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by CapnBry
Wed Feb 04, 2015 3:32 am
Forum: Advanced users
Topic: Linux kernel is now 3.18
Replies: 68
Views: 27084

Re: Linux kernel is now 3.18

I'm having issues with the 3.18 kernel on a B+ with an FTDI FT231X USB UART device. It simply stops receiving data after anywhere from 5 seconds to at most 60 seconds. $ stty -F /dev/ttyUSB0 38400 raw $ cat /dev/ttyUSB0 ..data for a few seconds... If I hit Ctrl-C and then restart it, it works for a ...
by CapnBry
Wed Feb 04, 2015 2:30 am
Forum: General discussion
Topic: Where to buy the old RaspberryPi models A or B ?
Replies: 35
Views: 5390

Re: Where to buy the old RaspberryPi models A or B ?

I'm in the same boat with a project based on the Model A/B that doesn't mate with the B+. I tried ordering 100 Model Bs from Newark/element14 back in November (at full $35 price) but they canceled the order and told me they weren't getting any more stock. I tried to buy all 83 they had and they said...
by CapnBry
Wed Apr 03, 2013 1:54 pm
Forum: General discussion
Topic: Allied Electronics - hidden postage charges
Replies: 21
Views: 6640

Re: Allied Electronics - hidden postage charges

It is common practice for parts suppliers to calculate shipping at the time of shipping and not when you place an order. That's your indicator that you should try and guess what the cheapest method of shipping is and go with that rather than the "I need it now!" impulse we're used to with retailers ...
by CapnBry
Tue Dec 11, 2012 8:24 pm
Forum: Automation, sensing and robotics
Topic: HeaterMeter: Automated BBQ and Sous-vide controller
Replies: 7
Views: 52555

Re: HeaterMeter: Automated BBQ and Sous-vide controller

What I did was just put an RCA jack on the SSR's input and then use an audio cable to connect it to the RCA on the HeaterMeter. I think it would work OK with the default settings, but better results can be achieved by setting the "Min Fan Speed" to 100% in the web interface. This changes the output ...
by CapnBry
Sat Sep 22, 2012 10:56 pm
Forum: Automation, sensing and robotics
Topic: HeaterMeter: Automated BBQ and Sous-vide controller
Replies: 7
Views: 52555

HeaterMeter: Automated BBQ and Sous-vide controller

Continuing on the success of the LinkMeter Project come the HeaterMeter v4.0 revision for RasbperryPi or standalone use. HeaterMeter for RaspberryPi joins an Arduino / AVR ATmega328 microcontroller with OpenWrt running on a RaspberryPi $35 wonder-computer for the purpose of providing oven-like contr...
by CapnBry
Sat Sep 22, 2012 10:33 pm
Forum: Automation, sensing and robotics
Topic: Powering the PI
Replies: 7
Views: 1750

Re: Powering the PI

If space is at a premium, I use a Murata OKI-78SR in my project. It runs about $4.50 each but is smaller than a TO-220 outline which makes it about 1/4th the size of one of those LM2596 boards. It needs an external capacitor though.
by CapnBry
Thu Aug 16, 2012 8:39 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ttyAMA0: 1 input overrun(s)
Replies: 17
Views: 9726

Re: ttyAMA0: 1 input overrun(s)

I couldn't get 38400 working 100% reliably so I ended up dropping down to 19200 baud to resolve the issue. When I was testing another issue with a logic analyzer on the serial lines, I noticed that echo defaulted to on. This is something else to check to see if it makes a difference: [email protected]:/#...
by CapnBry
Sun Aug 05, 2012 4:47 pm
Forum: Advanced users
Topic: Minimum FAT partition size?
Replies: 9
Views: 5856

Re: Minimum FAT partition size?

I think there must be some sort of miscommuncation, because I don't think we're talking about the same thing at all. I'm talking about the boot partition of the the RasbperryPi SD card. Yes I can mount an image using loop and modify the image, but to get the Pi to boot it it has to be on physical me...
by CapnBry
Sat Aug 04, 2012 9:01 pm
Forum: Advanced users
Topic: Minimum FAT partition size?
Replies: 9
Views: 5856

Re: Minimum FAT partition size?

Aha! You are a genius. Anything less than 8256KB gets a FAT12 filesystem. It is very possible that the bootloader only works with FAT16 (and possibly FAT32). If you force FAT16 on a smaller filesystem, the partition type must be 0x04 to indicate FAT16 with less than 65536 sectors. It still won't boo...
by CapnBry
Sat Aug 04, 2012 5:19 pm
Forum: Advanced users
Topic: Minimum FAT partition size?
Replies: 9
Views: 5856

Re: Minimum FAT partition size?

A loopback filesystem doesn't make anything smaller, it is a method of mounting a filesystem from a file rather than a device. Also, the GPU bootcode can't run from anything other than a FAT partition as far as I know. The question isn't "How do I make this smaller?" the question is "How small is to...
by CapnBry
Sat Aug 04, 2012 1:47 pm
Forum: Advanced users
Topic: Minimum FAT partition size?
Replies: 9
Views: 5856

Re: Minimum FAT partition size?

Ahh fiddlesticks. I meant to post this in the "Power Users" forum. Can a mod please move this?
by CapnBry
Sat Aug 04, 2012 1:24 pm
Forum: Advanced users
Topic: Minimum FAT partition size?
Replies: 9
Views: 5856

Minimum FAT partition size?

I'm building my own special purpose distro using OpenWrt to replace one that currently runs on Linksys WRT54GL routers and weighs in at 3.25MB. Because I don't have infinite bandwidth, I'm trying to get the system down as small as possible. The kernel and rPi firmware boot files on the first partiti...
by CapnBry
Wed Aug 01, 2012 2:56 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ttyAMA0: 1 input overrun(s)
Replies: 17
Views: 9726

Re: ttyAMA0: 1 input overrun(s)

Actually it is happening on my second rPi which is only connected via ethernet as well so I think it might be something in the underlying infrastructure that just gets worse when there's also a USB wifi device thrown in the mix. Hopefully as the kernel matures, this will be solved. My work around wa...
by CapnBry
Tue Jul 31, 2012 6:44 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ttyAMA0: 1 input overrun(s)
Replies: 17
Views: 9726

Re: ttyAMA0: 1 input overrun(s)

I got excited and spoke too soon, tons of errors overnight. I also checked my ethernet-only Pi and it also had errors in the log so it isn't limited to just the one with wifi. Is anyone else doing long-duration UART transfers and actually doing some sort of checksum checks? I'm not sure where else t...
by CapnBry
Mon Jul 30, 2012 10:32 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ttyAMA0: 1 input overrun(s)
Replies: 17
Views: 9726

Re: ttyAMA0: 1 input overrun(s)

This may be yet another power-related problem. I tried all the 1A-2A wall warts I had around the house from tablet chargers to phone chargers and was only getting anywhere from 4.4V to 4.6V. I switch to using my custom daughterboard's power supply (one of those Murata 5V 1.5A switching power supplie...
by CapnBry
Mon Jul 30, 2012 10:21 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: low power wifi modules
Replies: 5
Views: 3830

Re: low power wifi modules

If it is like the other wifi modules that look identical to that, it is probably based on the Realtek 8192cu chip. Full source code for the module (except the firmware which is a blob) is available so you can hack to your heart's content. I don't have any power usage data for you but it is also used...
by CapnBry
Mon Jul 30, 2012 8:39 pm
Forum: General discussion
Topic: An nbench challenge
Replies: 32
Views: 11531

Re: An nbench challenge

After a day of running the ASSIGNMENT test and not completing, I began to suspect it may not every complete. I looked back at the source code and found a problem for folks like me who are cross-compiling on x86-64 bit hosts. The make process does a test for 64-bit long on the host system (see pointe...
by CapnBry
Sun Jul 29, 2012 5:59 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Linux/C: Set baudrate before opening serial/UART; Servo
Replies: 13
Views: 20994

Re: Linux/C: Set baudrate before opening serial/UART; Servo

That's awesome! I'm glad you found the problem. I try to be as polite as possible to people who know what they're doing programming-wise because it's easy to come off sounding insulting when you supply a somewhat obvious solution. When you're done with your project, whatever it is, make sure you pos...
by CapnBry
Sun Jul 29, 2012 5:05 pm
Forum: General discussion
Topic: An nbench challenge
Replies: 32
Views: 11531

Re: An nbench challenge

For kicks I decided to make an nbench-byte package for OpenWrt and see how my numbers compare to the best results so far. My openwrt builds (gcc 4.6 linaro) with -march=armv6 -mtune=arm1176jzf-s -mfpu=vfp -mfloat-abi=softfp -marm This is hilarious because nbench has been running for an hour now and ...
by CapnBry
Sun Jul 29, 2012 2:35 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Linux/C: Set baudrate before opening serial/UART; Servo
Replies: 13
Views: 20994

Re: Linux/C: Set baudrate before opening serial/UART; Servo

Oh nice, you've obviously done your homework on this! It looks like you've got a good command line that doesn't mess up the baud detection on the servo controller. This is just a shot in the dark, and I hope it isn't insulting, but you're not trying to set the baud rate directly in the cfsetospeed()...
by CapnBry
Sun Jul 29, 2012 12:16 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Linux/C: Set baudrate before opening serial/UART; Servo
Replies: 13
Views: 20994

Re: Linux/C: Set baudrate before opening serial/UART; Servo

The Pololu serial device haven't any experience with, but I do have a lot of experience with serial communication under Linux so maybe I can provide some insight into that. When you open() a serial device, no data is transmitted. Serial is known as "asynchronous communication" in that the first bit ...
by CapnBry
Sat Jul 28, 2012 11:58 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ttyAMA0: 1 input overrun(s)
Replies: 17
Views: 9726

ttyAMA0: 1 input overrun(s)

I've spent all day today getting the downloaded-from-the-realtek-site rt8192cu driver working in nl80211 mode (wext is for script kiddies!) and configurable under OpenWrt's web interface. However, once the driver is loaded, the UART on the Pi starts behaving badly, dropping data that is coming in on...
by CapnBry
Thu Jul 12, 2012 8:53 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Possible to leave SPI CE0 low between transmissions?
Replies: 4
Views: 3429

Re: Possible to leave SPI CE0 low between transmissions?

I'll tell ya though, programming a 32KB ATmega over the SPI bus is the way to go. The datasheet says the SPI clock needs to be high and low for 3 clocks each which gives you an 2MHz SPI bus for a 16MHz CPU. Flashing 32KB takes about 3 seconds (most time is spinning waiting for flash page writes to c...
by CapnBry
Thu Jul 12, 2012 4:07 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Possible to leave SPI CE0 low between transmissions?
Replies: 4
Views: 3429

Re: Possible to leave SPI CE0 low between transmissions?

I was under the impression that the ioctl was a synchronous call and it wouldn't return until the messages had been transmitted. I have no way of easily measuring that but it is a bit of a moot point because I can't rely on being able to keep the any sort of buffer full enough of data that I can't g...
by CapnBry
Thu Jul 12, 2012 1:29 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Possible to leave SPI CE0 low between transmissions?
Replies: 4
Views: 3429

Possible to leave SPI CE0 low between transmissions?

I've written an application that uses bootc's SPI driver to program an ATmega328 chip over the RPi's SPI bus. I had decided to use the CS line to hold the AVR in /RESET during the conversation. However, the SPI driver only keeps CE0 low while writing, or during the delay_usecs delay included with th...

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