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by dp11
Tue Nov 23, 2021 5:42 am
Forum: Compute Module
Topic: CM4 with USB Hub Errors
Replies: 1
Views: 88

Re: CM4 with USB Hub Errors

Why the non 'B' version of the 2514? Can you share your schematics and pcb layout. The fact it does not go into high speed mode might well suggest a hardware problem?
by dp11
Mon Nov 22, 2021 2:02 pm
Forum: Compute Module
Topic: Cannot boot and flashing Compute Module 4 IO Board
Replies: 4
Views: 201

Re: Cannot boot and flashing Compute Module 4 IO Board

I can't see how from boot all the LEDs can be lit. . Did any of the PSU rails accidentally get shorted ?
by dp11
Sun Nov 21, 2021 7:58 am
Forum: Compute Module
Topic: Keep loosing 2.4GHz after updates on Bullseye
Replies: 9
Views: 344

Re: Keep loosing 2.4GHz after updates on Bullseye

UnH0LY1 wrote:
Sat Nov 20, 2021 10:05 pm
Well, just came home and out of curiosity plugged in my ALFA usb wifi adapter and it works fine. It is plugged in with a foot long usb cable and connected right away to my 2.4GHz network side. So i guess it is not usb interference???
Is your alfa usb wifi adapter usb 3? I suspect not.
by dp11
Sat Nov 20, 2021 8:35 am
Forum: Compute Module
Topic: Kernel Panic error during boot when VL805 =1
Replies: 10
Views: 342

Re: Kernel Panic error during boot when VL805 =1

Can you post your schematics and pcb layout? I am waiting on a decision to be made regarding sharing the PCB layout and the schematic since these are deemed confidential. While I'm waiting on the decision, is there a proper channel to share confidential information on the forum? You may contact one...
by dp11
Fri Nov 19, 2021 10:02 pm
Forum: Compute Module
Topic: Kernel Panic error during boot when VL805 =1
Replies: 10
Views: 342

Re: Kernel Panic error during boot when VL805 =1

Can you post your schematics and pcb layout?
by dp11
Wed Nov 17, 2021 9:22 pm
Forum: Troubleshooting
Topic: Pi CM4 not booting from SD
Replies: 1
Views: 56

Re: Pi CM4 not booting from SD

If you have an eMMC CM4 then you can't boot or use an SDCARD. You will need to program your CM4 via USB link if your carrier board supports it.
by dp11
Wed Nov 17, 2021 2:47 pm
Forum: HATs and other add-ons
Topic: LEGO Build Hat issue
Replies: 5
Views: 222

Re: LEGO Build Hat issue

The Bullseye warning has been fixed and will be in the next stable release. As it is a warning you can ignore it.
by dp11
Wed Nov 17, 2021 11:24 am
Forum: Compute Module
Topic: CM4 CPU models have different power LED control changes
Replies: 4
Views: 170

Re: CM4 CPU models have different power LED control changes

Can you post the schematics of your base board ?
by dp11
Mon Nov 15, 2021 10:10 pm
Forum: HATs and other add-ons
Topic: LEGO Build Hat issue
Replies: 5
Views: 222

Re: LEGO Build Hat issue

Could you try downloading the Buildhat software again from the website. An issue has been fixed.
by dp11
Mon Nov 15, 2021 5:43 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4 not booting - SDRAM Failure
Replies: 49
Views: 2470

Re: Raspberry Pi 4 not booting - SDRAM Failure

Blinking Red LED is likely to mean either the external PSU has failed or it is overloaded. Try first of all removing everything connected to the PI and seeing if the Red LED remains lit.
by dp11
Sat Nov 13, 2021 8:41 pm
Forum: Compute Module
Topic: Is my CM4 done?
Replies: 9
Views: 340

Re: Is my CM4 done?

What did you do to make it boot ?. It might be worth reading around on the forum about Bullseye.
by dp11
Sat Nov 13, 2021 7:26 pm
Forum: Compute Module
Topic: Custom CM4 carrier board stuck in bootloop
Replies: 6
Views: 207

Re: Custom CM4 carrier board stuck in bootloop

I assume there is noting in the M2 socket. I can't obviously see anything wrong.
by dp11
Sat Nov 13, 2021 6:20 pm
Forum: Compute Module
Topic: Is my CM4 done?
Replies: 9
Views: 340

Re: Is my CM4 done?

I would contact Waveshare.
by dp11
Sat Nov 13, 2021 6:19 pm
Forum: Compute Module
Topic: Custom CM4 carrier board stuck in bootloop
Replies: 6
Views: 207

Re: Custom CM4 carrier board stuck in bootloop

Can we see the fully schematics ? are you sure you have a good enough +5v supply ?
by dp11
Sat Nov 13, 2021 7:00 am
Forum: Compute Module
Topic: Is my CM4 done?
Replies: 9
Views: 340

Re: Is my CM4 done?

Which io board do you have?
by dp11
Fri Nov 12, 2021 5:22 pm
Forum: Compute Module
Topic: Custom CM4 carrier board not powering up
Replies: 10
Views: 353

Re: Custom CM4 carrier board not powering up

I can't obviously see anything wrong. I wonder if you +5v supply is dropping out as the CM4 is powering up ?
by dp11
Fri Nov 12, 2021 4:05 am
Forum: Compute Module
Topic: Custom CM4 carrier board not powering up
Replies: 10
Views: 353

Re: Custom CM4 carrier board not powering up

Can you you share your pcb layout?
by dp11
Thu Nov 11, 2021 10:13 pm
Forum: Compute Module
Topic: Custom CM4 carrier board not powering up
Replies: 10
Views: 353

Re: Custom CM4 carrier board not powering up

I would check carefully for shorts .
by dp11
Thu Nov 11, 2021 7:18 pm
Forum: Compute Module
Topic: Custom CM4 carrier board not powering up
Replies: 10
Views: 353

Re: Custom CM4 carrier board not powering up

Are both R5 and R6 fitted ?
by dp11
Thu Nov 11, 2021 4:58 am
Forum: Compute Module
Topic: Custom CM4 carrier board not powering up
Replies: 10
Views: 353

Re: Custom CM4 carrier board not powering up

Most likely is that you are either overloading the 3.3v rail or back feeding some power into the CM4 via some other pins e.g. The ethernet led pins. Can you post your schematics?
by dp11
Tue Nov 09, 2021 8:22 pm
Forum: Compute Module
Topic: Replace PWR LED buffer (74LVC1G07SE-7) with PNP?
Replies: 4
Views: 653

Re: Replace PWR LED buffer (74LVC1G07SE-7) with PNP?

The green led output is from an internal FET. The pwr led output is a low current logic output and so needs buffering.
by dp11
Mon Nov 08, 2021 9:08 am
Forum: Compute Module
Topic: CM4 Ethernet Not working
Replies: 9
Views: 941

Re: CM4 Ethernet Not working

See first post.
by dp11
Fri Oct 29, 2021 9:06 am
Forum: Compute Module
Topic: Custom PCB Bluetooth Issue
Replies: 25
Views: 717

Re: Custom PCB Bluetooth Issue

This probably isn't the problem but ideally the +5v to the CM4 should come from C10 and not L1. If you are worried about EMC the aim of the input capacitors is to form a low inductance path between the input caps and the switch mode PSU. C2 ,C4,C6 current will all likely flow in via by R4. Having th...
by dp11
Thu Oct 28, 2021 12:54 pm
Forum: SDK
Topic: How many adc_read()s maximally in 1 second?
Replies: 6
Views: 387

Re: How many adc_read()s maximally in 1 second?

For frequency domain measurements, you can actually use the ADC to subsample 250Khz of bandwidth up to about 30MHz (after which the analogue pads parallel-bonded digital pads and input mux start to attenuate the input). You just have to be careful to pick one of the positive frequency images not ne...

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