GPS evaluation board and GPS receiver

[ober]

Ok my GPS unit is working. MAX circuit has already been implemented in the system. However, when i set printf("%c",(RXDATA)), weird numbers and charactors appear. Any idea how to resolve this problem?

What is the baud rate you are communicating?
You are printing each character to LCD? In that case, you are using loop?

you might need to check out the post over here http://forum.cytron.com.my/viewtopic.php?f=9&t=10370&start=20

[powerman]

Hi Moderator,

I got the thing working =) thanks for all your help. One more question. How do i only display one message all the time, as i dont need the other message as it overflows my serial buffer and cause missing charactors from the GPS. Can i have the exact command? i only need GPGGA or GPRMC. Looking forward to your quick reply

[ober]

I got the thing working =) thanks for all your help. One more question. How do i only display one message all the time, as i dont need the other message as it overflows my serial buffer and cause missing charactors from the GPS. Can i have the exact command? i only need GPGGA or GPRMC. Looking forward to your quick reply

Good to hear most of the thing is working well. As for your question we have actually reply it in the product inquiry section under the GPS module product page:

Yes, you can do that by using the miniGPS software. But please take note that you will need a backup battery in order to retain the setting after power off the module.

Hope this help and do share with us about your project, a few photos on your hardware will motivate more people!

[Jiewy]

I will submit in my project here. LOL after i am done. xD

Ober i think u better give him the latest minigps to do the settings? Be warn powerman, u only have like 7 times to save the settings to ur flash memory of ur gps module before it gets fried. Fried = dead = Rm575 to rubbish bin...

Powerman or ober, wat kind of max 232 circuit do i have to implement into my MCU?

I mean i am current using the one that the datasheet is showing me, which uses max232 chip and three 0.1uF capacitors. I am using these connection but i am getting rubbish on my lcd! Should i follow the one from the provided datasheet or the one i can find in the internet?

P.S. I changed the baudrate to the same already, so i dont think its baudrate problem..

[ober]

I mean i am current using the one that the datasheet is showing me, which uses max232 chip and three 0.1uF capacitors. I am using these connection but i am getting rubbish on my lcd! Should i follow the one from the provided datasheet or the one i can find in the internet?

3 0.1uF cap, but normally we are using at least 4 cap + 1 cap for the 5V input. Which max 232 IC you are using? And which connection you are using?

Anyway just want to verify with you, are connection GPS from GPS Evaluation board to PIC Microcontroller?

[Jiewy]

3 0.1uF cap, but normally we are using at least 4 cap + 1 cap for the 5V input. Which max 232 IC you are using? And which connection you are using?

Anyway just want to verify with you, are connection GPS from GPS Evaluation board to PIC Microcontroller?

Yes, The connection is from GPS eval board to PIC.
I looked through the datasheet that can be downloaded from the cytron website,

http://www.cytron.com.my/viewProduct.ph ... lgMWYzw7s=

Its under the 'schematic' download section.

There i saw the Max232 connection using 3 0.1uF. and yea i saw my frens all use like wat u said more than 3 caps one.. so i am really not sure which one i should use.

If that is not the right connection can u send me a schematic that works?

[waiweng83]

Ober i think u better give him the latest minigps to do the settings? Be warn powerman, u only have like 7 times to save the settings to ur flash memory of ur gps module before it gets fried. Fried = dead = Rm575 to rubbish bin...

For those who wants to save the setting permanently to the flash, you can download the latest miniGPS version from here: http://www.gpsking.com.tw/ezfiles/eni/i ... S_1.41.zip. But just as what Jiewy said, you can only write to the flash for 7 times. So please use with care.

There i saw the Max232 connection using 3 0.1uF. and yea i saw my frens all use like wat u said more than 3 caps one.. so i am really not sure which one i should use.

If that is not the right connection can u send me a schematic that works?

The circuit really depends on which MAX232 chip are you using. The chip used in the GPS evaluation board is 3.3V version, thus the circuit might be different. Please refer to the datasheet of the MAX232 chip that you are using. It should have the example connection.

[Jiewy]

So boss, it doesnt matter if i am using MAX232CPE or MAX232ECWE(gps datasheet). They are all can be used as long as i get the schematic right?

[ober]

Please don call boss.....

it doesnt matter if i am using MAX232CPE or MAX232ECWE(gps datasheet). They are all can be used as long as i get the schematic right?

Em..... if you notice, different chip have different specs. The GPS evaluation board uses 232ECWE because it is 3.3V UART. While other use 232CPE because it is 5V UART. So if you are interfacing with 5V PIC, you should choose 5V chip.

[Jiewy]

Ii am using PIC16f877a which read TTL(5V). I will have to use a max232cpe like wat u said earlier on. May i know the voltage logic level for the gps side?