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by demedeirosa
Thu Apr 18, 2019 8:04 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: WM8731 Output working, no input?
Replies: 0
Views: 64

WM8731 Output working, no input?

Hi all, I've got a WM8731 on the MikroE board. Following this: https://github.com/raspberrypi/linux/issues/1302 I was able to get the sound output working with no issues. However, I cannot seem to get the microphone input working. Using arecord, with the -V parameter set, I get no input on the VU me...
by demedeirosa
Thu Apr 11, 2019 2:51 pm
Forum: Compute Module
Topic: LAN and Audio with the CM3
Replies: 0
Views: 157

LAN and Audio with the CM3

Hi all, Making some changes to an existing product where we need to add LAN capability and audio, both output and input (mic). With respect to the LAN interface, is there a particular advantage to using something like the LAN9512 over the ENC28J60? I have the SPI pins available, so I could go in eit...
by demedeirosa
Tue Sep 04, 2018 12:34 pm
Forum: Advanced users
Topic: Using a tlc591xx, need kernel module help
Replies: 2
Views: 217

Re: Using a tlc591xx, need kernel module help

Thank you for the information.

Other using a kernel module, is there any additional way to have the i2c commands be sent early on in the boot process? To date, my programs have been launched using rc.local. However, these are usually python scripts.
by demedeirosa
Tue Sep 04, 2018 12:05 pm
Forum: Advanced users
Topic: Using a tlc591xx, need kernel module help
Replies: 2
Views: 217

Using a tlc591xx, need kernel module help

Hi all, I am using a TLC59108 LED driver on a custom PCB with a CM3. I want to have the LED driver turn on very early in the boot process. Presumably the best way to do this is with a kernel module. It appears that a kernel module exists here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds...
by demedeirosa
Fri Aug 17, 2018 4:57 pm
Forum: Compute Module
Topic: Determining via GPIO is the OS has fully shutdown?
Replies: 2
Views: 636

Determining via GPIO is the OS has fully shutdown?

Hi all, Using a CM3L on a custom project. I currently have a supercap backup setup where I am monitoring a GPIO via a script, and shutting down immediately if the GPIO goes LOW. My current issue is that my supercap has a bit more energy than is required, and it keeps the 3.3V and 1.8V supplies on un...
by demedeirosa
Thu Aug 09, 2018 12:35 pm
Forum: Compute Module
Topic: GPIO40-43 interrupt availability
Replies: 0
Views: 549

GPIO40-43 interrupt availability

Hi all, I am using a CM3 on a project, and I was using pigpio for interrupts on GPIO28-31. I recently had to add GPIO40-43 and I learned that pigpio will not handle interrupts on pins > 31. Is this a hardware or software limitation? I believe it is a software limitation. if so, can anyone point me t...
by demedeirosa
Mon Jul 30, 2018 12:51 pm
Forum: Compute Module
Topic: Troubleshooting CM3/CM3L custom PCB
Replies: 6
Views: 767

Re: Troubleshooting CM3/CM3L custom PCB

Thanks for all of the help! The HDMI_SDA pull up was the issue, threw a 10k pull up on it and it booted up immediately with applied power. I wonder why this isnt called out in the datasheet? Thanks for all the LAN info as well. This project is pretty straightforward and doesn't require a LAN connect...
by demedeirosa
Sun Jul 29, 2018 9:34 am
Forum: Compute Module
Topic: Troubleshooting CM3/CM3L custom PCB
Replies: 6
Views: 767

Re: Troubleshooting CM3/CM3L custom PCB

Interesting! I left all HDMI lines unconnected since I am not using them, and it mentions to leave them open in the datasheet. Any other surprises to be aware of?
by demedeirosa
Sat Jul 28, 2018 10:52 am
Forum: Compute Module
Topic: Troubleshooting CM3/CM3L custom PCB
Replies: 6
Views: 767

Re: Troubleshooting CM3/CM3L custom PCB

Hi all, Ended up determining it was an error on the PCB. USB_DP and USB_DM were swapped. A little bit of wire wrapped wire solved the problem until we can send out new boards. Here's another question, it seems to take a significant amount of time for the system to boot on my PCB vs the IO board. Is ...
by demedeirosa
Fri Jul 27, 2018 12:38 pm
Forum: Compute Module
Topic: Troubleshooting CM3/CM3L custom PCB
Replies: 6
Views: 767

Troubleshooting CM3/CM3L custom PCB

Hi all, I just put together my first CM3/CM3L carrier PCB. I'm having an issue getting it to boot correctly. Heres a video of the boot LED, it doesnt appear to match the LED on the RPI carrier PCB. In addition, I see no activity on the USB bus. On the RPI IO pcb I see activity immediately. https://p...
by demedeirosa
Mon Jul 23, 2018 2:38 pm
Forum: Compute Module
Topic: Is the CM3 less susceptible to power loss corruption?
Replies: 0
Views: 368

Is the CM3 less susceptible to power loss corruption?

Hi all, Since the CM3 uses emmc instead of an SD card, is it any less susceptible to corruption resulting from power loss? I know that there are ways around this, including read-only file systems and safe-shutdown circuits (which i'm implementing). I am not familiar with storage technologies in gene...
by demedeirosa
Thu Jul 19, 2018 3:07 pm
Forum: Compute Module
Topic: SDX Termination
Replies: 2
Views: 597

Re: SDX Termination

Thanks for the information!
by demedeirosa
Wed Jul 18, 2018 12:20 pm
Forum: Compute Module
Topic: SDX Termination
Replies: 2
Views: 597

SDX Termination

Hi All, Working on a design for a CM3, but I am including SD card provisions for a CM3 Lite since it looks like stock on the CM3 is limited currently. I reviewed the schematic, and it appears that none of the SDX_x lines are terminated. Is there a particular reason why? All documentation i've come a...
by demedeirosa
Mon Jul 16, 2018 3:34 pm
Forum: Compute Module
Topic: Help getting DPI touchscreen to work on Compute Module 3
Replies: 20
Views: 3341

Re: Help getting DPI touchscreen to work on Compute Module 3

I am no expert, but im going through some of the same issues now. Did you try

Code: Select all

raspi-gpio get
to see if your io is configured correctly?
by demedeirosa
Wed Jul 11, 2018 4:50 pm
Forum: Compute Module
Topic: CM3 using DPI, I2C and SPI
Replies: 6
Views: 1305

Re: CM3 using DPI, I2C and SPI

PhilE,

Thank you for all of the help, I really appreciate it!!
by demedeirosa
Wed Jul 11, 2018 3:25 pm
Forum: Compute Module
Topic: CM3 using DPI, I2C and SPI
Replies: 6
Views: 1305

Re: CM3 using DPI, I2C and SPI

Thanks everyone for all of the info.

From taking a quick look, the device tree configuration doesn't seem terribly difficult. Is that true? I haven't had much experience with device tree at all.

Thanks!
by demedeirosa
Wed Jul 11, 2018 2:06 pm
Forum: Compute Module
Topic: CM3 using DPI, I2C and SPI
Replies: 6
Views: 1305

CM3 using DPI, I2C and SPI

Hi all, I am working on a project where I would like to use the CM3. According to info from the Adafruit website, DPI uses GPIO2-21. Presumably this pinout naming convention is the same from the other models to the CM. Looking at the CM datasheet, it appears that I2C0 is available on pins GPIO0 (SDA...

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