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Re: Red LED on AQ with DIMU and new firmware

PostPosted: Wed Apr 30, 2014 1:33 am
by rput
Thanks for posting that Farooq. I will look at it tomorrow and see if it solves the issue on my board as well.
Richard

Re: Red LED on AQ with DIMU and new firmware

PostPosted: Thu May 01, 2014 8:07 pm
by poirierp
I have done some research here and found some very interesting results. There does appear to be some bad solder joints that are definitely causing the occasional issue. However, I am still getting units that seem to work randomly and stop randomly. I have noticed that on start-up the communication to the DIMU is SPI running at roughly 650KHz. Then very quickly afterwards the clock rate jumps to over 10MHz which then doesn't always result in data being sent back from the DIMU. I managed to read the part number of the IMU chipset and get its datasheet and was able to determine that the maximum recommended operating clock rate for SPI is only 1MHz which is 10 times less than what it appears to be operating at!!! Could this be the source of a lot of issues for those that have more knowledge of the design?

Re: Red LED on AQ with DIMU and new firmware

PostPosted: Thu May 01, 2014 8:16 pm
by bn999
Which chip are you talking about? The SPI clock frequency is manipulated to stay well within each chips' capabilities. Also note that those capabilities depend on which registers are being accessed for some chips.

Re: Red LED on AQ with DIMU and new firmware

PostPosted: Thu May 01, 2014 9:11 pm
by poirierp
I am referring to the DIMU U5 which if I read correctly is a InvenSense MPU-6000 which as per the data sheet I was able to get has a maximum SPI clock rate of 1MHz. If I probed correctly the SPI clock going to it through pin J1:15 is 659KHz on boot-up and typically switches to just over 10MHz after a second or so as measured using an oscilloscope while the system booted up (snapshots attached).

I don't know the full system very well so I cannot definitively confirm that this is correct or not but to me it seems suspicious that I am typically seeing a 10MHz clock after the initial power-up sequence most of the time (but not 100% of the time). Even on systems I do have working the clock rate appears to be working at this higher clock rate consistently and not at the much lower rate of 1MHz. If required I can grab more screen shots but it will have to wait till tomorrow.

Re: Red LED on AQ with DIMU and new firmware

PostPosted: Thu May 01, 2014 9:33 pm
by poirierp
Note that I understand different SPI devices can be addressed with different clock rates. However, when it does go into this 10MHz mode the only clock rate I see going to the DIMU is the 10MHz clock.

Re: Red LED on AQ with DIMU and new firmware

PostPosted: Thu May 01, 2014 9:42 pm
by bn999
Take a closer look at the datasheet. The MPU6K is being run within its specified SPI frequency.

Re: Red LED on AQ with DIMU and new firmware

PostPosted: Mon May 05, 2014 6:44 pm
by poirierp
Hello,

You are correct I found the section in question. I have to say its not the worst datasheet I have ever seen but it is far from being the best as the tables clearly indicate the maximum clock rate is 1MHz and only indicates otherwise buried in some text in another section of the datasheet. My apologize.

It still however does leave the fact that we appear to have intermittent communication during start-up in some setups for unknown reasons. When it works great it works but some combination of boards randomly seem not to work. Any suggestions people may have in what the cause may be and how to solve it would be greatly appreciated.

Re: Red LED on AQ with DIMU and new firmware

PostPosted: Wed May 14, 2014 1:04 am
by SuperSharpShooter
Looks like my DIMU issue has the same symptoms as this one. I'll try swapping my working DIMU in from the other board and see if it will boot on the board which stopped booting...

Edit: flashed R386 and it works again.

Re: Red LED on AQ with DIMU and new firmware

PostPosted: Tue Nov 04, 2014 11:44 pm
by johannes3154
Hey Guys,
i ran into the same issue, i bought a AQ6 with DIMU and tried to install a Dimu Firmware, with no success. No matter which version i try, it constantly gives me the red light.
When i flash an old firmware or a non Dimu version everything works like a charm. The soldering of the Dimu is fine.
How did you get rid of that problem?
Cheers
Johannes

Re: Red LED on AQ with DIMU and new firmware

PostPosted: Wed Nov 05, 2014 5:08 pm
by chschmid
The latest Firmware uses the left red LED to display radio connection. Is it that you are asking?