New Raspberry Pi Model B+

[rob77]

Don't forget the "original" reason for the RPi was to be a cheap little computer for kids to learn programming in Python. Stripping some of the commodity nature of a modern PC away was a tilt at a nostaligic ideal going back to the 80's.

Criticising it because the Broadcom CPU is not "open" it just a complete waste of time. I think it was chosen just because it was cheap. The Rpi is what it is. No one forces you to buy it.

So when they revise the design to address user feedback, that's a good thing.

+1   

[Richard Crowley]

The website has nice eye-candy and flash, but organization and presentation of hard facts, specs, and data is in short supply.

It's Broadcom, what'd you expect? Ask for more detailed information (e.g. GPIO rise times) and you'll be told in a very roundabout way, "no". (They'll try to play the "you don't need to know", "it's too complicated for you to know", etc. lines - these are people wanting to learn. ) Try asking harder and they'll just lock the thread. The forums are highly moderated to suppress any straying from the official line.

Well, I'm OK with the proprietary information about the internals of the Broadcom chip, but their attitude seems much more like "you don't need to know" or "it's too complicated".  If that is their attitude, then they are selling low-end toys and I am interesting in something more substantial.  Publishing more advanced and detailed information does NOT eclipse the "dumbed-down" version they publish for newbies.  But their attitude seems like "you are all just dumb users and you can't handle the adult version".  Bah!

[senso]

Wasn't the legal excuse that you could reverse engineer the chip if you had access to the datasheets.
What strikes me is that chip is/was used in consumer products, how comes no one leaked a complete or more complete that the actual released datasheets?

[amyk]

i think that would require a serious redesign - they're mounting chips one on a top of the other (CPU + RAM), so most probably a bigger RAM chip simply doesn't fit.

The RAM chips are in a standard 168-ball PoP package, they don't physically change size with capacity - only the die internally is higher density. The SoC supports 1GB so it would be easily doable - and 8Gb (1GB) parts are available, but apparently too expensive for their budget. One I could find is the NT6TL256T32AQ which is ~$10 a piece in 10k quantities.

and how the hell would you teach interfacing hardware with a standard PC ? RPi is ideal - it runs a widely known OS, has GPIO and has high-level language libraries/bindings for the IO.

Standard PCs have parallel ports, you can use those as GPIOs pretty easily - they're also specified to be 5V-tolerant.

Don't forget the "original" reason for the RPi was to be a cheap little computer for kids to learn programming in Python. Stripping some of the commodity nature of a modern PC away was a tilt at a nostaligic ideal going back to the 80's.
 
Criticising it because the Broadcom CPU is not "open" it just a complete waste of time. I think it was chosen just because it was cheap. The Rpi is what it is. No one forces you to buy it.

What's cheaper, more open, and has more available software  than an RPi? A perfectly working PC that's been throw away (people really do this). Nothing beats free, and it'll probably be a lot faster than the RPi too.

Wasn't the legal excuse that you could reverse engineer the chip if you had access to the datasheets.
What strikes me is that chip is/was used in consumer products, how comes no one leaked a complete or more complete that the actual released datasheets?

Because it's Broadcom.

[rob77]

The RAM chips are in a standard 168-ball PoP package, they don't physically change size with capacity - only the die internally is higher density. The SoC supports 1GB so it would be easily doable - and 8Gb (1GB) parts are available, but apparently too expensive for their budget. One I could find is the NT6TL256T32AQ which is ~$10 a piece in 10k quantities.

Standard PCs have parallel ports, you can use those as GPIOs pretty easily - they're also specified to be 5V-tolerant.

the $10 is a no-go and probably heat-dissipation would be a no-go as well - even if the 8Gb (1GB) chip has the same package.

today's standard PC has no parallel port anymore , and even if it had - teaching kids to interface LEDs and buttons with paralel port is not the best approach.

[bwat]

and even if it had - teaching kids to interface LEDs and buttons with paralel port is not the best approach.

Why not?

Sample code for parallel port IO:

Setup for reading

Code: [Select]

    MOV AL, 20H
    MOV DX, 37AH
    OUT DX, AL

Read a byte and load it into register AL

Code: [Select]

    MOV DX 378H
    IN AL, DX

Setup for writing

Code: [Select]

    MOV AL, 00H
    MOV DX, 37AH
    OUT DX, AL

Write the byte in register AL

Code: [Select]

    MOV DX, 378H
    MOV AL, DATA
    OUT DX, AL


[rob77]

and even if it had - teaching kids to interface LEDs and buttons with paralel port is not the best approach.

Why not?

Sample code for parallel port IO:

Setup for reading

Code: [Select]

    MOV AL, 20H
    MOV DX, 37AH
    OUT DX, AL

Read a byte and load it into register AL

Code: [Select]

    MOV DX 378H
    IN AL, DX

Setup for writing

Code: [Select]

    MOV AL, 00H
    MOV DX, 37AH
    OUT DX, AL

Write the byte in register AL

Code: [Select]

    MOV DX, 378H
    MOV AL, DATA
    OUT DX, AL


ok. congrats ! you know some assembly.

now tell me how the hell would you run than on a modern OS... probably you didn't notice... but it's 2014 here ! no MSDOS, no printer ports !

furthermore why the hell would you teach kids something what's not usable (code in assembly for a modern OS) and not available (LPT port)?

high level language and hardware suitable for the job is the way of teaching kids. a kid needs to see a result with minimal effort in order to maintain the level of interest and focus

[rolycat]

Using old PCs may be a cheap way for an individual child to learn about computer interfacing and low-level programming, but it would be a nightmare for a teacher with a classroom full of kids.

There might be plenty of PCs at school, but the IT department are unlikely to appreciate unknown and possibly destructive voltages being applied to their parallel ports, even if they still have them.

And how is a teacher supposed to manage a class with twenty different PCs at home sporting half a dozen OS variants, some with parallel ports, some without, and a bunch of kids whose parents couldn't be bothered to find them an old machine?

Even if somehow all of those problems could be overcome, parallel ports have a number of disadvantages. A selection:

• No power rail
• Only five input and four bidirectional pins
• Various pins are hardware inverted
• No A/D capability
• No I2C or SPI without bit-banging
• Tricky to access from modern versions of Windows

They can all be overcome with effort and ingenuity, but it's hardly intuitive.

PS
8086 assembler? 

[bwat]

ok. congrats ! you know some assembly.

It wasn't done to show off. It was a clear demonstration of how easy it was to manipulate the parallel port on a PC.

now tell me how the hell would you run than on a modern OS... probably you didn't notice... but it's 2014 here ! no MSDOS, no printer ports !

You don't need an OS. If your program is less than 510 bytes then you can stick it on a USB disk, reboot the machine and have the code executed. For development and debug just use BOCHS. See the file build.x86/mbr.S in the source code to this little kernel

furthermore why the hell would you teach kids something what's not usable (code in assembly for a modern OS) and not available (LPT port)?

Not useable? I've been paid good money to write assembly code. As for the printer port, please reread the original suggestion given earlier.

high level language and hardware suitable for the job is the way of teaching kids. a kid needs to see a result with minimal effort in order to maintain the level of interest and focus

I was taught 6502 assembly as a kid. We hand assembled and punched the machine code in, nibble by nibble, on a keypad then pushed the run button. Strangely we didn't lose interest or focus.

[bwat]

Using old PCs may be a cheap way for an individual child to learn about computer interfacing and low-level programming,

I think this is the point that is trying to be made. The thing is that the same machine can be used to teach a whole CS curriculum.

8086 assembler? 

If you're going to teach low-level then assembly language should be taught too IMHO. PCs are everywhere so 8086 is as good a choice as any.

[rob77]

i'm not saying it's not possible... but we're talking about teaching kids... there are few of them enjoying to go deeper and getting even more interested when things get more complicated , despite the lack of actual positive results during the process (i guess it was your case as well) , but the majority of kids are like "does it work in 10 minutes ? no ? that's boring shit, i rather try something else".

btw... when i was a kid/youngster i was coding Z80 and 8080 without using assembly - directly writing code in hex-editor ( a hex editor written by myself) just because i was able to do it and it was much faster than writing the code in assembly and then compile but i'm not expecting that everyone else is able to do it, and i'm not even suggesting to do it that way - because for the majority of people it's way too complicated to learn all the opcodes for the whole instruction set (and in fact it's waste of time to learn that).
so the fact that one person is able to do something doesn't mean that everyone should do it that way, and it definitely doesn't mean it's the right way of doing that thing...

so in fact the RPi is close to ideal for teaching kids how to interface HW - you get everything you need - a small computer with OS a highlevel language interpreter and libraries for easy manipulation of the GPIO pins. the kids are able to make a LED go blinky-blinky in 5 minutes (hook-up the RPi to a breadboard, stick in a led + resistor, write very few lines of python code and bob's your uncle), they'll see an actual result very quickly and there is a bigger chance that they'll get interested even more and dig deeper.

[rolycat]

Using old PCs may be a cheap way for an individual child to learn about computer interfacing and low-level programming,

I think this is the point that is trying to be made. The thing is that the same machine can be used to teach a whole CS curriculum.

Which 'same machine'? A PC? There are tens of thousands of variants, as I pointed out. Modern PCs are totally unsuitable for low-level work and old PCs are totally unsuitable for classroom work, as I also pointed out.

The whole reason why Eben Upton created the Raspberry Pi was because today's kids see computers as sealed boxes for accessing the internet and playing games. Very few people look at a modern laptop or tablet and think "Hey, I could reprogram that to control a bunch of LEDs". And kids see old PCs for what they are: yesterday's obsolete technology. They're not interested.

8086 assembler? 

If you're going to teach low-level then assembly language should be taught too IMHO. PCs are everywhere so 8086 is as good a choice as any.

high level language and hardware suitable for the job is the way of teaching kids. a kid needs to see a result with minimal effort in order to maintain the level of interest and focus

I was taught 6502 assembly as a kid. We hand assembled and punched the machine code in, nibble by nibble, on a keypad then pushed the run button. Strangely we didn't lose interest or focus.

Yeah, and Space Invaders was a craze in the 1970s. Try getting a modern kid excited about some crude pixelated blobs going bleep bleep bloop. (Unless they programmed the blobs themselves).

Times change, and education has to change with them.

[bwat]

Which 'same machine'? A PC? There are tens of thousands of variants, as I pointed out. Modern PCs are totally unsuitable for low-level work

No they're not. I develop my operating systems on modern PCs. I think they're quite suitable for low level work.

and old PCs are totally unsuitable for classroom work, as I also pointed out.

And I wrote that this wasn't the point being made. I was talking about the "individual child" as you put it.

The whole reason why Eben Upton created the Raspberry Pi was because today's kids see computers as sealed boxes for accessing the internet and playing games. Very few people look at a modern laptop or tablet and think "Hey, I could reprogram that to control a bunch of LEDs". And kids see old PCs for what they are: yesterday's obsolete technology. They're not interested.

Do you think this worked? The raspberry pi and the blinkenlights-for-the-kids marketing is part of the problem.

Times change, and education has to change with them.

Things have gotten worse. There was a time when the focus wasn't learning to program but programming to learn, as described in these books:
Mindstorms, Papert
Turtle Geometry, Abelson and DiSessa

Just look how computers were being used in education back in London:
http://link.springer.com/article/10.1007/BF01908616#page-1
http://books.google.se/books?id=oqqoUMj9-pUC&pg=PA527&lpg=PA527&dq=imperial+college+prolog+schools&source=bl&ots=j2Gi4s7CCC&sig=vyO4MnTfXG5WZYNmXWRydHQYtIc&hl=sv&sa=X&ei=SmLOU67NGoqGywPX0oC4Cw&ved=0CDIQ6AEwAg#v=onepage&q=imperial%20college%20prolog%20schools&f=false

From the New Scientis article linked above:

one boy built a built a system containing French vocabulary as an electronic phrase book.

That's an 11 year old using a mechanical theorem prover for the Horn clause fragment of first order predicate logic to
build an electronic phrase book!

[rob77]

@bwat
i think we all got the message by now

[rolycat]

Which 'same machine'? A PC? There are tens of thousands of variants, as I pointed out. Modern PCs are totally unsuitable for low-level work

No they're not. I develop my operating systems on modern PCs. I think they're quite suitable for low level work.

The context was the education of the current generation of children, not the abstruse technological obsessions of old farts like you and me.

and old PCs are totally unsuitable for classroom work, as I also pointed out.

And I wrote that this wasn't the point being made. I was talking about the "individual child" as you put it.

Context again. Teachers cannot have a different lesson plan for each child.

The whole reason why Eben Upton created the Raspberry Pi was because today's kids see computers as sealed boxes for accessing the internet and playing games. Very few people look at a modern laptop or tablet and think "Hey, I could reprogram that to control a bunch of LEDs". And kids see old PCs for what they are: yesterday's obsolete technology. They're not interested.

Do you think this worked? The raspberry pi and the blinkenlights-for-the-kids marketing is part of the problem.

It's not really being used for formal education yet, but I think it will work better than your plan to let them all duke it out with a random collection of ancient hardware.

To a degree the foundation have been a victim of their own success - the original intention was to produce a few thousand units for enthusiasts and early adopters while they worked on a complete education package, which hasn't yet been completed.

But overall I think it's working really well for mere mortals. If you believe achievement should be hard-won even for children and complete novices you may disagree.

Times change, and education has to change with them.

Things have gotten worse. There was a time when the focus wasn't learning to program but programming to learn, as described in these books:
Mindstorms, Papert
Turtle Geometry, Abelson and DiSessa

Just look how computers were being used in education back in London:
http://link.springer.com/article/10.1007/BF01908616#page-1
http://books.google.se/books?id=oqqoUMj9-pUC&pg=PA527&lpg=PA527&dq=imperial+college+prolog+schools&source=bl&ots=j2Gi4s7CCC&sig=vyO4MnTfXG5WZYNmXWRydHQYtIc&hl=sv&sa=X&ei=SmLOU67NGoqGywPX0oC4Cw&ved=0CDIQ6AEwAg#v=onepage&q=imperial%20college%20prolog%20schools&f=false

Do you think this worked?

Before you jump to the keyboard with yet another rebuttal, consider an interesting phenomenon called the backfire effect. It's a corollary to confirmation bias and means that when strongly held beliefs are challenged, opposition makes people even more intransigent. Cogent arguments against their theory are dismissed in favour of ever wilder justifications for their obsession.

Everybody suffers from it, but when most of the world agrees on a subject and you are one of the few defenders of an unpopular view, it would be well to open your mind just a little in case you are not the contrarian genius you think you are

Before someone else does I should mention that if you open your mind too much your brain will fall out 

[Rigby]

And they could add 1GB of RAM?

No, they're already at the RAM limit.  There aren't enough pins left on the chip to address more RAM.  That Broadcom chipset can't go higher than 512MB.

[rolycat]

And they could add 1GB of RAM?

No, they're already at the RAM limit.  There aren't enough pins left on the chip to address more RAM.  That Broadcom chipset can't go higher than 512MB.

Take a look at this link (also provided by amyk above). Some way down the thread, Gert Van Loo - who is a principal engineer at Broadcom - confirmed that it will support up to 1GB:

The maximum memory size supported by the JEDEC standard for a 12x12 168 PoP memory is 8Gb (notice small b!).
...
So yes: 1Gbyte is the limit.

[JOERGG]

It is your choice, there are other options

http://en.wikipedia.org/wiki/Banana_Pi

[bwat]

Before you jump to the keyboard with yet another rebuttal, consider an interesting phenomenon called the backfire effect. It's a corollary to confirmation bias and means that when strongly held beliefs are challenged, opposition makes people even more intransigent. Cogent arguments against their theory are dismissed in favour of ever wilder justifications for their obsession.

You don't see the irony that this was written by a rapsberry pi apologist? Anyway, your tactic is as bad as that other apologist Rob77 who wrote:

@bwat
i think we all got the message by now

It's the same message: "I don't like what you're writing but I have no argument so I'll just try to force you to shut up". You're both quite "passive aggressive" as the Americans, quite excellently, put it.  You're both being weighed down by a strange form of tribalism.

Everybody suffers from it, but when most of the world agrees on a subject and you are one of the few defenders of an unpopular view, it would be well to open your mind just a little in case you are not the contrarian genius you think you are

Your stated belief that I think I'm a "contrarian genius" is an insult. Granted a mild insult but an insult none the less. I'm sorry I don't like your pet project but when criticism of it means you start insulting people, then maybe there's something wrong!

Things have gotten worse. There was a time when the focus wasn't learning to program but programming to learn, as described in these books:
Mindstorms, Papert
Turtle Geometry, Abelson and DiSessa

Just look how computers were being used in education back in London:
http://link.springer.com/article/10.1007/BF01908616#page-1
http://books.google.se/books?id=oqqoUMj9-pUC&pg=PA527&lpg=PA527&dq=imperial+college+prolog+schools&source=bl&ots=j2Gi4s7CCC&sig=vyO4MnTfXG5WZYNmXWRydHQYtIc&hl=sv&sa=X&ei=SmLOU67NGoqGywPX0oC4Cw&ved=0CDIQ6AEwAg#v=onepage&q=imperial%20college%20prolog%20schools&f=false

Do you think this worked?

Again I'll point out in the New Scientist article they write

one boy built a built a system containing French vocabulary as an electronic phrase book.

That's an 11 year old using a mechanical theorem prover for the Horn clause fragment of first order predicate logic to
build an electronic phrase book!

[ronniegogs]

Just arrived. Fresh out of box. No time to play as I am travelling for Thailand and Malaysia tonight. Will power it on next week.


Rasberry Pi B+ by

[neslekkim]

It is your choice, there are other options

http://en.wikipedia.org/wiki/Banana_Pi

don't understand why one would make a clone of it, and that price?, I cant find it any cheaper than $65-70, and for that price, I would rater buy one of these:
https://www.olimex.com/Products/OLinuXino/A20/A20-OLinuXino-MICRO/open-source-hardware
https://www.olimex.com/Products/OLinuXino/A20/A20-OLinuXino-MICRO-4GB/open-source-hardware  (that I already bought)

Same cpu, but it have lots and lots of GPIO and other nice thing that is sacrified on the bananapi (and raspberry for that matter)
Have two rasberry's now, one from the very first batches of the B model (without mounting holes, and 256MB ram), and now the B+ which is an nice iteration.

[amyk]

There might be plenty of PCs at school, but the IT department are unlikely to appreciate unknown and possibly destructive voltages being applied to their parallel ports, even if they still have them.

You think RPis won't get damaged? If anything the GPIO on one is even more fragile than a parallel port. Also, a parallel port card is ~$10 or less - less than half the price of an RPi. 

And how is a teacher supposed to manage a class with twenty different PCs at home sporting half a dozen OS variants, some with parallel ports, some without, and a bunch of kids whose parents couldn't be bothered to find them an old machine?

The nice thing about PCs is that they're standardised - basic things like the addresses for parallel ports are well-known.  As for having different OSs, that can easily be solved by giving them a Linux distro to use. For your last point, what about the "bunch of kids whose parents couldn't be bothered to" buy them an RPi?

Even if somehow all of those problems could be overcome, parallel ports have a number of disadvantages. A selection:

• No power rail
• Only five input and four bidirectional pins
• Various pins are hardware inverted
• No A/D capability
• No I2C or SPI without bit-banging
• Tricky to access from modern versions of Windows

They can all be overcome with effort and ingenuity, but it's hardly intuitive.

• Power supply provides +5, +12 (and +3.3 on ATX if you want to tap into the mobo connector) volts
• The main data pins have been bidirectional since the late 80s
• So what?
• Teaching how to interface an ADC is valuable
• Bit-banging is easy enough, there are libraries to do it anyway
• Use Linux, as mentioned above, or some other low-level OS

The whole reason why Eben Upton created the Raspberry Pi was because today's kids see computers as sealed boxes for accessing the internet and playing games.

...and all he's created is another even more closed system.

Very few people look at a modern laptop or tablet and think "Hey, I could reprogram that to control a bunch of LEDs". And kids see old PCs for what they are: yesterday's obsolete technology. They're not interested.

They'll certainly be more interested if you show them what they can do with one.

[rob77]

common guys !

do you REALLY want the kids to open the PC to get 5V  from the ATX supply ? are you crazy ?

if not then please don't make statements like

Power supply provides +5, +12 (and +3.3 on ATX if you want to tap into the mobo connector) volts

and the main point.... once again... THE LPT PORT DOES NOT EXIST ANYMORE ON RECENT PCs ! that's a sheer fact and you should finally accept it !
LPT is a IT dinosaur , that's a fact. I personally like the LPT port and i still use it sometimes, but it's simply gone and we have to move forward

[tjb1]

common guys !

do you REALLY want the kids to open the PC to get 5V  from the ATX supply ? are you crazy ?

if not then please don't make statements like

Power supply provides +5, +12 (and +3.3 on ATX if you want to tap into the mobo connector) volts

and the main point.... once again... THE LPT PORT DOES NOT EXIST ANYMORE ON RECENT PCs ! that's a sheer fact and you should finally accept it !
LPT is a IT dinosaur , that's a fact. I personally like the LPT port and i still use it sometimes, but it's simply gone and we have to move forward

Eh...what?

http://www.intel.com/content/www/us/en/motherboards/desktop-motherboards/desktop-board-d525mw.html

[rob77]

Eh...what?

http://www.intel.com/content/www/us/en/motherboards/desktop-motherboards/desktop-board-d525mw.html

please ahve a look at the recent HP and Lenovo PCs (desktops, towers.. whatever)... not to mention that the popular all-in-one PCs got no LPT port from the very beginning.