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by amk
Wed Oct 28, 2015 9:34 pm
Forum: Compute Module
Topic: CE compliant information
Replies: 17
Views: 5766

Re: CE compliant information

If one of the directives a particular product needs to obey includes fire safety or food safety then it is perfectly possible that sort of information might be needed... Yes that might be so but TS specifically requests: "we would need information about the construction of the PCB’s compute module:...
by amk
Wed Oct 28, 2015 3:38 pm
Forum: Compute Module
Topic: CE compliant information
Replies: 17
Views: 5766

Re: CE compliant information

I still don´t understand why TS requires this information for CE certification. It´s all ELV stuff, no dangerous high voltage or high power here. V0 is a UL classification, totally not relevant for EU.
by amk
Thu Oct 15, 2015 2:04 pm
Forum: Compute Module
Topic: CE compliant information
Replies: 17
Views: 5766

Re: CE compliant information

Thank you for the reply. The links do not refer specifically to the compute module. Do you have any documents or information about the construction of the PCB’s compute module? Thank you in advance Certified to FCC class B as it is expected to be integrated into domestic applications http://www.ele...
by amk
Thu Oct 15, 2015 1:54 pm
Forum: Compute Module
Topic: CE compliant information
Replies: 17
Views: 5766

Re: CE compliant information

We used the compute module on our product and we have to certify the product CE. To do this, we would need information about the construction of the PCB’s compute module: the class of flammability, clearance, creepage distances, electrical insulation. Could you send us these information? Thank you....
by amk
Sun Aug 16, 2015 9:32 pm
Forum: Compute Module
Topic: No HDMI on custom board, but fine on OEM dev board.
Replies: 14
Views: 2757

Re: No HDMI on custom board, but fine on OEM dev board.

I'm not familiar with Kicad so I can't give you any support on it's use. To calculate the right trace width and trace seperation you also need to know the height above the conducting plane and the diëlectric constant of the board material. The Saturn PCB design toolkit offers a nice free calculator ...
by amk
Sun Aug 16, 2015 10:37 am
Forum: Compute Module
Topic: No HDMI on custom board, but fine on OEM dev board.
Replies: 14
Views: 2757

Re: No HDMI on custom board, but fine on OEM dev board.

I noticed the TPDS12016 has some low power settings, disabling the load switch and I2C/CEC level translators. You might want to have those enabled all the time. I have successfully used a TPD12S521 without any problems at all. Other problems to be aware of is the signal integrity of the HDMI signals...
by amk
Tue Aug 11, 2015 12:11 pm
Forum: Compute Module
Topic: Edge contact quality issue
Replies: 2
Views: 794

Re: Edge contact quality issue

http://i.imgur.com/ZRlSeNH.jpg In the above picture you can see the protrusions that are curling into a burr, they are really sharp and caused damage to the contact fingers in the SODIMM socket. http://i.imgur.com/BgOPrJz.jpg The burrs stick outside the board, not a lot but enought to cause problem...
by amk
Tue Aug 11, 2015 9:56 am
Forum: Compute Module
Topic: Edge contact quality issue
Replies: 2
Views: 794

Edge contact quality issue

Today I tried to install a CM into a Molex 1473149-4 socket and noticed that even after using quit a lot of force it wouldn't slide in the socket. I noticed before that CM's required some force to slide in the socket but in this case it wouldn't fit at all. The problem seems to be caused by burrs at...
by amk
Thu Apr 16, 2015 6:20 am
Forum: Compute Module
Topic: Multi Server CM Board
Replies: 22
Views: 3849

Re: Multi Server CM Board

Why use a two layer board? This sort of circuitry requires good signal integrity for the high speed signals and a low impedance (low for high frequency) power distribution network. Such a board will probably radiate to much and be too susceptible for exteranal noise sources. I would at least use a 4...
by amk
Tue Apr 14, 2015 9:30 pm
Forum: Compute Module
Topic: CM and LAN9514
Replies: 28
Views: 14008

Re: CM and LAN9514

In that case I will do a measurement to assure the correct timing requirements are met.
I'm thankfull for the usefull comments and contributions, helps to get stuff working :D
by amk
Tue Apr 14, 2015 1:44 pm
Forum: Compute Module
Topic: CM and LAN9514
Replies: 28
Views: 14008

Re: CM and LAN9514

Got it working, besides the pin definitions you also have to add the clock configuration code to the .dts file.

Can someone comment on the use of the LAN reset signal? Without the use of this signal the LAN9514 also seem to work fine.
by amk
Tue Apr 14, 2015 7:06 am
Forum: Compute Module
Topic: CM and LAN9514
Replies: 28
Views: 14008

Re: CM and LAN9514

I have got my hardware up and running, using a separate clock crystal for the LAN9514. However I noticed the RPI model B+ uses the SoC to generate this signal. To save on BOM cost I would like to use this option as well. The problem however is there is no 25MHz clock signal on GPIO44. What should I ...
by amk
Sat Feb 28, 2015 12:40 pm
Forum: Compute Module
Topic: Optimal VBAT and internal SMPS efficiency
Replies: 7
Views: 1779

Re: Optimal VBAT and internal SMPS efficiency

I checked and model B+ also has VBAT connected to 5V. Only the compute module kit has a VBAT of 3.3V.
by amk
Tue Feb 24, 2015 4:08 pm
Forum: Compute Module
Topic: Optimal VBAT and internal SMPS efficiency
Replies: 7
Views: 1779

Re: Optimal VBAT and internal SMPS efficiency

I have decided that I will supply VBAT with 3.3V, since this will lower the stress on the SoC step down regulator. In my design I have higher rail voltages available so I will spend some more money on a very efficient 12V to 3.3V step down regulator. Simulation results look good and give me an overa...
by amk
Tue Feb 24, 2015 3:13 pm
Forum: Compute Module
Topic: Optimal VBAT and internal SMPS efficiency
Replies: 7
Views: 1779

Re: Optimal VBAT and internal SMPS efficiency

I agree it will depend much on the load situation, so due to the lack of available data I have to make some measurements. Normally stepping down with a larger ratio gives greater losses due to higher quiescent current and the lower duty cycle. In a synchronous rectification design like this that cou...
by amk
Tue Feb 24, 2015 2:26 pm
Forum: Compute Module
Topic: Optimal VBAT and internal SMPS efficiency
Replies: 7
Views: 1779

Re: Optimal VBAT and internal SMPS efficiency

Thank you for fast reply :) Stepping down from 5V to 1.2V at 80% sounds pretty good to me. If this number is correct stepping down from 3.3V to 1.2V should be in the range of at least 90% to match the same performance if I first have to step down from 5V to 3.3V at 90% efficiency (0.9x0.9 vs. 0.8). ...
by amk
Tue Feb 24, 2015 2:03 pm
Forum: Compute Module
Topic: Optimal VBAT and internal SMPS efficiency
Replies: 7
Views: 1779

Optimal VBAT and internal SMPS efficiency

Can any of the engineers comment on the efficiency of the internal buck regulator for the CPU core voltage? The design note states that the best efficiency is in the input range of 3.3 ~ 4.3V. Hooking VBAT to 3.3V would make sense if this was the only voltage available. But what is I also have 5V av...
by amk
Tue Feb 24, 2015 1:43 pm
Forum: Compute Module
Topic: CM and LAN9514
Replies: 28
Views: 14008

Re: CM and LAN9514

Nice topic, doing the same over here, will combine the LAN9514 with PoE for powering my application.
by amk
Tue Feb 24, 2015 1:39 pm
Forum: Compute Module
Topic: BOM for Compute IO board?
Replies: 12
Views: 2945

Re: BOM for Compute IO board?

I think most information can be copied from the available circuit diagram of the original B version (non plus). The original B version had a LAN9512 attached but I guess hooking up a LAN9514 would not take much more effort. There is another topic on the forum dealing with that, clocking the LAN9514 ...

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