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by John Westlake
Mon Jun 24, 2019 11:30 pm
Forum: Compute Module
Topic: compute moduel upgrade (rpi4)
Replies: 2
Views: 143

Re: compute moduel upgrade (rpi4)

Beat me to the post :) With the launch of the new RPi4B I guess it can only be expected that "we" here on the CM section of the forum would be asking for for a CM4 :) I'm sure the issue faced by RPi is wither or not to move away from the CM1/CM3 Compatible pin arrangement - and I personally I believ...
by John Westlake
Sat Jun 15, 2019 5:08 pm
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1085

Re: USB 2.0 Dropped frames

jdb, Thank you for your help with this issue. After speaking with my software guys I now have a better understanding of the "work around" your proposing - whats the number of USB devices you consider limiting the USB Host Bus to? (We need to consider that USB Hubs need to be factored as USB devices)...
by John Westlake
Fri Jun 14, 2019 2:23 am
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1085

Re: USB 2.0 Dropped frames

jdb,

Thank you for your reply, being a hardware guy the the in's and out of the USB protocol is way beyond me :) but I've forward your post to the software guys and see what they make of it :)
by John Westlake
Wed Jun 12, 2019 2:22 pm
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1085

Re: USB 2.0 Dropped frames

WRT I2S we need to support HiRes AUdio and DSD with the DAC being clock Master (so the Audio Data from the RPI is clocked out by the audio device) - otherwise the RPI generated master clock phase nosie is way too high for performance applications. 1. I'm not sure how we can make the I2S a slave (DAC...
by John Westlake
Tue Jun 11, 2019 2:37 pm
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1085

Re: USB 2.0 Dropped frames

I'm not sure how much control we have as XMOS as pretty much locked down the USB code on there devices (After the PHY, the USB "interface" is handled by software code in the XMOS hence some very funky programming was required to make it work at USB2.0 speeds). While the XMOS experiences dropouts oth...
by John Westlake
Tue Jun 11, 2019 10:51 am
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1085

Re: USB 2.0 Dropped frames

jdb wrote:
Fri May 17, 2019 9:18 am
Please post
- the full output of dmesg after playback has started and you've had at least one corrupt audio frame
- the output of lsusb -v and lsusb -t
jdb,

Anything interesting from the message dumps you requested?
by John Westlake
Thu May 23, 2019 1:02 am
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1085

Re: USB 2.0 Dropped frames

OK, noted, will do.
by John Westlake
Thu May 02, 2019 1:52 pm
Forum: Compute Module
Topic: CM3+ with 7" display on DSI0
Replies: 20
Views: 4583

Re: CM3+ with 7" display on DSI0

Great you can move forward now - this is always the hardest stage of development when your not sure if your battling a hardware or software issue!
by John Westlake
Thu May 02, 2019 10:18 am
Forum: Compute Module
Topic: CM3+ with 7" display on DSI0
Replies: 20
Views: 4583

Re: CM3+ with 7" display on DSI0

Might be a silly question, your not missing I2C pull-up resistors or some such on your PCB are you by anychance?

(I'm not sure if the panel has them on its interface PCB or not - but just wondering if you have a hardware issue that's causing you to chase your tail...
by John Westlake
Tue Apr 30, 2019 3:54 pm
Forum: Compute Module
Topic: USB 2.0 Dropped frames
Replies: 14
Views: 1085

USB 2.0 Dropped frames

I have designed a range of audio streamers based on the CM3 - with more designs in the pipework. The streamers interface to the external Audio DAC via USB 2.0, however under certain conditions we experience random audible popping and clicks which are very hard to diagnose. It would seem that some US...
by John Westlake
Mon Mar 11, 2019 7:05 am
Forum: Compute Module
Topic: CM3 eMMC override?
Replies: 2
Views: 374

Re: CM3 eMMC override?

I dont believe so as the datelines to the external CM3 are not physically connected on CM3 modules with onbaord eMMC - instead they are routed via resistor jumpers to the onboard eMMC memory IC.
by John Westlake
Sun Jan 27, 2019 7:23 am
Forum: Compute Module
Topic: CM3 on 2 layer PCB
Replies: 5
Views: 978

Re: CM3 on 2 layer PCB

Hi Javier, Its really a question about your PCB design skills and a bit of luck... If you can run the USB lines and camera port without other tracks crossing them (so solid Ground Plane below and surrounding the differential USB and Camera Port tracks then you should be OK. Its really a question of ...
by John Westlake
Fri Dec 28, 2018 8:39 am
Forum: Compute Module
Topic: About the jtag
Replies: 2
Views: 682

Re: About the jtag

OK a wild guess here, but the way I understand the CM3 SoC design is that basically 90% of the chip die is the GPU (the Video core - VC_JTAG) with quad ARM processors "hung off the side" - ARM_ JTAG. Presuming this genesis is correct then I can imagine that the JTAG's have been kept separated betwee...
by John Westlake
Wed Oct 31, 2018 10:58 pm
Forum: Compute Module
Topic: Expandable baseboard (slot system) for CM3
Replies: 28
Views: 12852

Re: Expandable baseboard (slot system) for CM3

That's brilliant news that someone is working with the dual framebuffer beta testing - sadly software is well beyond my skills. Will your board be available for sale? I'm really keen on adding a display panel on the DPI port for the products "Front Panel" interface / user controls and still have HDM...
by John Westlake
Wed Oct 31, 2018 9:39 pm
Forum: Compute Module
Topic: Expandable baseboard (slot system) for CM3
Replies: 28
Views: 12852

Re: Expandable baseboard (slot system) for CM3

Very nice work :) Are you running two independent displays (two frame buffers) on a single CM3? - if so how are they interfaced?

Again, nice to see such professional design work :)
by John Westlake
Tue Oct 09, 2018 4:48 pm
Forum: Compute Module
Topic: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board
Replies: 14
Views: 2432

Re: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board

Sorry, I don't work for raspberry pi so cannot publish a raspberry pi reference design (I'm a retired Engineer). I've looked at your PCB design and it does not look too badly designed at all (from what I can tell from PDF overlays) - I'm struggling to understand what the issue could be - I really ne...
by John Westlake
Mon Oct 08, 2018 10:35 am
Forum: Compute Module
Topic: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board
Replies: 14
Views: 2432

Re: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board

Very odd - have you tried with the ESD protection removed? I have full tools here in my lab to diagnose USB issue (including TDR) - if you want I'd be happy to diagnose your PCB if you can send one to me (with just the USB section built ok) - I'm located in the Czech Rep. I'm pretty sure I'd be able...
by John Westlake
Sun Oct 07, 2018 11:41 am
Forum: Compute Module
Topic: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board
Replies: 14
Views: 2432

Re: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board

I cannot open your PCB layouts - can you post them as PDF files? Also, I'm not sure if its normal to see USB OTG messages (Maybe it IS normal), but a thought occurs to me - have you tied the CM3 USB OTGID pin to ground (CM3 Pin 168)? Pin 168 should be grounded. "The BCM283x USB port is On-The-Go (OT...
by John Westlake
Thu Oct 04, 2018 4:35 pm
Forum: Compute Module
Topic: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board
Replies: 14
Views: 2432

Re: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board

@John Westlake: Sir we have tried adding up pull-up on the PRTCTL2 pin but there is no change , the bug is not resolved. Can you show us your PCB layout? Might be worth confirming your 25MHz Clock frequency, 33pf seems like a large crystal loading (depends on the crystal Spec) - if you don't have a...
by John Westlake
Mon Oct 01, 2018 9:40 pm
Forum: Compute Module
Topic: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board
Replies: 14
Views: 2432

Re: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board

Can you show us your PCB layout? Might be worth confirming your 25MHz Clock frequency, 33pf seems like a large crystal loading (depends on the crystal Spec) - if you don't have an accurate Frequency counter then try reducing the Crystal loading caps to say 18pF Best location to measure the clock is ...
by John Westlake
Mon Oct 01, 2018 8:33 pm
Forum: Compute Module
Topic: LAN9514
Replies: 24
Views: 4156

Re: LAN9514

To improve your Ground "decoupling path" you can simply Ground pins 29, 30 & 32 - this gives you a tight direct Ground connection to the two local PSU decoupling capacitors.

We Ground these pins on our designs....
by John Westlake
Sun Sep 30, 2018 6:22 pm
Forum: Compute Module
Topic: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board
Replies: 14
Views: 2432

Re: USB [LAN9514I] Enumeration Issue in Compute Module 3L Custom Carrier Board

I wonder if your issue is related to the Over Current (OC) protection arrangement you've used - I seem to recall that the LAN9514 supports various software defined OC operating modes. You have configured your device with individual Port current protect which is not the default hardware and 'Software...
by John Westlake
Sun Sep 30, 2018 5:28 pm
Forum: Compute Module
Topic: SDIO on CM3
Replies: 3
Views: 1197

Re: SDIO on CM3

Broadcom may have the interface locked to be compatible with only the 4GB eMMC on the CM3, so as to prevent individuals from rolling their own eMMC boot devices. We use a 16GB eMMC with the CM3Lite..... and have used bigger devices on the lab bench - so I can answer that its not "Locked" to 4GB dev...
by John Westlake
Fri Sep 28, 2018 3:57 am
Forum: Compute Module
Topic: LAN9514
Replies: 24
Views: 4156

Re: LAN9514

Apart from the PCB layout need to be take care, does this “undocumented mode of operation” need any software changes to support it? Thanks. I really cannot recommend using the LAN9514 in this way - its undocumented by Microchip for a reason as I went into some length to explain... As others have al...
by John Westlake
Wed Sep 26, 2018 9:55 pm
Forum: Compute Module
Topic: LAN9514
Replies: 24
Views: 4156

Re: LAN9514

The “undocumented mode of operation” is related to reducing the total power consumption and heat dissipation of the LAN9514 – but at the potential expense of performance. Essentially, the LAN9514 internal 3.3V to 1.8V LDO’s that power the USB PLL, LAN PLL circuits and Cores are externally powered fr...

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