GSM module with SPI interface
« Reply #11 on: September 14, 2019, 07:25:40 am »
From your rather stange reqirements it sounds more and more like you're trying to develop something shady that involves lots of fertilizer  :palm:
 


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