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by James Adams
Tue Apr 30, 2019 8:01 am
Forum: Compute Module
Topic: Schematics for the CM3+
Replies: 2
Views: 220

Re: Schematics for the CM3+

Yes the CM3+ is the same as CM3 except using BCM2837B (package with the can) instead of BCM2837A.
by James Adams
Thu Sep 21, 2017 11:39 am
Forum: Compute Module
Topic: CMIO v3 design files
Replies: 6
Views: 2258

Re: CMIO v3 design files

by James Adams
Thu Sep 21, 2017 9:53 am
Forum: Compute Module
Topic: Flickering HDMI on custom CM3 board
Replies: 22
Views: 4237

Re: Flickering HDMI on custom CM3 board

This could also be a power supply noise issue - the HDMI PHY uses both 3V3 and 1V8, so one thing to check is your supplies are clean and sequenced properly (compare them with CMIO3 board).
by James Adams
Wed Sep 13, 2017 8:27 am
Forum: Compute Module
Topic: Boot problem with V3 on card designed past year
Replies: 22
Views: 3967

Re: Boot problem with V3 on card designed past year

When the CM3 does not start can you measure the voltage across C42 on the CM3 (bottom right corner of the module next to L1). I'm finding it hard to explain why it works on a CMIO3 but on a CMIO1 (with VBAT at 5V) it does not - as these boards really are identical except the VBAT power and the CMIO3...
by James Adams
Tue Sep 12, 2017 10:30 am
Forum: Compute Module
Topic: Boot problem with V3 on card designed past year
Replies: 22
Views: 3967

Re: Boot problem with V3 on card designed past year

2 things:

Can you try delaying RUN a bit more before bringing it high?

I'm still concerned about the residual voltage on the supplies - why are they starting at ~500mV?

James
by James Adams
Mon Sep 11, 2017 11:42 am
Forum: Compute Module
Topic: Boot problem with V3 on card designed past year
Replies: 22
Views: 3967

Re: Boot problem with V3 on card designed past year

Can you explain why there are 2 3V3 traces (blue and yellow)? Also can you explain why the traces start at ~500mV (the yellow one then drops down before rising again)? Residual voltages on power rails is a not-uncommon cause of these kind of power-up issues. Some idea of your powerchain architecture...
by James Adams
Mon Sep 11, 2017 8:23 am
Forum: Compute Module
Topic: Boot problem with V3 on card designed past year
Replies: 22
Views: 3967

Re: Boot problem with V3 on card designed past year

With your LED on EMMC_EN_N you are just measuring the forward LED voltage drop (through 10K to 3V3). Seems to be working to me. This feels like a power supply issue, the CM3 takes a lot more current from VBAT. What is the capability of your upstream power supply? (I.e. the 5V input) You need to look...
by James Adams
Mon Sep 04, 2017 2:43 pm
Forum: Compute Module
Topic: 3V3 voltage range
Replies: 1
Views: 773

Re: 3V3 voltage range

Hi Milek7 while we don't guarantee anything outside of 3V3+/- 5% (mostly due to HDMI voltage requirements to meet HDMI certification) I would be surprised if you had any issues running down at 3.0V
by James Adams
Wed Aug 02, 2017 1:24 pm
Forum: Compute Module
Topic: Broken Compute Module
Replies: 5
Views: 1387

Re: Broken Compute Module

Hi themeerd. Are you using the very latest rpiboot software, and what platform are you using to flash with? (PC, Mac, Pi?, which OS?) - are you using a Compute Module IO board and if so which version? What you describe shouldn't be happening, though gsh has fixed a couple of bugs in rpiboot fairly r...
by James Adams
Wed Aug 02, 2017 10:32 am
Forum: Compute Module
Topic: Voltages needed for fast shutdown
Replies: 1
Views: 766

Re: Voltages needed for fast shutdown

Hi JohW. The supply rails need to be up at all times unless you are powering the entire system down - the reason is there are parasitic diodes in the silicon device(s), as is common to most devices with multiple power domains, that can turn on if say the 3V3 domain goes away but the 1V8 stays up (1V...
by James Adams
Thu Jan 26, 2017 9:30 am
Forum: Compute Module
Topic: STICKY: Is CM3 compatbile with the CM1 development board?
Replies: 21
Views: 16342

Re: Is CM3 compatbile with the CM1 development board?

Note that the CMIO-V1 supplies the Compute Module's VBAT from the 3V3, whereas on CMIO-V3 it is supplied from 5V. CM3 can pull significantly more current from VBAT, so if you run heavy CPU loads and/or have anything else using 3V3 it could be marginal. We recommend removing R1 and using a wire to co...
by James Adams
Fri Jan 20, 2017 8:57 am
Forum: Compute Module
Topic: CM3 Board Adapters?
Replies: 12
Views: 2440

Re: CM3 Board Adapters?

Hi Bruce where did you order the kit from, Farnell or RS?
by James Adams
Wed Oct 26, 2016 7:48 am
Forum: Compute Module
Topic: Compute Module Projects
Replies: 3
Views: 4025

Re: Compute Module Projects

Nice job!
by James Adams
Fri Aug 14, 2015 9:24 pm
Forum: Compute Module
Topic: No HDMI on custom board, but fine on OEM dev board.
Replies: 14
Views: 2549

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

GPIO46 should be LOW (indicating HDMI hot plug) so that is likely your problem.

James
by James Adams
Thu Jun 04, 2015 7:40 am
Forum: Compute Module
Topic: unique number
Replies: 25
Views: 3906

Re: unique number

No, the serial number is burned into the OTP during manufacture.
by James Adams
Thu Jun 04, 2015 7:32 am
Forum: Compute Module
Topic: Raspberry Pi Compute Module PCM Audio Output MAX98357
Replies: 10
Views: 6843

Re: Raspberry Pi Compute Module PCM Audio Output MAX98357

The BCM283x I2S driver doesn't natively support mmap which is required for ALSA to do automatic rate/sample conversion. That setup uses the 'mmap_emul' plugin which emulates it (note the emulator is less optimal in terms of performance but mostly fine).
by James Adams
Wed Jun 03, 2015 7:43 am
Forum: Compute Module
Topic: Raspberry Pi Compute Module PCM Audio Output MAX98357
Replies: 10
Views: 6843

Re: Raspberry Pi Compute Module PCM Audio Output MAX98357

Try creating/editing /etc/asound.conf to be:

Code: Select all

pcm.mmap0 {
  type mmap_emul
  slave {
    pcm "hw:0,0"
  }
}

pcm.!default {
  type plug
  slave {
    pcm mmap0
  }
}
then reboot and see if that fixes it?
by James Adams
Tue Jun 02, 2015 2:20 pm
Forum: Compute Module
Topic: Raspberry Pi Compute Module PCM Audio Output MAX98357
Replies: 10
Views: 6843

Re: Raspberry Pi Compute Module PCM Audio Output MAX98357

So I assume you are using GPIO18-21 for the PCM interface which looks OK from the GPIO settings. Your circuit diagram looks OK to me. Looks like the driver loaded OK and so the CM should be sending PCM data. Doesn't look like you used aplay to correctly play a wav file - there is an error you need a...
by James Adams
Tue Jun 02, 2015 7:42 am
Forum: Compute Module
Topic: Raspberry Pi Compute Module PCM Audio Output MAX98357
Replies: 10
Views: 6843

Re: Raspberry Pi Compute Module PCM Audio Output MAX98357

Hi can you try installing raspi-gpio as previously mentioned (NB name of tool and apt package now both raspi-gpio):

sudo apt-get update
sudo apt-get install raspi-gpio
sudo raspi-gpio get

And post the results?
by James Adams
Thu May 28, 2015 3:40 pm
Forum: Device Tree
Topic: STICKY: Device Tree Forum Area README
Replies: 9
Views: 14034

STICKY: Device Tree Forum Area README

From http://www.devicetree.org: "The Device Tree is a data structure for describing hardware. Rather than hard coding every detail of a device into an operating system, many aspects of the hardware can be described in a data structure that is passed to the operating system at boot time" Raspberry Pi...
by James Adams
Tue May 19, 2015 12:30 pm
Forum: Compute Module
Topic: dt-blob gpio28 and gpio29
Replies: 11
Views: 1298

Re: dt-blob gpio28 and gpio29

We really need to see your:
config.txt
dt-blob.dts
bcm2708-rpi-cm.dts
and also the output of the gpiostate tool once you've booted.

Can you put them on pastebin and provide a link?

James
by James Adams
Tue May 19, 2015 10:53 am
Forum: Compute Module
Topic: dt-blob gpio28 and gpio29
Replies: 11
Views: 1298

Re: dt-blob gpio28 and gpio29

@MrBool please add ignore_lcd=1 to your config.txt file to stop GPIO28 and 29 from being touched by the firmware. Note this is due to the recently added LCD driver for upcoming RPI Display incorrectly grabbing these pins. We will fix this properly in due course.

James
by James Adams
Sat Apr 04, 2015 11:37 am
Forum: Compute Module
Topic: Compute Module Boot on Windows
Replies: 7
Views: 1896

Re: Compute Module Boot on Windows

My recommendation for Windows is to use the WinDiskImager to write images to the Windows drive that appears once you have executed rpiboot, rather than use /dev/sdx via Cygwin - this is in the documentation but perhaps it needs to be more explicit.

James
by James Adams
Thu Apr 02, 2015 3:18 pm
Forum: Compute Module
Topic: Compute Module Boot on Windows
Replies: 7
Views: 1896

Compute Module Boot on Windows

We have updated the documentation on how to boot the Compute Module to include how to do it on Windows using Cygwin.

We've also tweaked the rpiboot software to compile and work under Cygwin.

Please use this thread to post any issues found.

Many thanks,
James.
by James Adams
Wed Aug 20, 2014 9:10 pm
Forum: HATs and other add-ons
Topic: Use of run header
Replies: 9
Views: 2721

Re: Use of run header

I think pogo sticks to contact the run header is in concord with not forcing the user to solder a header, so should be okay Not really. These pogo pin type arrangements are notoriously flaky so I'll restate what the docs say - don't use RUN if you want to call your board a HAT. Sorry them's the rul...

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