Problem with Rx UART port with GPS module

[samus111]

Good day
I have a problem that still I have not been able to figure out what is the root of the problem. I want to communicate a Iridium GPS module with a PIC (does not matter the Pic family, I only need that be able to communicate, and that be the most small as possible) I attach the code:

[ezflyr]

Hi,

No offense, but your 'C' code is some of the worst I've ever seen posted on the forum in a long time..... As another user recently said "I found myself gently retching in the corner" while reading it.... Clearly, based on your posted code, you haven't spent a lot of time browsing the forum archives, or studying the CCS provided example programs, to try to learn 'proper' 'C' language coding......

First of all, can you post a link to the 'GPS' module that you are using. Before proceeding, we need to know the interface specifications, the baud rate, etc. Also, are you sure this is a GPS project? You code doesn't seem to be written to read/interpret typical GPS data. Frankly, it seems more like a GSM project to me.

As to your code, there are lots of problems. First, for reliable data reception via the hardware UART, you really should be using a serial interrupt to receive data. Look at the example program 'ex_sisr.c' to see how this is done properly. You also need to add the 'Errors' keyword to your #use rs232 directive to prevent the UART from locking up if an over-run condition occurs..... This has been covered many, many times before! You use of 'goto's' is really poor 'C' form, and should be avoided if possible. All of your 'goto's' can be replaced with other constructs, such as 'Do-While' loops..... Finally, your formatting is terrible. Learn to write code with proper indenting, so as to be easily readable.

Your #fuses are a bit on the light side. Many fuses default to the desired value, but for critical ones, I like to explicitly state them. Examples would be the 'NOLVP', and the 'NOWDT' fuses.

John

[ckielstra]

In addition to all the above:

[samus111]

ok

[samus111]

sorry, I am a beginner in CCS codes, but I like that you be so honest, Ok I will take the changes you have advised me, I will run again the program and I will answer in few minutes, Thanks (the range error, was a modification that I made for look something, and I forgot to return it to it real value)

[samus111]

For other side, the device is not a GPS module, is a Iridium module (IRIDIUM MODULE 9603), so, this one only takes a message from a manufactured device, and send them to the Iridium network, for later, be received in a email account. In this case, I want to send the message :Hola Mundo. the device, first must be activated by the command "AT", after this, the device will answer with a OK, later, I must to write the message in the module memory, then, I must to send the command "AT+SBDWT:(my text is here)". With this, the Module will answer with a OK, and I have to go with the third command, but in this part, the PIC does not recognize the OK answer from the module. I will take in mind your tips, I will answer soon today.

[ezflyr]

Hi,

Just out of curiosity, why did you chose this for your topic title, "Problem with Rx UART port with GPS module", if this is not a GPS project?

Rather that reading the module communications requirements to us, please post a link to the exact module you are using, as requested in my 1st reply!

John

[samus111]

You are right, the true is that, the message I send by the iridium network, the idea is to send a GPS coordinate obviously gotten through a GPS module (I will use the L70 quectel GPS module), that's why my project is a GPS position sender, but the first part, I try to communicate the module with the PIC , and I am having problems here. Thanks

[ezflyr]

Hi,

OK, but you've now ignored two requests that you post a link to the module that you are interfacing to the PIC, so I'm going to abandon this thread. Without the requested data you are just wasting everybody's time. If you come here asking for help, you really should be willing to cooperate with any requests for additional information that are made.....

Good Luck!

John

[samus111]

but I answered before, the module is a IRIDIUM 9603, that is its name, do you need that I attach a file??

[ezflyr]

Hi,

You've come here asking for our help, so you should make it as easy for us as possible to help you. That means if there are any pertinent documents to help us, you should post links so that we can easily find them. In this case, at a minimum, we would need to see the module datasheet so that we could verify the hardware interface. We would also need to see the (AT) command reference so that we could see how to 'talk' to the module, and make it work as intended. Your interpretations of these documents are not good enough, and we should not be expected to have to go search for them on our own.

John

[temtronic]

As John says, we need more information...

one HUGE problem could be the 'interface'. Most, if not all GPS devices run on 3 volts and the PIC is a 5 volt device. That alone is a big problem !!

hth
jay

[samus111]

ok Jhon, and sorry, I am new in this forum, and I need to learn the procedure, Thanks for you help:
here is the developer guide:
http://www.pacificrim.com.au/media/custom/upload/File-1383622151.pdf

I have the AT Acommands in a pdf file, but I do not know how share it here, there is a way?

I think the problem is some issue with the schmitt trigger, but I am not sure, how can I configure the schmitt trigger in my 16f688?

[dyeatman]

The developers manual says the default RS232 data rate is 19200...not 9600
It also says the module acts as DCE.
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[samus111]

Of course, I set the baud rate to 9600 in the module before (that is the baud rate of the GPS module too) and I stored that baud rate in a user profile, so always when the device starts, is transmitting and receiving to 9600.