Raspberry Pi Forums

drgeoff

You can feed %v directly into the expansion header, but take care as this bypasses protection circuitry. So you need to make sure the supply is within range and you get the polarity right. That is false information about protection circuitry. On a RPi4B there is no polyfuse. The 5 volt pin on the G...

drgeoff

jamesh wrote: ↑
Thu Feb 27, 2020 12:22 pm
I don't think I've ever run out of memory on a 4GB Pi TBH.

I'm sure that if there is ever an 8Gbyte RPi4B there will be badly written software which doesn't run comfortably in 4 Gbyte.

drgeoff

davidcoton wrote: ↑
Thu Feb 27, 2020 11:53 am
The FET converts the 3V3 GPIO signal to 12V for the fan.

That is badly worded.

The 3.3 volt PWM GPIO signal causes the FET to switch on and off the 12 volt supply to the fan.

drgeoff

HermannSW wrote: ↑
Thu Feb 27, 2020 11:04 am
That is really nice!
But among the 9 German Raspberry distributors only one had a reduced price for the 2GB version.
Not 35$, but 38.50€ = 41.02$.

It is $35 plus local taxes.

drgeoff

You probably have already done this but if not try the problem RPi4B with one of the PSUs that the other RPi4s do boot with.

drgeoff

Use a USB to "real RS-232" module to connect RPi to the tool. A USB to "TTL-serial", even one that has 3.3 volt levels on the TTL side will not work.

The "real RS-232" module will have a 9 pin D-type connector.

drgeoff

Did you initiate a software shutdown, wait for it to complete and then remove power before taking the card out?

drgeoff

The diagrams seem to show it being connected between the PC and keyboard No, the diagrams don't show or even imply that. Look again at the "System Connection Method" pictures. The keyboard is plugged into the "Input Tool", which is then plugged into the PC via a Keyboard cable. There are 2 versions...

drgeoff

rpdom wrote: ↑
Tue Feb 25, 2020 6:48 pm
The diagrams seem to show it being connected between the PC and keyboard

No, the diagrams don't show or even imply that.

drgeoff

Two possible modes?

One is RS232 with the normal asynchronous transfer. 2400 baud, 1 start, 8 data, 1 stop.

Another is synchronous. Uses the clock and transfers 52 bits. No start and stop bits.

Maybe the latter one is the native mode and the former is only available when using the Input Tool.

drgeoff

Sometime connecting Pi to TV via HDMI we need to make some changes in config. file but it is hit and trial to assign values. For connecting it to TV just bought HDMI to VGA connect it to TV it will automatically detects pi. Many people find that using an HDMI to VGA converter is more hit and miss t...

drgeoff

OK so it is RS232 compatible. But not directly to the GPIO header pins on a RPi. (Don't need bit-banging so you can ignore that.)

You are incorrect about 52 bits. It is 13 ASCII characters each encoded in 8 bits.

2400 baud, 1 start bit, 1 stop bit, no parity.

drgeoff

That dial gauge is NOT using an RS232 interface. It is a custom serial interface. You may need to "bit-bang" it. You'll need more details of the electrical signal timing etc. Things like whether the clock is generated by the gauge or must be supplied to it, which edge of the clock is used etc?

drgeoff

ragishtin wrote: ↑
Tue Feb 25, 2020 12:22 pm
I need to use serial communication because it's a requirement in the project

Ethernet is a serial communication.

drgeoff

Without knowing what signals are on the cable it is not possible to suggest an electronic switch.

Despite the suggestion above to use an HDMI switch you have more chance of winning the lottery than succeeding to get one of those to switch between two 50 way cables.

drgeoff

But now when I try sudo reboot, I get "Putty Fatal Error: Remote side unexpectedly closed connection" and I am scared to create a new host name and password because it will ask to reboot, and if I get an error during a reboot after I change my password I might get locked out. Is there anything I ca...

drgeoff

DirkS wrote: ↑
Sun Feb 23, 2020 7:58 pm
If you mean the bits of metal you can see through the hole in the bottom left of the slot: I think that's the read-only switch / sensor (not used on the Pi)

There is no "read-only" switch on a micro-SD card.

drgeoff

This does sound wierd - especially as many of us have recommended switched mains sockets to avoid having to plug/unplug the USB-c connector. Is the OKDO PSU slow to bring up its output? I can't think of anything else it could be! I have one of those Okdo PSUs (UK plug version) powering a RPi4B 4Gby...

drgeoff

viewtopic.php?f=37&t=261683#p1594299

drgeoff

Read the "not booting" sticky.

drgeoff

this will go on forever until locked.... ....or until the wait is over.... ;) It's an inevitability of any "it will be done when it's done" position when coupled with no updates on progress. No one can truly know if what was said back then still applies or doesn't, so the only way to find out is to...

drgeoff

If with 2 official PSUs (one at a time!), no micro-SD card inserted, nothing in the USB ports and nothing connected to the GPIO header, the red LED is flashing I'd say you now have a hardware fault on the RPi board.

drgeoff

Hello Thanks but still same blinking. Flashes are regular and wont become constant, thats really weird I tried with phone charger (5v 2A) it does not blink anymore but no green light at boot and wont read my sd card. The 2 official chargers (5V 3A) give red flashing, its really really strange!! How...

drgeoff

rowan.bradley wrote: ↑
Fri Feb 21, 2020 6:43 pm
6. Click Flash. It should write the image to the card. It apparently gave a verification error, which I ignored for now.

Nuff sed!

drgeoff

Try removing/unplugging that fan thing. I suspect it is faulty and overloading your PSUs.

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