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by piras77
Fri Nov 03, 2017 12:30 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO max current
Replies: 34
Views: 72432

Re: GPIO max current

I would say that the 50mA global limit applies to simultaneous source and sink currents. So, you don't think that the different levels of voltage drops for sink and source do not matter and do not effect the power dissipation. You have someone who was on the design team of the chip in question stat...
by piras77
Thu Nov 02, 2017 4:11 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO max current
Replies: 34
Views: 72432

Re: GPIO max current

So what you are saying is that you trust a piece of paper more than the people involved with designing the chip? I trust/believe in information that can be verified. I'd suggest simply believing the people who are intimately familiar with the chip itself. That should be enough for ALL users. Which ...
by piras77
Thu Nov 02, 2017 3:32 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO max current
Replies: 34
Views: 72432

Re: GPIO max current

Anything that relies on producing more than the specified values is asking for trouble. I agree. What I'm argue is about the specification itself which has not been disclosed. Since that ain't going to happen, a discussion about the specified values appears to be rather pointless. So what remains i...
by piras77
Thu Nov 02, 2017 2:59 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI Slave (BSC Slave) Errata
Replies: 4
Views: 836

Re: SPI Slave (BSC Slave) Errata

Thanks for your feedback! :-)
by piras77
Thu Nov 02, 2017 2:48 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO max current
Replies: 34
Views: 72432

Re: GPIO max current

I suspect the 50mA isn't a hard limit enforced in the hardware, it's the point where you'll be creating issues. Within the SoC you're routing power from balls underneath to each block. How big... Since we don't know, it would be nice to get an explanation, preferably from Gert (since he posted here...
by piras77
Thu Nov 02, 2017 12:35 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO max current
Replies: 34
Views: 72432

Re: GPIO max current

Me. Is there some reference for this? It appears to me quite a bit too little. The resulting dissipation would be approx. something about 25mW (at dU 500mV), And, even though it is no contradiction, why did you write: "If you load each pin with 16mA the total current is 272mA. The 3V3 supply will c...
by piras77
Tue Oct 31, 2017 12:52 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI or BitBang via GPIO to 5v device and vice-versa
Replies: 45
Views: 5041

Re: SPI or BitBang via GPIO to 5v device and vice-versa

Thanks for the update! :-) (I watched one of Ultibo videos and was just curious to hear about your experience.)
by piras77
Mon Oct 30, 2017 4:29 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI or BitBang via GPIO to 5v device and vice-versa
Replies: 45
Views: 5041

Re: SPI or BitBang via GPIO to 5v device and vice-versa

Are there any news?

Since you use Ultibo (which appears to be a great one person show), what is your experience? There are a few bar metal approaches for the Pi, however, unlike them, Ultibo seems to provide some _real_ base to develop applications on bare metal.
by piras77
Mon Oct 30, 2017 3:47 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI_NO_CS flag in SPI_MODE seems to have no effect.
Replies: 5
Views: 770

Re: SPI_NO_CS flag in SPI_MODE seems to have no effect.

There are two (major) ways to run SPI from userland on a Pi. By directly accessing the peripheral. Or by using the kernel support (in Raspbian). Since you encountered problems with the kernel driver, and there wasn't any answer, my suggestion was to try it the direct way. Honestly, I can't find a pr...
by piras77
Wed Oct 25, 2017 7:00 pm
Forum: General discussion
Topic: GPIO Throughput
Replies: 3
Views: 318

Re: GPIO Throughput

You may want to have a look at this thread: viewtopic.php?f=44&t=191949
by piras77
Tue Oct 24, 2017 10:11 am
Forum: Troubleshooting
Topic: SPI Pins CE0 and CE1 stopped working correctly
Replies: 6
Views: 568

Re: SPI Pins CE0 and CE1 stopped working correctly

Are there any tests I could run? That's quite simple: If the pin is wired, disconnect it. Switch the pin mode to output. Set the output to High. Read the input. If the input reads Low, something is wrong. Set the output to Low. Read the input. If the input reads High, something is wrong. Use the to...
by piras77
Tue Oct 24, 2017 3:09 am
Forum: C/C++
Topic: ISR preemption of wiringPi ISR
Replies: 3
Views: 825

Re: ISR preemption of wiringPi ISR

As already said above, there is no real-time guarantee in Linux userland. Your process can get suspended any time and there is nothing you can do. However, you can improve your odds: you may try to run your program on a core that isn't used by the kernel to deal with interrupts (see taskset and /pro...
by piras77
Mon Oct 23, 2017 11:37 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Error in GPIO interrupt handling
Replies: 7
Views: 1272

Re: Error in GPIO interrupt handling

I honestly can't see any proof of a faulty GPEDS0 peripheral. I can't either follow your argument. You know there is only one interrupt "line" for the whole GPIO bank 0?! I can't even reproduce your experiment in your first post: I get a 100 increment whether your program runs or not. Raspbian image...
by piras77
Sun Oct 22, 2017 8:14 am
Forum: Beginners
Topic: Raspberry 3 B needs a cooling system?
Replies: 7
Views: 1655

Re: Raspberry 3 B needs a cooling system?

My question is whether I should also put some cooling system. The SOC checks on its own the temperature and throttles down when it reaches 80°C. So it protects itself against damage. In this sense, it doesn't require cooling. There must be some significant CPU load for more than a few seconds in or...
by piras77
Sat Oct 21, 2017 7:17 am
Forum: Troubleshooting
Topic: Am I asking too much of a Pi Zero W?
Replies: 11
Views: 930

Re: Am I asking too much of a Pi Zero W?

Why should a memory leak in a user application crash a Pi?
by piras77
Fri Oct 20, 2017 7:48 pm
Forum: Troubleshooting
Topic: Am I asking too much of a Pi Zero W?
Replies: 11
Views: 930

Re: Am I asking too much of a Pi Zero W?

I don't see why your application might crash your Pi. There are many things that can crash a Pi. If you're lucky you'll see a relevant diagnostic message in /var/log/messages, /var/log/syslog or /var/log/kern.log. However, events like a failed power supply, an electromagnetic event, a failing wire, ...
by piras77
Fri Oct 20, 2017 7:35 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI_NO_CS flag in SPI_MODE seems to have no effect.
Replies: 5
Views: 770

Re: SPI_NO_CS flag in SPI_MODE seems to have no effect.

Well, this might not really help, still, there is always the possibility to access the peripheral directly from userland. Real-time behavior is feasible thru DMA access. If you need other CE/CS signals than the one controlled by the SPI peripheral you still can daisy chain DMA control blocks to acce...
by piras77
Fri Oct 20, 2017 7:21 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Error in GPIO interrupt handling
Replies: 7
Views: 1272

Re: Error in GPIO interrupt handling

After some days of investigation I'm quite sure, that the GPEDS register of the GPIO controller is not implemented correctly (controller bug). In my software I directly access the peripherals from userland. And in my experience, the event detect status register works fine. In my application, the se...
by piras77
Tue Oct 17, 2017 7:18 am
Forum: Beginners
Topic: Problems compiling code. QT stufff
Replies: 4
Views: 456

Re: Problems compiling code. QT stufff

Maybe this helps: https://stackoverflow.com/questions/397 ... by-default

(There may be several Qt installations on your system; you can select among them by env variable, symlink or direct call.)
by piras77
Tue Oct 17, 2017 7:02 am
Forum: Troubleshooting
Topic: MCP3008 with output all 0?
Replies: 4
Views: 397

Re: MCP3008 with output all 0?

CLK = 18 MISO = 23 MOSI = 24 CS = 25 What are these numbers? What program do you use? What is the actual wiring? That's the Pi-3's pinout: https://pinout.xyz SCLK: 11 (23) MISO: 9 (21) MOSI: 10 (19) CE0: 8 (24) In your screenshot, there is only a clock-pulse. No data is transmitted (neither sent no...
by piras77
Thu Oct 05, 2017 7:36 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple I2S ports on RPi 3
Replies: 1
Views: 440

Re: Multiple I2S ports on RPi 3

For my project I need to connect multiple (more than 2) I2S microphones to RPi 3. I see several different ways how to do that, on the other hand I'd like stay with minimum (or none) additional hardware. The Pi supports an I2S peripheral. See §8 in the datasheet https://www.raspberrypi.org/app/uploa...
by piras77
Wed Oct 04, 2017 5:28 pm
Forum: Beginners
Topic: Current draw from GPIO pins
Replies: 28
Views: 3255

Re: Current draw from GPIO pins

All I said was 16mA from a GPIO pin and 500mA from the power supply pins.
davidcoton wrote:
Wed Oct 04, 2017 5:13 pm
you can draw ... from one or more pins, up to the recommended maximum of 50mA ... through the SOC
That would be quite interesting. Do you have a source for that?
by piras77
Wed Oct 04, 2017 6:38 am
Forum: Beginners
Topic: Current draw from GPIO pins
Replies: 28
Views: 3255

Re: Current draw from GPIO pins

The reference to the pad-control datasheet should have made it clear (by context).

However, if you like, you may want to make a future reference: GPIO Pin = BCM's SOC GPIO Pin on the Pin Header; Power Pin = Power Supply on the Pin Header
by piras77
Wed Oct 04, 2017 6:13 am
Forum: Beginners
Topic: Current draw from GPIO pins
Replies: 28
Views: 3255

Re: Current draw from GPIO pins

The GPIO pins (at 3V3) are not intended for powering sensors, nor is the 3V3 supply really suitable (amongst other reasons, you could introduce noise on the 3V3 rail). What do you mean by "intended"? Do you mean your personal opinion? Insofar as I see it, you can do whatever you want as long as you...
by piras77
Mon Oct 02, 2017 7:50 am
Forum: Beginners
Topic: Not getting any output from MCP3008
Replies: 5
Views: 557

Re: Not getting any output from MCP3008

Well, if you are sure that you did everything right, then, as the only conclusion, something must be broken. In my experience, this is rarely the case, so you may want to check your setup again. You may also want to have a look at the datasheet: https://cdn-shop.adafruit.com/datasheets/MCP3008.pdf A...

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