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by MrBool
Mon Oct 25, 2021 9:25 am
Forum: Compute Module
Topic: CM4 Unable to open '/dev/fb0': No such file or directory
Replies: 9
Views: 350

Re: CM4 Unable to open '/dev/fb0': No such file or directory

6by9 wrote:
Mon Oct 25, 2021 9:15 am
What is your actual issue?
I just want to know do the tones of messages returned by "vcdbg log msg" in the fresh image are normal or not?
by MrBool
Mon Oct 25, 2021 9:07 am
Forum: Compute Module
Topic: CM4 Unable to open '/dev/fb0': No such file or directory
Replies: 9
Views: 350

Re: CM4 Unable to open '/dev/fb0': No such file or directory

So you want a framebuffer even though there is no display attached? No, I don't want to framebuffer though there is no display attached. If the HDMI cable is connected I want to keep HDMI on. In the case of no cable connection, I want to turn off HDMI. It works as expected without hdmi_force_hotplu...
by MrBool
Mon Oct 25, 2021 8:53 am
Forum: Compute Module
Topic: CM4 Unable to open '/dev/fb0': No such file or directory
Replies: 9
Views: 350

Re: CM4 Unable to open '/dev/fb0': No such file or directory

I make some tests and in the case when I use hdmi_force_hotplug=1 I received: root@raspberrypi:~# tvservice -s state 0x6 [DVI CUSTOM RGB full 4:3], 640x480 @ 60.00Hz, progressive without hdmi_force_hotplug=1 works as expected (HDMI is off): root@raspberrypi:~# tvservice -s state 0x120001 [TV is off]
by MrBool
Mon Oct 25, 2021 8:44 am
Forum: Compute Module
Topic: CM4 Unable to open '/dev/fb0': No such file or directory
Replies: 9
Views: 350

Re: CM4 Unable to open '/dev/fb0': No such file or directory

Have you tried with "hdmi_force_hotplug=1" in config.txt? I just tried. With "hdmi_force_hotplug=1" is fine. I want to automatically turn off the HDMI after boot if no HDMI cable is connected. I have added to /etc/rc.local: tvservice -n | grep -q 'No device present' && t...
by MrBool
Mon Oct 25, 2021 7:54 am
Forum: Compute Module
Topic: CM4 Unable to open '/dev/fb0': No such file or directory
Replies: 9
Views: 350

CM4 Unable to open '/dev/fb0': No such file or directory

I installed the latest Raspberry Pi OS on CM4. If the HDMI cable is not connected I get: root@raspberrypi:~# vcdbg log msg debug_sym: vc_mem_copy: Unable to open '/dev/fb0': No such file or directory(2) debug_sym: vc_mem_copy: Unable to open '/dev/fb0': No such file or directory(2) debug_sym: vc_mem...
by MrBool
Wed Oct 13, 2021 10:31 am
Forum: General discussion
Topic: UART and HDMI console
Replies: 6
Views: 253

Re: UART and HDMI console

I see the messages on the serial console but they are different than on the HDMI console. At what point and in what way are they different? For example, during boot the last info before login is [ 4.861381] i2c /dev entries driver On the HDMI at the same time I see many other messages.
by MrBool
Wed Oct 13, 2021 9:40 am
Forum: General discussion
Topic: UART and HDMI console
Replies: 6
Views: 253

Re: UART and HDMI console

Yes. It's configured like that by default with RaspiOS. There's an option in sudo raspi-config for the serial console. Did you mean "P6 Serial Port Enable/disable shell messages on the serial connection" option? I see the messages on the serial console but they are different than on the H...
by MrBool
Wed Oct 13, 2021 9:20 am
Forum: General discussion
Topic: UART and HDMI console
Replies: 6
Views: 253

UART and HDMI console

I'm using the Lite version of Pi OS. I noticed that the HDMI console has more info. Is possible to configure the UART console to show the same info as HDMI console?
by MrBool
Thu Oct 07, 2021 10:31 am
Forum: Compute Module
Topic: [SOLVED] CM4 Under-voltage detected and serial port
Replies: 12
Views: 571

Re: [SOLVED] CM4 Under-voltage detected and serial port

As I understand the Input Voltage Good Threshold was the reason for the minimum voltage in the CM4 datasheet 4.75V. Even though the converter can be supplied with voltage down to 4V.

The warning is generated based on the Input voltage status register read by I2C?
by MrBool
Thu Oct 07, 2021 10:17 am
Forum: Compute Module
Topic: [SOLVED] CM4 Under-voltage detected and serial port
Replies: 12
Views: 571

Re: CM4 Under-voltage detected and serial port

PhilE wrote:
Thu Oct 07, 2021 9:26 am
The MXL UV threshold is 4.63V. Are you sure your measurement is accurate?
I just repeated the measurement. This time I use an oscilloscope. Indeed for a very short time the voltage drop dawn below the input voltage good threshold.
by MrBool
Thu Oct 07, 2021 9:19 am
Forum: Compute Module
Topic: [SOLVED] CM4 Under-voltage detected and serial port
Replies: 12
Views: 571

Re: CM4 Under-voltage detected and serial port

But trying to work around the symptoms of under-voltage is like [ insert favourite metaphor about pointless activity while avoiding the real problem here ]. I know what you mean but the question is why for CM4 under-voltage warning is set so high. I received it for 4,9V. I understand that for the &...
by MrBool
Thu Oct 07, 2021 9:04 am
Forum: Compute Module
Topic: [SOLVED] CM4 Under-voltage detected and serial port
Replies: 12
Views: 571

Re: CM4 Under-voltage detected and serial port

jamesh wrote:
Thu Oct 07, 2021 8:55 am
MrBool wrote:
Thu Oct 07, 2021 8:52 am
What about "avoid_warnings=2"? I don't use turbo mode and I don't want to use it.
Have you tried it?
I tried it. It disables the under-voltage warnings and I can use the serial console.
by MrBool
Thu Oct 07, 2021 8:52 am
Forum: Compute Module
Topic: [SOLVED] CM4 Under-voltage detected and serial port
Replies: 12
Views: 571

Re: CM4 Under-voltage detected and serial port

I'm running the latest Raspberry Pi OS Lite (release date: May 7th 2021).

What about "avoid_warnings=2"? I don't use turbo mode and I don't want to use it.
by MrBool
Thu Oct 07, 2021 8:38 am
Forum: Compute Module
Topic: [SOLVED] CM4 Under-voltage detected and serial port
Replies: 12
Views: 571

[SOLVED] CM4 Under-voltage detected and serial port

During testing my board with CM4 and UPS I noticed strange serial port behavior (UART0 - GPIO14, GPIO15). When the voltage supply goes slowly down (UPS working) I receive in the HDMI console: "Under-voltage detected! (0x00050005)" and it is correct but in the serial console, I see strange ...
by MrBool
Fri Oct 01, 2021 2:05 pm
Forum: Compute Module
Topic: led1 CM4
Replies: 3
Views: 287

Re: led1 CM4

Thank you for your reply. I do not understand why I should make a script. I just want to use in my config.txt dtoverlay=gpio-led,gpio=20,label=led1 When the "first" led1 (after my overlay it is led1_1) is created? I just want to remove create led1 before gpio-led overlay. BTW. I wonder why...
by MrBool
Fri Oct 01, 2021 1:00 pm
Forum: Compute Module
Topic: led1 CM4
Replies: 3
Views: 287

led1 CM4

I'm using my overlay for led1 on the CM4. I noticed that there is already led1:

Code: Select all

leds-gpio leds: Led led1 renamed to led1_1 due to name collision
How can I remove the led1 from the system? I just want to use my led1 overlay.
by MrBool
Wed Sep 22, 2021 1:53 pm
Forum: Troubleshooting
Topic: dtoverlay gpio-shutdown and triggerhappy fail
Replies: 0
Views: 117

dtoverlay gpio-shutdown and triggerhappy fail

I noticed that when I use overlay: dtoverlay=gpio-shutdown,gpio_pin=4,active_low=1,gpio_pull=up,debounce=1500 I receive the error: systemd-udevd[159]: Process '/usr/sbin/th-cmd --socket /var/run/thd.socket --passfd --udev' failed with exit code 1. Changing the overlay parameters does not change anyt...
by MrBool
Wed Sep 15, 2021 1:32 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: config.txt - gpio command and GPIO Filter
Replies: 0
Views: 321

config.txt - gpio command and GPIO Filter

Does gpio command in config.txt work immediately or after all config.txt load? I need to use GPIO filter in config.txt but before filtering, change GPIO to input pull down and after filtering change GPIO to output pull up and next set as a gpio-poweroff pin. Example: gpio=4=in gpio=4=pd [gpio4=1] # ...
by MrBool
Wed Sep 15, 2021 11:50 am
Forum: Compute Module
Topic: config.txt sections
Replies: 3
Views: 391

config.txt sections

I have several different devices based on CM3 and CM4, I would like our customers to share one system image file. The only difference between the images is the entries in config.txt. Is it possible to create sections in config.txt that will be selected based on the device model?
by MrBool
Sat Mar 20, 2021 4:26 pm
Forum: Compute Module
Topic: USB_OTG_ID voltage during power up
Replies: 0
Views: 213

USB_OTG_ID voltage during power up

The CM4 datasheet says: No reverse voltage must be applied to any pin or power up may be prevented, i.e. during power down/off no pin may have external voltage applied otherwise this may prevent power up. The CM4 IO board has USB_OTG_ID signal connected to the +5V micro USB slave port by the voltage...
by MrBool
Fri Mar 19, 2021 8:55 am
Forum: Compute Module
Topic: Force CM4 bootloader without jumper
Replies: 3
Views: 366

Re: Force CM4 bootloader without jumper

Thank you for your reply. GPIO conditionals is a good feature but unfortunately unhelpful if you are flashing CM4 for the first time.

BTW. What if there is no operating system available? Does the firmware activate the USB bootloader?
by MrBool
Mon Mar 15, 2021 9:51 am
Forum: Compute Module
Topic: Force CM4 bootloader without jumper
Replies: 3
Views: 366

Force CM4 bootloader without jumper

I noticed that the CM4 IO board requires a jumper eMMC Boot to force bootloader. I want to use +5V signal from the USB device port to switch CM4 to bootloader mode like on my previous device with CM3. For that, I'm going to use a transistor controlled by a +5V signal from the USB device port. It wil...
by MrBool
Fri Feb 19, 2021 2:05 pm
Forum: Compute Module
Topic: CM4 I2C GPIO
Replies: 1
Views: 413

CM4 I2C GPIO

I want to use I2C lines ID_SD, ID_SC, SDA0, SCL0 as GPIO. For the ID_SD, ID_SC is clear to me that I have to add to the config file force_eeprom_read=0. I assume that there will be no changes in these signals by the firmware. What about SDA0, SCL0? The datasheet says "This internal I2C bus is n...
by MrBool
Thu Nov 26, 2020 7:12 am
Forum: Compute Module
Topic: Compute Module Ethernet MAC Address
Replies: 19
Views: 7537

Re: Compute Module Ethernet MAC Address

b.ozgen wrote:
Tue Nov 24, 2020 3:24 pm
Which OS do you run?
Raspbian.
by MrBool
Fri Nov 20, 2020 2:42 pm
Forum: Compute Module
Topic: CM4 MAC address
Replies: 7
Views: 837

CM4 MAC address

I use LAN9514 with MAC stored in EEPROM. It works well with CM3.

How can I achieve similar functionality with embedded Ethernet in CM4?

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