Possible bug GPS module

[petesmart]

Hi MM team,

I am working with the GPS module attached to the MIAC system. The unit functions well as a GPS, and I am able to get all GPS data back to the display without any issue.

I am testing out the SD card function on the GPS module using an example supplied with the MAIC system examples (FC 5) file name 'demo_GPS_fat'. The problem is that the SD card will not initialise, basically the code sits in a loop until it times out with a 254 "no response".

To prove that it is not an SD card issue I used an ECIO module and an EB 037 to verify that I can initialise, read and write from the SD card. The card that I'm using for the test is made by SanDisk and it's a 2 GB module. I used one of the other examples that you have for FC 5 and could read the file names from the directory onto an LCD without any issue.

Back to the MIAC system and the GPS module, I created a very simple to command sequence which initiated the GPS module followed by the FAT initialisation. I connected the can analyser and observed that it was stuck in the loop with commands 360, 361, 362, which are the SPI 2 command sequence for the GPS module. Whilst the software made many attempts to initialise the card, It appears as though the card is not responding.

I have attached a capture of the can bus sequence beginning with the initialisation using command 132, which is a software reset to the GPS module. Note GPS module uses ID 60.

I would appreciate if you could take a look at this for me to verify if it's a card issue it's possibly a bug with the SD functionality on the GPS module.

Let me know if you need any additional information.

All the best,

Pete

[JohnCrow]

Hi Pete
Benj sent me an updated component for the MIAC SD card component.
I was having problems with that, even after updating the component for the e-block.

http://www.matrixmultimedia.com/mmforum ... c&start=25
Its working fine on my system with both the GPS and the Serial modules.

[petesmart]

Brilliant, many thanks John.

Will give it a try and come back to you....

All the best

Pete

[petesmart]

Thanks John for pointing me in the right direction on this one – mental note to self, should do a little more thorough search of the forum before put my hand up . I did actually read the tail end of that thread some time ago and did not look into it any further, there is quite a lot of good info there.

The rig lab testing at the moment is a MIAC with an advanced expansion and a GPS expansion module on the same bus. Whilst it is early days of the testing, I have to say apart from the minor SD card issues it all functions extremely well.

For interest, I have included the can bus capture in the form of a.CSV file which shows the initiation sequence/communication on the can bus. It's interesting to note that the whole process takes around 730 mSec and there is quite a lot of data going backwards and forwards on the bus – this one is for the MM team, is this a normal amount of traffic for this simple task?

I can also confirm that the MIAC system GPS_FAT example now works and is a good example for people starting with the advanced modules on how to configure up the system.

Thanks again to your help.

All the best.

Pete

[LeighM]

Thanks John and Pete for your work and experiences with this.

The FAT component has been developed quite extensively recently.
In view of that on-going improvement (and to comply with a larger range of cards) we took the decision to drive the MIAC expansion module with a low level interface, rather than take a snapshot of the component code and commit it to firmware. As you notice that results in a lot of CAN traffic, but does gives us more flexibility.

We will continue to look at this and welcome your feedback.

Best regards,
Leigh

[petesmart]

Thanks Leigh,

aaaahh...what you say makes sense, particularly with the high degree of variability across the range of cards. It was good to confirm that its operating as expected. The 700 msec init time is not going to be an issue I believe in most industrial applications as this call is generally made at the start of the operation and not revisited until the card is changed.

I had a play with your greenhouse controller example for the Miac system. It's great! Added it to the bottom of this post for interest of other forum members as it contains functionality across all 3 modules.

Keep up the good work.

All the best,

Pete