[LAU] Raspberry PI, internal audio IF + testing new USB IF

Simon Wise simonzwise at gmail.com
Wed Mar 4 14:12:32 UTC 2015

On 05/03/15 00:22, Jeremy Jongepier wrote:
> On 03/03/2015 11:35 PM, Ken Restivo wrote:
>> After doing several Raspberry Pi projects, I'm very negative on them, and will never use them or recommend them again.
>> The built-in audio is crap, it's not even 16-bit.
> True, it's 11-bit PWM so also not your standard DAC ;)

best use for Raspberries for me has been when I want to run audio and image 
through HDMI, with some GPIO based controls connected locally with the 
networking used for set-up only, or simple networked messaging for cues ... 
mostly as multiple stand alone devices feeding projectors and speakers.

Also with a wolfson card for audio ... but that doubles the price and adds 
several complications, but also offers quite interesting opportunities I have 
only started exploring.


>> The power management and regulation is non-existent and sucks. Raspberry
>> Pi's have destroyed a half-dozen SD cards of mine. The people in the Pi
>> community just shrug about this. It's unacceptable to me.

Yes, I've lost a card, maybe two, out of maybe 25 Pis running here and there. 
Not good. And fast cards (for hi res video) cost more than the Pi.

> Bought my first RPi in the Fall of 2012 and that one, including all the
> ones that came after it, have not eaten any SD card in my case. Had my
> share of corrupted filesystems though but no faulty SD's.

>> USB is a joke on Raspberry's. I wouldn't even try to use a USB device. The
>> Raspberry developers solved this problem by doubling the number of USB
>> ports on the new B+ units... without fixing any of the problems... so now
>> you can have twice the fail.

The A+ is probably the most sensible model, the USB has worked for me for single 
audio devices, and for sensors ... it might even be better without that LAN 
chip, and for setup purposes a single USB-ethernet dongle for a whole collection 
of Pis will do it.

Don't choose a Pi if USB is your interface ... they are much better for HDMI and 
GPIO uses.

> The implementation is not that good but I can live with it.

>> Ethernet is a joke; it's a USB device. To get the Pi to work reliably, I've
>> had to turn off USB2 mode anyway, so the Ethernet is beat-the-dog slow
>> too.

It is set-up, ssh, file transfer (plus maybe simple triggering and messages via 
ethernet) for me ... see above

> If you disable Turbo mode for the ethernet interface network is a wee
> bit slower but USB performance is better.
>> There's no databook for the chip, last I checked. Oh sure, there's a PDF documenting a few of the features of the I/O ports. There's no actual databook, like any good CPU core or SOC would have.
> That's surely a major drawback.

It is the biggest disappointment for me, especially given the sales pitch. 
Freescale and others do much better than Broadcom. I've learnt a lot from the 
sample code, and working through the limitations!


>> There's no real bootloader. Some call it a feature, I don't. There's no
>> built-in flash either (another thing touted as a feature that I consider a
>> design limitation).

there are some advantages to everything being contained on the SD card, for easy 
swapping projects etc. But ... it depends.

> I call it a feature, takes away the complexity of picky bootloaders like
> uBoot. Flash memory is nice but apart from not having to buy a SD card
> for a couple of bucks I don't really see the advantage of it. On my
> Cubieboard2 I don't get any noticable performance gain when running the
> OS from flash.
>> I don't consider it economical since once you add up all the things you'll
>> need to get it to do work, you could buy a better-engineered platform for
>> the same price. And the Pi is slower than many of the other platforms in
>> its price range.

It was in its time, and it probably helped provoke the range now available ... 
having raspbian ready to go was a boon ... many others have followed now.

> The community is huge, I'd call that a valuable economical asset. But
> then I have no notion of how big the other communities are at the moment.
>> I'd instead recommend the BeagleBone Black for projects if you want a mature, well-documented platform, or any number of the new exciting ARM-based platforms coming out if you wanted to venture into something new.
>> I've done a few projects using the Pi over the past few years, both pro-bono and professionally, and I would not recommend the platform to anyone.
> The RPi is just not made for professional use. If you need an ARM
> development board for professional use I'd recommend a Beagleboard,
> Cubieboard, Odroid or any other board that doesn't have the
> aformentioned issues with the onboard audio, USB, ethernet,
> documentation etc. But then in my experience most of these alternatives
> are more expensive than a RPi.

these days the prices are quite a bit closer ... especially if you find a device 
that covers all your needs without extras and dongles. And a bit more $$ buys a 
hell of a lot more power and options.

as far as professional use ... whatever that means ... the Compute Module is 
probably more the way to go, all the pins and none of the cheap peripherals, 
probably with much better docs via NDA etc with Broadcom. Raspberries seem best 
suited to setting up for a specific use than as a general purpose device, and 
the price might work out very well in that case.

>> Sorry, I like to stay positive but my experience with Raspberry's has not been good.
> I like 'm but I can imagine people really having issues with them. I
> jumped the bandwagon not expecting much of it. So far the RPi exceeds my
> expectations for a $35 computing device.

they really expanded the number of people playing around with this scale of 
device ... that is an achievement on its own


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