Go to advanced search

by bitbank
Mon Jul 31, 2017 5:07 pm
Forum: General discussion
Topic: ssh not being able to log in, ssh keys appearing, usisng a Mac with OS Sierra
Replies: 7
Views: 1151

Re: ssh not being able to log in, ssh keys appearing, usisng a Mac with OS Sierra

Do you have more than one Raspberry Pi with the same network name? If you log into RPI #1, then log into RPI #2, you'll get this error because they're 2 different SHA signatures with the same network name. You can either do as instructed above or rename one of your RPi's.
by bitbank
Sun Jul 30, 2017 3:44 pm
Forum: Beginners
Topic: Transfer files from laptop to rPI with HDD
Replies: 23
Views: 3883

Re: Transfer files from laptop to rPI with HDD

If you have Linux or MacOS laptop, an easy way is to use SCP (secure copy). You can do something like this:

JimsMacBook:my_files$ scp *.mpa [email protected]:/home/pi/my_movies

It will also accept an IP address in place of a network name:

scp *.mpa [email protected]:/home/myuser/my_movies
by bitbank
Wed Jul 26, 2017 8:08 pm
Forum: Other projects
Topic: 'reading' text in pdf to store the file in the right folder
Replies: 11
Views: 2047

Re: 'reading' text in pdf to store the file in the right folder

I've written my own PDF file parser for viewing scanned images. It also happens to check every object in the file and can inflate (decompress) the compressed text objects. Can you please post a sample PDF (not a screen shot) and I'll see if the text is possible to extract.
by bitbank
Wed Jul 26, 2017 7:39 pm
Forum: Beginners
Topic: Unable to access pigpio without sudo.
Replies: 3
Views: 2027

Re: Unable to access pigpio without sudo.

As a follow-up to my own post, I discovered a way to make it work. The USB audio adapter I'm using doesn't work when the calling program has root privilege. The way around this is to give the executable root privilege, but run it as user. To give an executable root privilege: sudo chown root:root my...
by bitbank
Wed Jul 26, 2017 1:21 pm
Forum: Bare metal, Assembly language
Topic: Is it possible to clear/preload the L1 cache contents?
Replies: 10
Views: 1932

Re: Is it possible to clear/preload the L1 cache contents?

Thanks again David, Just to confirm, so the only way to done this is to use bare metal programming on Pi or is there any other way to do this as well ? Starting in the ARMv5 instruction set, the PLD (cache preload hint) instruction was added. You can use this instruction in a bare metal environment...
by bitbank
Wed Jul 26, 2017 11:54 am
Forum: Bare metal, Assembly language
Topic: Optimizing code for 64 byte cache line
Replies: 2
Views: 919

Re: Optimizing code for 64 byte cache line

The Cortex-A7 in the RPi3 has a 64-byte cache line size (L2 cache). See info here: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0503i/CHDCBBIE.html It is useful to align accesses on 64-byte boundaries. For example, if you're reading a 32-bit integer that straddles a cache line boun...
by bitbank
Tue Jul 25, 2017 3:09 pm
Forum: Automation, sensing and robotics
Topic: Laser Ranging Sensor (VL53L0X)
Replies: 1
Views: 1937

Re: Laser Ranging Sensor (VL53L0X)

I just ordered one and will report back my results after I've tested it. Update: I received it today and discovered that ST Microdevices is trying to hide the details of the sensor by only sharing a "library" to access its functions - the data sheet doesn't give any details about the register map or...
by bitbank
Sun Jul 23, 2017 12:48 am
Forum: Troubleshooting
Topic: Analog audio with static
Replies: 8
Views: 2899

Re: Analog audio with static

I had this issue with the older PWM driver, but not the new one. The new one doesn't sound perfect at the default volume level (40/100), but if you set the "virtual" volume to 100/100, it sounds quite good and the static disappears.
by bitbank
Sun Jul 23, 2017 12:39 am
Forum: Beginners
Topic: 2.4"TFT display to Pi pin wirings.
Replies: 13
Views: 2619

Re: 2.4"TFT display to Pi pin wirings.

It appears you have an Arduino 'shield' version of the display. Arduinos use 5V logic and Raspberry Pis use 3.3V logic. As far as I know, you can't mix them without level translators. It's also an 8-bit parallel interface. An RPi could potentially control it, but it's easier to work with 4-wire SPI ...
by bitbank
Sat Jul 22, 2017 4:07 pm
Forum: Beginners
Topic: 2.4"TFT display to Pi pin wirings.
Replies: 13
Views: 2619

Re: 2.4"TFT display to Pi pin wirings.

tony1812 wrote: I said 2.4" TFT.
There are a wide variety of these screens floating around with different pin-outs, controller chips, etc. Take a photo of it and post it here and we should be able to help you. If the pins are nicely labeled (e.g. C/S, D/C, LED, MOSI, etc. that will make it easier still.
by bitbank
Tue Jul 18, 2017 9:09 pm
Forum: Gaming
Topic: Latest PWM driver sounds good
Replies: 0
Views: 412

Latest PWM driver sounds good

In the 'maker' community of portable RPi gaming systems, the PWM audio circuit/driver has a bad reputation. With the latest Raspbian and with the volume set to 100/100, the PWM output sounds quite good. Here's a PiPlay Portable with the simplest possible pwm circuit (10nf cap + 270ohm resistor): htt...
by bitbank
Tue Jul 11, 2017 3:25 pm
Forum: Beginners
Topic: Unable to access pigpio without sudo.
Replies: 3
Views: 2027

Re: Unable to access pigpio without sudo.

joan - I'm in need of your advice. My C application uses PIGPIO to access GPIO pins and the SPI bus. It also uses SDL2 to output audio. When running as root, USB audio devices fail to open, but the bcm2835 PWM audio driver still works. Is there any way to use your library for GPIO/SPI without having...
by bitbank
Sat Jul 08, 2017 9:25 pm
Forum: Automation, sensing and robotics
Topic: Best Hunidity and temperature sensor
Replies: 4
Views: 2226

Re: Best Hunidity and temperature sensor

I second the vote for the BME280. It's only weakness appears to be a temperature offset (reads a few degrees too warm). Otherwise, quite impressive for the price.
by bitbank
Thu Jul 06, 2017 7:26 pm
Forum: General discussion
Topic: 3.5 gpio screen not working
Replies: 5
Views: 1183

Re: 3.5 gpio screen not working

That looks like a clone of the waveshare 3.5" display (waveshare35a dtoverlay). I have a clone of the same board from a different vendor that has the same layout and chips visible. You can get the driver here: https://github.com/swkim01/waveshare-dtoverlays and add this line to /boot/config.txt: dto...
by bitbank
Thu Jul 06, 2017 6:46 pm
Forum: General discussion
Topic: 3.5 gpio screen not working
Replies: 5
Views: 1183

Re: 3.5 gpio screen not working

Please post a photo of the connector side of the board. It should provide enough info for us to help you.
by bitbank
Thu Jul 06, 2017 4:10 pm
Forum: Graphics programming
Topic: opengl what to use to draw a window
Replies: 2
Views: 1843

Re: opengl what to use to draw a window

The new driver (non-experimental) seems to be much more stable than the old experimental driver. The old one would crash when I used SDL2 in a window. For my usage, I can make use of the hardware accelerated driver by creating a SDL2 window with a 'streaming' texture. With that arrangement, you can ...
by bitbank
Thu Jul 06, 2017 3:07 am
Forum: C/C++
Topic: [SOLVED] Pi Zero W+SDL2 really slow app
Replies: 3
Views: 1287

Re: Pi Zero W+SDL2 really slow app

SDL2 likely won't work on a Pi0 due to the limited memory (512MB, of which at least 32MB is shared to your GPU, 64MB default) Does the Pi0 support Hardware Acceleration? One program I use on my Pi3B requires HW acceleration to run python scripts that make use of SDL2 and PyGame_SDL2 The opengl driv...
by bitbank
Wed Jul 05, 2017 9:50 pm
Forum: Gaming
Topic: Are they any game emulators that run in windowed mode?
Replies: 4
Views: 1142

Re: Are they any game emulators that run in windowed mode?

You can add SmartGear (my multi-system game emulator) to your list of games that can run in a window on the Pi desktop. I use SDL2 and GTK+3. With SDL2 and a "streaming" texture, I can get 60fps updates in a scaled window. This only works reliably now that the new opengl driver has been released wit...
by bitbank
Mon Jul 03, 2017 9:15 pm
Forum: Beginners
Topic: How do I connect an 8 bit parallel display?
Replies: 7
Views: 2560

Re: How do I connect an 8 bit parallel display?

You won't be able to use the DSI connector. That is only compatible with the official Raspberry Pi display. You will probably need to make a custom interface which connects the display ribbon cable to some of the GPIO pins. Then you will need to locate, or write, some driver software for it. Yeah I...
by bitbank
Sun Jul 02, 2017 1:33 pm
Forum: General discussion
Topic: Need information about royalties
Replies: 10
Views: 1845

Re: Need information about royalties

noob426 wrote:Hi need information i am planning to make products based on raspberry pi as a start-up do i have to
Pay any royalty for raspberry will there is any problems for in selling online
Can you share any info about what products you plan to make?
by bitbank
Sun Jul 02, 2017 1:29 pm
Forum: General discussion
Topic: High Speed Data Acquisition
Replies: 4
Views: 1252

Re: High Speed Data Acquisition

It sounds like your project would be at the upper limits of a Raspberry Pi's capabilities due to the sample rate. If you're capturing 1M 16-bit samples per second, you would likely have hiccups in the timing due to writing the data to disk and background processes interrupting your capture loop. Lin...
by bitbank
Sun Jul 02, 2017 1:24 pm
Forum: Beginners
Topic: How do I connect an 8 bit parallel display?
Replies: 7
Views: 2560

Re: How do I connect an 8 bit parallel display?

The GPIO lines are built into the RPi; no need for extra hardware. As long as your display uses 3v TTL levels, you can just wire it directly to the RPi. It then just becomes a software problem :)
by bitbank
Sun Jul 02, 2017 12:05 am
Forum: Beginners
Topic: How do I connect an 8 bit parallel display?
Replies: 7
Views: 2560

Re: How do I connect an 8 bit parallel display?

That's a pretty neat display. Do you know what price they accept for small quantities? A RPi0 or RPi3 can talk to that display using a "bit-banging" technique. You'll need to use at least 12 GPIO lines (8 data + clk + chip-select + R/W + D/C). You write all of the data pins, then toggle the clock pi...
by bitbank
Fri Jun 30, 2017 1:51 am
Forum: Gaming
Topic: *NEW* - ILI9341(240x320 LCD) Library designed for gaming
Replies: 7
Views: 4654

Re: *NEW* - ILI9341(240x320 LCD) Library designed for gaming

I'm now working with Shea Silverman and his PiPlay Portable project. The latest version of my emulator with an ili9341 on the PiPlay portable is looking pretty good. Very low latency and the usability is improving steadily. I'll keep updating here with news. Here's a video of the latest board runnin...
by bitbank
Wed Jun 28, 2017 2:29 pm
Forum: General discussion
Topic: High Speed Data Acquisition
Replies: 4
Views: 1252

Re: High Speed Data Acquisition

What kind of samples? TTL level? Analog? Multi-bit digital?

More info please.

Go to advanced search