Raspberry Pi Forums

MrBool

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?

MrBool

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...

MrBool

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]

MrBool

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...

MrBool

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...

MrBool

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.

MrBool

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...

MrBool

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?

MrBool

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?

MrBool

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.

MrBool

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 &...

MrBool

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.

MrBool

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.

MrBool

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 ...

MrBool

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...

MrBool

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.

MrBool

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...

MrBool

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] # ...

MrBool

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?

MrBool

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...

MrBool

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?

MrBool

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...

MrBool

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...

MrBool

b.ozgen wrote: ↑
Tue Nov 24, 2020 3:24 pm
Which OS do you run?

Raspbian.

MrBool

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

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

Search found 141 matches

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

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

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

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

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

Re: UART and HDMI console

Re: UART and HDMI console

UART and HDMI console

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

Re: CM4 Under-voltage detected and serial port

Re: CM4 Under-voltage detected and serial port

Re: CM4 Under-voltage detected and serial port

Re: CM4 Under-voltage detected and serial port

[SOLVED] CM4 Under-voltage detected and serial port

Re: led1 CM4

led1 CM4

dtoverlay gpio-shutdown and triggerhappy fail

config.txt - gpio command and GPIO Filter

config.txt sections

USB_OTG_ID voltage during power up

Re: Force CM4 bootloader without jumper

Force CM4 bootloader without jumper

CM4 I2C GPIO

Re: Compute Module Ethernet MAC Address

CM4 MAC address