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by MichaR
Thu Mar 09, 2017 7:46 am
Forum: HATs and other add-ons
Topic: LVDS add-on for Raspberry models with 40pin GPIO
Replies: 68
Views: 50686

Re: LVDS add-on for Raspberry models with 40pin GPIO

Hi, 4-layers, right? Looking forward to see it in a video! yes, 4 layers (top: signal, L2: ground, L3: power, bottom: signal). I will make video later, if I have a full soldered PCB (the audio amplifier is not available at the moment at mouser nor other distributors). I'm working on something simila...
by MichaR
Thu Mar 09, 2017 5:59 am
Forum: HATs and other add-ons
Topic: LVDS add-on for Raspberry models with 40pin GPIO
Replies: 68
Views: 50686

Re: LVDS add-on for Raspberry models with 40pin GPIO

OK, it's late, but I got my PCB's and soldered one partly... Just a 10x8 cm board for CM1, CM3 and CM3L with the typical ethernet/USB interface, included audio amplifier (not soldered yet), the DS90C387 as DPI to LVDS-converter, backlight controller for smaller displays... all powered by a 12V PSU :...
by MichaR
Mon Mar 06, 2017 6:05 am
Forum: Compute Module
Topic: costum CM expander board
Replies: 2
Views: 771

Re: costum CM expander board

Hm, you are sure PoE is working in that way you designed it? I'm really unsure... - There is no PD-controller to initiate the power on the PoE-switch side. The source has to know, which PoE-Class your PD needs and so on. So you may have power or not - depending on the used switch. - Both DC-DC-conve...
by MichaR
Mon Feb 27, 2017 12:17 pm
Forum: Compute Module
Topic: CM3 always crashes within minutes under load
Replies: 39
Views: 5500

Re: CM3 always crashes within minutes under load

Tested with Raspbian, OpenElec and PiLFS. Only modification is that the 24 bit DPI-Interface is enabled and configured. Btw. I think, the core temperature is higher than the 55°. On my two modules the CPU has an outer temperature of more than 40°C. So the core temp. is at least 65°C or even more. be...
by MichaR
Mon Feb 27, 2017 5:10 am
Forum: Compute Module
Topic: CM3 always crashes within minutes under load
Replies: 39
Views: 5500

Re: CM3 always crashes within minutes under load

Morning,

I have the same problem with the two CM3L I own. A small heatsink on top of the CPU solves the problem for me.

best regards
Micha
by MichaR
Mon Feb 20, 2017 5:33 am
Forum: Compute Module
Topic: Potential HDMI licensing issue with compute module?
Replies: 26
Views: 6360

Re: Potential HDMI licensing issue with compute module?

I2C is also a part of DVI-D. Only CEC is missing on DVI-D. But that is no licensing issue. As long as the carrier-board provides no HDMI-connector , there is no licensing issue. In the case of a DVI-connector or just internal connections, that are just a buch of differential signal wires. There is n...
by MichaR
Mon Feb 13, 2017 5:24 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C address 0x78
Replies: 6
Views: 2532

Re: I2C address 0x78

they'd forget to "remove" the Read/Write bit that's the problem when software only people think they understand hardware. The read/write bit is part of the I2C-address... since decades - longer before Linux becomes alive. So the datasheet is correct, but Linux is handling it worng. But anyway, shif...
by MichaR
Fri Dec 30, 2016 5:59 am
Forum: HATs and other add-ons
Topic: LVDS add-on for Raspberry models with 40pin GPIO
Replies: 68
Views: 50686

Re: LVDS add-on for Raspberry models with 40pin GPIO

Hi,

ok I did the test with the DS90C387... works fine for single pixel mode 8-) Have to look for a display with dual pixel interface to test the single to dual pixel conversion mode. Pictures of the board will follow later. The schematic is attached below.

Micha
by MichaR
Fri Dec 09, 2016 12:06 pm
Forum: HATs and other add-ons
Topic: LVDS add-on for Raspberry models with 40pin GPIO
Replies: 68
Views: 50686

Re: LVDS add-on for Raspberry models with 40pin GPIO

The DS90C387 can also single pixel in to dual pixel out conversion. There is a pin to configure that option (single in/single out, single in/dual out and dual in/dual out). Using an ready solution is not the solution I need. My designs are all based on the compute module done on Eurocard size PCB's ...
by MichaR
Fri Dec 09, 2016 6:49 am
Forum: HATs and other add-ons
Topic: LVDS add-on for Raspberry models with 40pin GPIO
Replies: 68
Views: 50686

Re: LVDS add-on for Raspberry models with 40pin GPIO

Ah OK, sounds logical to mee. Sure, price is not so importent... also for me as a hobbyist.

Btw.: Do you have any experience with the DS90C387 as LVDS converter?

best regards
Micha
by MichaR
Fri Dec 09, 2016 5:44 am
Forum: HATs and other add-ons
Topic: LVDS add-on for Raspberry models with 40pin GPIO
Replies: 68
Views: 50686

Re: LVDS add-on for Raspberry models with 40pin GPIO

MichaR wrote: But anyway, with only two layers the PCB most time will fail in any radiation test, even if there is only a small part used for digital applications. As suggested by aBUGSworstnightmare, a 4-layer design, where one inner layer is used for ground and the second inner layer is used for ...
by MichaR
Wed Dec 07, 2016 7:00 am
Forum: HATs and other add-ons
Topic: LVDS add-on for Raspberry models with 40pin GPIO
Replies: 68
Views: 50686

Re: LVDS add-on for Raspberry models with 40pin GPIO

>> The final PCB from the factory probably will have every signal pair shorten. Why do you think this ? Well, if I remember right, the LVDS converter has a pad width of nearly 12 mil. So I think, your traces have a width of around 10 mil. The distance between the traces of one pair is between 6 and...
by MichaR
Tue Dec 06, 2016 5:53 am
Forum: HATs and other add-ons
Topic: LVDS add-on for Raspberry models with 40pin GPIO
Replies: 68
Views: 50686

Re: LVDS add-on for Raspberry models with 40pin GPIO

Sorry Peter, but you design is all other than the best... Your desingn does not match the required impendance for LVDS. Your design have nearly 90° corners. Only the pairs of each signal are length matched and not all traces together as requested for LVDS. The max. frequencies for each trace in the ...
by MichaR
Thu Mar 31, 2016 4:22 am
Forum: Compute Module
Topic: Compute module boot time
Replies: 20
Views: 3786

Re: Compute module boot time

Hi,

did you try to connect the RUN pin directly to 3.3V ? For me that fixed the boot delay. It's strange, but I had to connect it without any pull-up resistor. Even more strange is, that the RUN pin has 3.3V if you left it unconnected, but the CM has a big boot delay.

Micha
by MichaR
Wed Mar 30, 2016 4:47 am
Forum: Compute Module
Topic: Diagnosing problems with LAN9514 and Ethernet Jack
Replies: 8
Views: 4523

Re: Diagnosing problems with LAN9514 and Ethernet Jack

Hi, the XTAL I use is a ceramic SMD type: http://www.reichelt.de/Crystals-SMD-Ceramic-Case/25-000000-MJ/3/index.html?ACTION=3&GROUPID=4003&ARTICLE=85011&OFFSET=500&LANGUAGE=EN That one seems to be out of specs a little bit (only drives 100uW), but works fine on several boards. If you soldered the ch...
by MichaR
Tue Mar 29, 2016 5:29 pm
Forum: Compute Module
Topic: Diagnosing problems with LAN9514 and Ethernet Jack
Replies: 8
Views: 4523

Re: Diagnosing problems with LAN9514 and Ethernet Jack

Hi, I also did it with the reference schematic for the LAN9514 and it works without any problems. The difference I can see between your schematic and the reference is, that you did not connect the JTAG-Pins except TDO to VDD and on of the Test-Pins is not connected. Atached is my schematic I use. Do...

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