drgeoff
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Mon Mar 19, 2018 7:32 pm

fruitoftheloom wrote:
Mon Mar 19, 2018 4:16 pm
hippy wrote:
Mon Mar 19, 2018 3:43 pm
drgeoff wrote:
Mon Mar 19, 2018 2:18 pm

What relevance has that to the discussion on producing a B2+ by not fitting the RF block in an otherwise normal B3+? (That was where fotl posted his "upside down" comment.)
I simply answered the query you seemed to have on what fotl posted.

I imagined that others might also be wondering what was meant by what fotl had written, how anyone could fit an entire SoC upside down, and sought to clarify that for you and others.

If I misinterpreted your single "?" as questioning what fotl was meaning when you were not then I am sorry. But I interpreted it as best I could.

If you were questioning the relevancy of what fotl had written, rather than what was meant by what fotl had written, you could perhaps have made that clearer and I would have interpreted your post differently.

Actually I should of said "flipped" which was mentioned somewhere......my bad!


The relevance was comparing making a 2B out of a 3B to feasibly making a 2B+ out of a 3B+........
@fotl
I see no relevance. Can you convince me otherwise?

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fruitoftheloom
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Mon Mar 19, 2018 8:33 pm

drgeoff wrote:
Mon Mar 19, 2018 7:32 pm
fruitoftheloom wrote:
Mon Mar 19, 2018 4:16 pm
hippy wrote:
Mon Mar 19, 2018 3:43 pm

I simply answered the query you seemed to have on what fotl posted.

I imagined that others might also be wondering what was meant by what fotl had written, how anyone could fit an entire SoC upside down, and sought to clarify that for you and others.

If I misinterpreted your single "?" as questioning what fotl was meaning when you were not then I am sorry. But I interpreted it as best I could.

If you were questioning the relevancy of what fotl had written, rather than what was meant by what fotl had written, you could perhaps have made that clearer and I would have interpreted your post differently.

Actually I should of said "flipped" which was mentioned somewhere......my bad!


The relevance was comparing making a 2B out of a 3B to feasibly making a 2B+ out of a 3B+........
@fotl
I see no relevance. Can you convince me otherwise?

No one knows what changes were made to the actual mainboard, well no one outside RPT / RPF or has signed a NDA.

So until we do we will have no way of actually stating it is no-brainer to create a 2B+ from a 3B+.....


Yes Gregeric I talk a load of .................

Falls into the category of Pink Ponies...
""understanding the theoretical, but not always the end goal""

My other Devices are the ChromeBit CS10, ChromeCast & Huawei Mate 10 Pro SmartPhone

drgeoff
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Mon Mar 19, 2018 9:42 pm

fruitoftheloom wrote:
Mon Mar 19, 2018 8:33 pm
Yes Gregeric I talk a load of .................
That's something I don't dispute. :)

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fruitoftheloom
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Mon Mar 19, 2018 9:47 pm

drgeoff wrote:
Mon Mar 19, 2018 9:42 pm
fruitoftheloom wrote:
Mon Mar 19, 2018 8:33 pm
Yes Gregeric I talk a load of .................
That's something I don't dispute. :)

Yes but at least I admit it, which is more than most do..........

:roll:
""understanding the theoretical, but not always the end goal""

My other Devices are the ChromeBit CS10, ChromeCast & Huawei Mate 10 Pro SmartPhone

W. H. Heydt
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Mon Mar 19, 2018 9:58 pm

drgeoff wrote:
Mon Mar 19, 2018 7:32 pm
fruitoftheloom wrote:
Mon Mar 19, 2018 4:16 pm
Actually I should of said "flipped" which was mentioned somewhere......my bad!


The relevance was comparing making a 2B out of a 3B to feasibly making a 2B+ out of a 3B+........
@fotl
I see no relevance. Can you convince me otherwise?
Okay... The change from '2837A0 to '2837B0 is a "step change". It's a "minor" upgrade to the chip. so if the B0 stepping were to put into the old package, nobody would have noticed, absent an announcement, even though the changes to the boot ROM may have some fairly profound effects. The bigger issue here is that the actual Silicon chip has been "flipped". That is, it is in the package upside down compared to the old package. The chip has a lot of connections to the package--that ball grid array that is used to solder it to the PCB. By flipping the Silicon, the chip connections are no longer in the same places they were...at least, they aren't unless a mirror image operation was also carried out, and we have heard nothing about *that* being done.

Therefore, the assumption pretty much has to be made that the package to PCB connections are reversed in some way between the the two *package* versions (otherwise, the internal package wiring would get really, really...ugly). And that means that stuffing a '2837B0 onto a Pi2Bv1.2 PCB will not work. The connections are in the wrong places. That leads to two possible solutions, both of which are *probably* viable if the RPT wants to use them. The first is either a modified Pi3B+ PCB that doesn't connect or terminates the WiFi/BT connections or just uses a Pi3B+ PCB and doesn't even populate the WiFi/BT circuit area. The second is to have '2837B0 Silicon packed in the "old style" (that is, the one being used for the '2837A0 chip) and use that on the current Pi2Bv1.2 PCB.

The former approach would gain all the benefits of the Pi3B+ that pertain to the Pi2B (faster wired Ethernet, improved boot ROM, improved thermal management, PoE capability). The later approach would gain the improved boot ROM and perhaps a bit of a speed boost, but not much..

As I see it...is the improved boot ROM alone worth the change? I would argue that it is. Others will--obviously--differ.

drgeoff
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Mon Mar 19, 2018 10:51 pm

W. H. Heydt wrote:
Mon Mar 19, 2018 9:58 pm
And that means that stuffing a '2837B0 onto a Pi2Bv1.2 PCB will not work. The connections are in the wrong places. That leads to two possible solutions, both of which are *probably* viable if the RPT wants to use them. The first is either a modified Pi3B+ PCB that doesn't connect or terminates the WiFi/BT connections or just uses a Pi3B+ PCB and doesn't even populate the WiFi/BT circuit area. The second is to have '2837B0 Silicon packed in the "old style" (that is, the one being used for the '2837A0 chip) and use that on the current Pi2Bv1.2 PCB.

The former approach would gain all the benefits of the Pi3B+ that pertain to the Pi2B (faster wired Ethernet, improved boot ROM, improved thermal management, PoE capability). The later approach would gain the improved boot ROM and perhaps a bit of a speed boost, but not much..
The second version of the first solution (ie a 3B+ with the RF bits not fitted) is what I understand was being postulated. The die inside the 2837B0 being flipped has no bearing on that.

I'm not campaigning for or against a B2+ (however it might be fabricated) to be made available. Just would like any discussion to be based on relevant scientific and engineering facts.

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Imperf3kt
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Mon Mar 19, 2018 10:57 pm

:twisted: why not stop this silly discussion and make your own Pi2b+ from a Pi3b+?

Buy a Pi3b+, and make with the stabbing of the wifi chip or whatever you are suggesting to remove.

If you remove it without damaging the Pi, and it works, you have a "Pi2b+" at no extra research cost to the Pi foundation.
If it doesn't work, the Pi foundation didn't spend money that could be better spent on other things, on a failed niche product that will probably soon be deprecated anyway.
Stephen Hawking, rest in peace.
8 January 1942 – 14 March 2018

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davidcoton
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Mon Mar 19, 2018 11:36 pm

drgeoff wrote:
W. H. Heydt wrote:
Mon Mar 19, 2018 9:58 pm
And that means that stuffing a '2837B0 onto a Pi2Bv1.2 PCB will not work. The connections are in the wrong places. That leads to two possible solutions, both of which are *probably* viable if the RPT wants to use them. The first is either a modified Pi3B+ PCB that doesn't connect or terminates the WiFi/BT connections or just uses a Pi3B+ PCB and doesn't even populate the WiFi/BT circuit area. The second is to have '2837B0 Silicon packed in the "old style" (that is, the one being used for the '2837A0 chip) and use that on the current Pi2Bv1.2 PCB.

The former approach would gain all the benefits of the Pi3B+ that pertain to the Pi2B (faster wired Ethernet, improved boot ROM, improved thermal management, PoE capability). The later approach would gain the improved boot ROM and perhaps a bit of a speed boost, but not much..
The second version of the first solution (ie a 3B+ with the RF bits not fitted) is what I understand was being postulated. The die inside the 2837B0 being flipped has no bearing on that.

I'm not campaigning for or against a B2+ (however it might be fabricated) to be made available. Just would like any discussion to be based on relevant scientific and engineering facts.
@drgeoff: I appreciate your efforts to keep discussion focussed, however you seem to be overlooking the contribution quoted below, which led to the comments about flipping. Now can we stop this, and instead discuss how many Pink Ponies fit on a 40nm (or 28nm, or ...) trace....
W. H. Heydt wrote:
Sun Mar 18, 2018 10:11 pm
So my question becomes...What--if any--would be the implications of just manufacturing a Pi2Bv1.2 with a '2837B0 SoC instead of the earlier '2837 (unspecified stepping) one? In other words, are the two chips "pin compatible" and only require setting the pick-and-place robot to use one package instead of the other?
"If it ain't broke, fix it until it is."
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 12:41 am

davidcoton wrote:
Mon Mar 19, 2018 11:36 pm
Now can we stop this, and instead discuss how many Pink Ponies fit on a 40nm (or 28nm, or ...) trace....
As many as want to. Next question.

ejolson
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 5:24 am

W. H. Heydt wrote:
Mon Mar 19, 2018 9:58 pm
By flipping the Silicon, the chip connections are no longer in the same places they were...at least, they aren't unless a mirror image operation was also carried out, and we have heard nothing about *that* being done.
I vote for the flipping being compensated by a mirror image in the silicon. Keeping the pin outs in the same locations is almost a necessity for a legacy part. I wonder what the real story is.

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Imperf3kt
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 8:09 am

ejolson wrote:
Tue Mar 20, 2018 5:24 am
W. H. Heydt wrote:
Mon Mar 19, 2018 9:58 pm
By flipping the Silicon, the chip connections are no longer in the same places they were...at least, they aren't unless a mirror image operation was also carried out, and we have heard nothing about *that* being done.
I vote for the flipping being compensated by a mirror image in the silicon. Keeping the pin outs in the same locations is almost a necessity for a legacy part. I wonder what the real story is.
Nobody is talking about flipping the GPIO and other physical pins, they're talking about the connection between SoC and the board.

In any case, the whole point is moot. If you want a Pi2b+, rip the wifi/bluetooth chip off yourself and you're probably going to be happy enough.
Stephen Hawking, rest in peace.
8 January 1942 – 14 March 2018

LuisMateo
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 8:16 am

Hello, on the new RPI 3b+ , Is the wifi heatsink an antenna?

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bensimmo
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 8:23 am

LuisMateo wrote:
Tue Mar 20, 2018 8:16 am
Hello, on the new RPI 3b+ , Is the wifi heatsink an antenna?
The silver Raspberry bit?
That's a container to modularise it (or whatever the legal term is).
The antenna is then funny circuit bit to the left of it (with gpio pins at the top)
Made in UK near it on the topside and runs a bit under the black connector.
Turn it over and all the other text is written over it.

jamesh
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 9:46 am

OK, no more talk on the 2B+ stuff above please - this is a 3B+ thread. Start new thread if you wish, but keep it off this thread.
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TimG
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 10:19 am

ejolson wrote:
Tue Mar 20, 2018 5:24 am
I vote for the flipping being compensated by a mirror image in the silicon. Keeping the pin outs in the same locations is almost a necessity for a legacy part. I wonder what the real story is.
The components under the CPU have (roughly) the same layout as previously, so I reckon you must be right.

hippy
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 11:01 am

W. H. Heydt wrote:
Mon Mar 19, 2018 9:58 pm
The bigger issue here is that the actual Silicon chip has been "flipped". That is, it is in the package upside down compared to the old package ... By flipping the Silicon, the chip connections are no longer in the same places they were...at least, they aren't unless a mirror image operation was also carried out, and we have heard nothing about *that* being done.
The few SoC pins I did check on the 3B+ schematic seem to be in the same place as they were on the 3B so the notion of simply having 'flipped the silicon' does not seem to be correct.

Flipped and mirrored seems the most likely option to me, building layers of silicon downwards rather than upwards.

Just because they haven't said something was done does not mean it wasn't. There seems to be a lot of extrapolation as to what was done from a few throwaway comments on how better heat dissipation was achieved. We are all just guessing.

jamesh
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 12:14 pm

I believe the chip itself its pretty much exactly the same, its the packaging that has changed. ie the thin gold wires than connect the silicon to the package pins (BGA) are rerouted since the silicon is the other way up in the package.

Or something like that. Might be some metal layer changes to make that happen (easy to do), but not, I think, anything in the silicon itself (difficult to do).

Next time I see someone I'll try and find out more.
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 12:21 pm

The silicon was mirrored and the top metal layers of the wafer were altered slightly.

Bond pads (where wires would have connected) are turned into "bumps" that solder on to the chip substrate - the interposer that goes between the silicon and the PCB underneath. The top metal layers were modified to add power/ground bumps over the ARM CPUs and in a few other important places so that the path that current has to take to get to the power-hungry areas of the chip is as short as possible.

The key feature of the flip-chip design is that the parasitic inductance on the power/ground connections is much less - meaning voltage droops a lot less when under load.
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 2:20 pm

bensimmo wrote:
Tue Mar 20, 2018 8:23 am
LuisMateo wrote:
Tue Mar 20, 2018 8:16 am
Hello, on the new RPI 3b+ , Is the wifi heatsink an antenna?
The silver Raspberry bit?
That's a container to modularise it (or whatever the legal term is).
The antenna is then funny circuit bit to the left of it (with gpio pins at the top)
Made in UK near it on the topside and runs a bit under the black connector.
Turn it over and all the other text is written over it.
The antenna is the dimly seen triangle embedded in the PCB. It where there is no conductor in that particular layer. It's a "cavity antenna", just like the Pi0W.

The shiny bit is an RF shield.

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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 2:24 pm

jdb wrote:
Tue Mar 20, 2018 12:21 pm
The silicon was mirrored and the top metal layers of the wafer were altered slightly.

Bond pads (where wires would have connected) are turned into "bumps" that solder on to the chip substrate - the interposer that goes between the silicon and the PCB underneath. The top metal layers were modified to add power/ground bumps over the ARM CPUs and in a few other important places so that the path that current has to take to get to the power-hungry areas of the chip is as short as possible.

The key feature of the flip-chip design is that the parasitic inductance on the power/ground connections is much less - meaning voltage droops a lot less when under load.
Thank you for that information.

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davidcoton
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 4:11 pm

+1.
While in one sense the info is not important to users, I for one find it fascinating to discover what can and has be done.
Thank you for the work itself and for the insight.
"If it ain't broke, fix it until it is."
“Raspberry Pi is a trademark of the Raspberry Pi Foundation”
The Pink Unicorn is a symbol of commitment to sensible discussion of future versions of the Raspberry Pi ™

drgeoff
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 5:26 pm

jdb wrote:
Tue Mar 20, 2018 12:21 pm
The silicon was mirrored ...
Probably relatively quick and easy to do when the design is done with a high level tool. Long gone are the days of taping out layouts on clear plastic sheets.

_matteo
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 6:22 pm

Hi,

I'm a total noob on the subject but I've been excited by all the possible usage of the PI.

Now I want to try by myself, starting from a basic media station / retropie console.

I would like to purchase the last version of raspberry. Since it has been released a week ago and I cannot find any pre-packaged kits, what should I check to know if a case is compatible?

Thanks a lot for your support!!

Matteo

jamesh
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 6:30 pm

_matteo wrote:
Tue Mar 20, 2018 6:22 pm
Hi,

I'm a total noob on the subject but I've been excited by all the possible usage of the PI.

Now I want to try by myself, starting from a basic media station / retropie console.

I would like to purchase the last version of raspberry. Since it has been released a week ago and I cannot find any pre-packaged kits, what should I check to know if a case is compatible?

Thanks a lot for your support!!

Matteo
The official Pi case is DEFINITELY compatible! So I recommend that one!
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fruitoftheloom
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Re: New Raspberry Pi model 3B+ 1.4 GHz, 330Mbit Ethernet, 802.11ac, PoE

Tue Mar 20, 2018 6:48 pm

_matteo wrote:
Tue Mar 20, 2018 6:22 pm
Hi,

I'm a total noob on the subject but I've been excited by all the possible usage of the PI.

Now I want to try by myself, starting from a basic media station / retropie console.

I would like to purchase the last version of raspberry. Since it has been released a week ago and I cannot find any pre-packaged kits, what should I check to know if a case is compatible?

Thanks a lot for your support!!

Matteo
Why a kit ? Depending on where you reside you should be able to buy...

RPi 3B+
Official PSU
Official Case
Quality SD Card

..from one place:

https://www.raspberrypi.org/products/
""understanding the theoretical, but not always the end goal""

My other Devices are the ChromeBit CS10, ChromeCast & Huawei Mate 10 Pro SmartPhone

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