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Hi,

How does the XAM3359AZCZ on the initial run of beaglebone compare to AM3358BZCZ100 which would feature on the final runs ?

What are the feature differences ? and why is this processor switch being done ?

--

Kunal

Kunal Ghosh wrote:

 

How does the XAM3359AZCZ on the initial run of beaglebone compare to AM3358BZCZ100 which would feature on the final runs ?

What are the feature differences ? and why is this processor switch being done ?

I'm not a TI employee or representative, but I believe the A->B means that the silicon revision has gone from 2.0 to 2.1.  According to TI's Silicon Errata document, the only behavioral change is improved latch-up.  The "100" is the important part -- it's now a 1 GHz part.  The initial "X" means it's an "experimental" part rather than a fully-qualified device, i.e., you get to be a pioneer

what about the 9->8 in 3359A -> 3358B? 

and what is the DDR3 clock speed?

I've seen 300MHz, 400MHz, 600MHz, and 800MHz.

coder27 wrote:

 

what about the 9->8 in 3359A -> 3358B? 

The PRUSS can't do EtherCAT, which is a form of pass-through switching between Ethernet ports so you don't have to store and forward complete frames.  Since there's only one Ethernet port on BeagleBone, it's not worth paying extra for EtherCAT.  I don't know any details -- I just looked up EtherCAT myself.

coder27 wrote:

and what is the DDR3 clock speed?

I've seen 300MHz, 400MHz, 600MHz, and 800MHz.

I'd suggest grabbing a copy of the SRM from

http://circuitco.com/support/index.php?title=BeagleBoneBlack#LATEST_PRODUCTION_FILES_.28A5A.29

it lists the DDR3L as running at 606Mhz (303Mhz base clock). Quite why the slightly odd frequency I don't know, but I'm sure there will be a reason.

The SRM will answer all the basic hardware questions, but you'll probably need individual datasheets for the real details.

Hi John, by PRUSS were you referring to -> http://processors.wiki.ti.com/index.php/Programmable_Realtime_Unit_Subsystem ?

Quite an insight ( I am completely new to all of this ) . Does the "X" usually (by most manufacturers) refer to experimental ?

I went through the BeagleBoneBlack system reference manual, as suggested by selsinork, and it atleast made one thing clear:

"We do not expect any benefit from moving to this device and there should be no impact seen as a result of making this move."

So, the early adopter wouldn't be at a loss when Circuitco decides to move to the newer chip

Kunal Ghosh wrote:

 

Hi John, by PRUSS were you referring to -> http://processors.wiki.ti.com/index.php/Programmable_Realtime_Unit_Subsystem ?

Yes.  PRUSS is one of those nice acronyms that doesn't have many meanings like IP or PCI.

Kunal Ghosh wrote:

 

Quite an insight ( I am completely new to all of this ) . Does the "X" usually (by most manufacturers) refer to experimental?

Many manufacturers use a designation like this for "preproduction" chips.  Generally they're functionally correct, but they may not meet all the timing and electrical parameters over the full temperature and voltage range.  Since chips vary between fabrication runs, it takes a while before you really have a full picture of how they're going to perform under all conditions.  The manufacturer may need to tweak the timing specs or tweak the process to make chips that match the data sheets.

The "X" parts let designers get started using actual chips.  We generally are using accurate power supplies and running everything at room temperature, so if the chip doesn't work properly at 85C and 3.0V we're not going to notice during development.  We hope that the fully qualified chip is ready by the time we need it for full temperature range testing and for production.

Kunal Ghosh wrote:

 

Quite an insight ( I am completely new to all of this ) . Does the "X" usually (by most manufacturers) refer to experimental?

Many manufacturers use a designation like this for "preproduction" chips.  Generally they're functionally correct, but they may not meet all the timing and electrical parameters over the full temperature and voltage range.  Since chips vary between fabrication runs, it takes a while before you really have a full picture of how they're going to perform under all conditions.  The manufacturer may need to tweak the timing specs or tweak the process to make chips that match the data sheets.

The "X" parts let designers get started using actual chips.  We generally are using accurate power supplies and running everything at room temperature, so if the chip doesn't work properly at 85C and 3.0V we're not going to notice during development.  We hope that the fully qualified chip is ready by the time we need it for full temperature range testing and for production.