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Introducing Raspberry Pi B+

raspberrypi.org

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Re: Introducing Raspberry Pi B+

#201

Post by xavierxf »

weland wrote: post #133
girvo wrote: post #96

Earlier quoted context omitted.

This is something I'm very interested in, and nearly bought a Pi today; I want a board that I can learn ARM assembly and C on to build a toy OS. I built half of a tiny kernel on X86 (woo real-mode!) nearly a decade ago, so I know a tiny bit about it all, but I'd assumed the Pi was a great target: well priced, tonnes of them out there so hopefully well documented, etc. What would you suggest instead? I'm considering j…

Basically what userbinator said. I had to deal with them before, so if you can, stay away from cheap Chinese boards or hackable routers. When you're just learning, it's not worth it, the dollars you save will be more than made up in working around subtle bugs and trying to figure out what the poorly-worded, incomplete documentation is trying to convey. I also warmly suggest not to bother with anything that says Ather…

Do you, by any chance, know of a resource that documents the process of actually getting your toy OS (which I assume was cross-compiled) to run on another board such as the BBB or the RPi?

Re: Introducing Raspberry Pi B+

#202

Post by soundlab »

Does the new Compute Module share the same increased USB ports (with more power available)? Have had nagging issues prototyping Pi's with cell modems due to power consumption and was looking at the Compute for an embedded application

Re: Introducing Raspberry Pi B+

#203

Post by throwketchup »

ajross wrote: post #179
usbreply wrote: post #175

Earlier quoted context omitted.

reread the usb spec. it will not ruin the USB port.

I'm not aware of any spec requirements for overcurrent protection on the host ports (devices have strict power behavior per spec), though they may be there. I am aware, however, of countless USB host designs that simply put a 5v regulator rail on the power line and could probably be induced to overheat by a misbehaving device.

It's definitely in the USB 1.1 spec, (with some verbiage that excessive current draw on one port is not allowed to affect other ports) though they may have relaxed it later. I have several old Belkin hubs that will terminate (with prejudice) power to any port that draws over 550 mA, until you physically power-cycle the hub. This is annoying for obvious reasons, especially on 7-port hubs with beefy power supplies, so most hub manufacturers don't do that anymore.

Re: Introducing Raspberry Pi B+

#204

Post by throwketchup »

copperx wrote: post #35

I still can't see why would anyone buy one except as one of those toys that you buy and then gets tossed in the closet. 10 years ago I could see the appeal, but now? The robotics, home automation, and weekend project use cases seem like would be better served by a $5 microcontroller. Some projects, such as the weather station, justify the use of a full-fledged OS, but with the cost of buying an existing, proven, weat…

It's a valid question, not sure why you're being down voted. It nicely fills the use case of "I could totally run this project from an 80 cent microcontroller, except that it needs network connectivity, and the only practical way to do that in my environment is with 802.11 or 802.3."

The Raspberry Pi designers made a bunch of, IMHO, totally bone-headed design decisions early on (e.g., RTC "costs too much", but let's throw on a bunch of expensive ZIF connectors for overpriced peripherals that nobody will use) and the B+ is a move in the right direction to fix that.

My use case is "wifi terminal server." Which is to say that I built a battery-powered RPi system to connect Sky Safari on my iPad to a go-to telescope. The official Sky Safari wifi peripheral is $180 and can't even act as an access point! With the RPi, I have a better uart bridge (in that it runs hostapd) for one third the cost of the official solution. Plus, there is the possibility of adding auto-guiding using the gpio pins and some hacking.

Re: Introducing Raspberry Pi B+

#206

Post by alkonaut »

samirmenon wrote: post #176
alkonaut wrote: post #164

A dedicated digital audio jack would be a useful addition, it could even take the place of the useless composite video RCA, so the port arrangement of the Model B would be kept. With a digital audio jack a pi could be a decent hifi music streamer, better and cheaper than the AirPort Express. Now you need a $30-50 splitter (or the hifiberry add on) to get the audio off the hdmi, which makes the total cost more than do…

For many people, the "useless" composite video RCA is what allows them to use the Pi. It's a great way to repurpose an old TV you have laying around.

It should be fairly simple to have a single rca jack serve both purposes and switch with a jumper.

It would be interesting to hear how many actually use the rca video.

Re: Introducing Raspberry Pi B+

#207

Post by fanf2 »

tlrobinson wrote: post #159
durin42 wrote: post #122

Earlier quoted context omitted.

The Ethernet chip is a new one tho - maybe it's a little less terrible? (No idea - my applications for the rpi don't depend on it being a speed demon on the network.)

Any recommendations for similar small/cheap devices with better Ethernet?

Have a look at the Beaglebone Black.

Re: Introducing Raspberry Pi B+

#208

Post by fanf2 »

soundlab wrote: post #202

Does the new Compute Module share the same increased USB ports (with more power available)? Have had nagging issues prototyping Pi's with cell modems due to power consumption and was looking at the Compute for an embedded application

The compute module itself does not include a USB/Ethernet chip, so only has the BCM's single USB.

Re: Introducing Raspberry Pi B+

#209

Post by voltagex_ »

oasisbob wrote: post #165
gnaffle wrote: post #109

Earlier quoted context omitted.

My biggest gripe with the Pi is a lack of proper USB power, so if you add all the stuff you need, especially for a wireless setup it's not so cheap and compact anymore. I'm happy that they've (hopefully) fixed the USB power problem, that makes it much nicer as a platform.

I've been providing power over the GPIO header directly, and have had great results. Combine a DC-DC supply with a few smoothing capacitors on a small daughter-board, add a barrel jack + 0.1" headers to interface and you get a lot more headroom and flexibility with how you power it. (Same-ish end result as the other fuse bypass methods, but with no soldering on the pi, and the caps seem to help with the inrush curren…

Do you know of anywhere I can buy this ready-made?

Re: Introducing Raspberry Pi B+

#210

Post by gnyman »

oasisbob wrote: post #167
gnyman wrote: post #142

Earlier quoted context omitted.

Have you tried another power supply? I used a "high quality" one from RS (I think) and had odd problems with disk corruption and crashes when pushing the limits. I switched to a old iPad charger and the crashing problems went away.

There is a nasty bug with overclocking and filesystem corruption that is especially easy to hit under low-power conditions. Not sure if it's been fully fixed. eg: http://www.raspberrypi.org/forums/viewtopic.php?f=29&t=26633

Thanks I did not know, I believe I had it overclocked at the time. Very useful to know about if it starts happening more often.
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