Matrix user forums

Hi,

I just recieved my GPS Chip the UP501 from Fastrax.
I have connected it all up and downloaded the example file to show me the time and date.

The problem is there is no data displayed.

After 3 to 5 minutes pin 6 (PPS) activates and the LED is blinking, according to the datasheet:

4.5 PPS
The pulse-per-second (PPS) output provides an output for timing
purposes. There is a 100ms pulse once per second synchronized to
UTC second at rising edge when the receiver has a valid 3D position
fix available.

Datasheet of the Device: http://www.fastraxgps.com/showfile.cfm? ... 0234006b29

When the LED blinks the reciever has an stable fix, does that mean the reciever is recieving data?

Also I read that:

4.4 UART
The device supports UART communication via Port 0 of the GPS IC.
With the standard firmware the Port 0 is configured by default to
NMEA protocol (9600 baud).
I/O levels at the serial ports are CMOS compatible (see table 1). Onboard
RS232 level converter is available with the Fastrax UP501R
module.

What does that mean CMOS, arent CMOS and RS232 two different signal levels.

Can somebody help me with this, I cant get it to work.
Also I have checked if the TX and RX lines are connected wright and they are

I have made a little video thats shows what kind of problem im having.

http://youtu.be/MSrRKQ21TKw

I all,

I want to give you guys an update,
I have connected the GPS chip to my RS232 to USB Eblock an connected that to my PC.

The results where fantastic , the GPS chip works fine.
Now the question is why not with the macros,

I have double checked the connectection and they where OK









Please can somebody help me to get this working with my microcontroller !!!

Thanks in advance.

Regards Jordy Kleian

Hi jordy
i havent got a gps module but i did a quick search and found one of john crows old posts you could try his code in the following thread and see if it works for you hth http://www.matrixmultimedia.com/mmforum ... gps#p26303

dazz wrote:Hi jordy
i havent got a gps module but i did a quick search and found one of john crows old posts you could try his code in the following thread and see if it works for you hth http://www.matrixmultimedia.com/mmforum ... gps#p26303

thanks for your reply I have already tested his software, but it makes no difference.
I don't know what the problem is, I also tried to change the baud rate but that dint help much.

hope that you and others have more ideas to test

Regards Jordy

Hi Jordy

Just tried the flowcode file you posted, it doesnt work with my e-block either
Though it looks the same as the file I have that works.
Do you want to try this one.

Where did you get the SkyTraq software from? Looks like an interesting package ?

Hi John,

This is the software that I'm using: http://elecfreaks.com/store/download/da ... 101116.zip

Im now testing your flowcode hope that is works, I will let you know.

Regards Jordy

JohnCrow wrote:Hi Jordy

Just tried the flowcode file you posted, it doesnt work with my e-block either
Though it looks the same as the file I have that works.

GPS Time and Date V1.fcf

Do you want to try this one.

Where did you get the SkyTraq software from? Looks like an interesting package ?

John,

I have tested your software but still no information is displaying on the LCD
I dont know what going on here.

Jordy

Hi
Ive just looked at the data sheets.
The UP501 is certainly looks compatible with the UP500 which the Matrix E-Block uses. So you would expect it to work the same.
If you have used the module through rs232 then you know at least that it is working ok.
Maybe Benj can throw some light on it when they open on Monday.

JohnCrow wrote:Hi
Ive just looked at the data sheets.
The UP501 is certainly looks compatible with the UP500 which the Matrix E-Block uses. So you would expect it to work the same.
If you have used the module through rs232 then you know at least that it is working ok.
Maybe Benj can throw some light on it when they open on Monday.

I hope that Benp or others from the matrix team can solve this problem, I dont know if its a bug or something,
But as you noticed:

The GPS chip works perfect so that isent the problem, I could use a nother IC to try but I dont think that is the problem.

I will wait until monday,

Thanks again john,

Regards Jordy

Hi jordy
ive only had 4 hours sleep in the last 2 days so this reply might not make sense, had a scan through the manuals and as you said your module outputs cmos levels, the pic operates at ttl level, so maybe some sort of level converter may be required, i noticed that the rs232 board has a level converter on it as you are using it to interface to pc, you may be able to utilize this by connecting it between the pic and gps module (please read and triple read all the relevant data sheets as i wont be responsible if it goeswrong and destroys your neighbours dog ) , might be something worth looking into hth

Hello,

My guess is that the reason the GPS component is not working is that you may have your clock speed or a configuration setting setup incorrectly in Flowcode which is resulting in an incorrect baud rate which is resulting in no data received.

Have you done the basic 1hz flasher test on your hardware to check everything is setup correctly?

Are you powering the VBATT pin on the GPS module. I found that if this was left disconnected on some GPS devices that the GPS failed to startup.

TTL and CMOS basically describe the technology and should be compatible in this case, I'm guessing both devices are running at 3.3V?

Hope this helps.

Benj wrote:Hello,

My guess is that the reason the GPS component is not working is that you may have your clock speed or a configuration setting setup incorrectly in Flowcode which is resulting in an incorrect baud rate which is resulting in no data received.

Have you done the basic 1hz flasher test on your hardware to check everything is setup correctly?

Are you powering the VBATT pin on the GPS module. I found that if this was left disconnected on some GPS devices that the GPS failed to startup.

TTL and CMOS basically describe the technology and should be compatible in this case, I'm guessing both devices are running at 3.3V?

Hope this helps.

Hi Benj,

I have made a one second flasher in the GPS program and it the led flashes every 1.002 second. So I can say that the clock frequency is set wright.
The GPS chip is working OKE, as you can see in the above images. The connection to the pic microcontroller are correct.
Also the GPS is outputting serial data.

The GPS is working of 3.289 Volts, the microcontroller is working on 5.04 Volts.

hope you have any ideas Benj.

Regards Jordy

Hello Jordy,

Ah I think I see the problem. A normal 5V PIC can read a voltage of 3.3V on a input pin as a logic 1. However the UART is less tolerant and so will probably not be detecting the logic 1 on the input. I have come across this problem before.

I think you have three options.

1) Run the GPS module at 5V. Probably not an option if the GPS cannot run over 3.3V.
2) Run the PIC at 3.3V. May not be an option if your using say our EB006 multi-programmer board.
3) Use a level shifter IC or a transistor to convert the voltage levels from 3.3V to 5V. You only really need the tx data from the GPS (rx on the micro) to be level shifted and allow the Flowcode component to work as the component does not talk back to the GPS device.

Hi benj,

Super Super thanks for your reply, I built a voltage shifter out of transistors and it works awesome.
Thank you so much,

O by-the-way the article (document) that i'm wrighting is for the first part half-way done.
Would you like a preview.

Let me know,

Anyway thank you

Regards Jordy

Pleased to hear you've got it sorted

Benj or others,

My GPS is working correctly, but every time one problem gets solved another gets created.

My RS232 to USB board was connected to PORT.C because there is the hardware UART located. I need to change to a different port because its better that the GPS uses the hardware UART because of the amount of information that been received.

For the RS232 to USB board to work I have moved it to PORT.B the reason for this is that INTB0 is located there, INTB0 is connected to the receiving pin so every time the system receives some information a macro gets called.

The problem here is that when I send information via the PC to my micro controller the controller freezes. but when I look with my scoop on the receiving pin you can clearly see signals passing when I click the request to send button.

Also when I'm not using the interrupt but just put the receiving info macro into the mean program loop, the controller doesn't freeze but data won't be displayed no matter how many times a press the request to send button.

This is the nice part, when I connect the RS232 to USB board to the hardware UART everything works like a dream.

I hope somebody can help me again

If you need the program just say soo

Regards Jordy

PS. I not able to respond this week between 6.00 to 18.00 Sorry

Hi, all

I have been working on the RS232 to USB problem that I'm having, but I cant figure out what the cause is.

I know that I need to use the software UART but for the micro controller to respond on incoming information i need to use a interrupt.
As i described above I used INTB0 to do this, but I can't receive any information, wen I look with my scoop I can clearly see some information is transmitted.

Do I need to use the INTB0 pin just as a sensing pin and two other pins for TX and RX.

Hope somebody can help me out.

Thanks, regards Jordy

Hi jordy
can you attach your flowcode and point to where your problem is as this will make it easier for people too help

Yes sorry,

I will attach my program this afternoon.
Hope this will help you guys more,

Thanks in advance.

Regards Jordy

Here is the attached program