[rbak-nsp] PPA2 memory organization

[Marcin Kuczera]

Marcin Kuczera wrote:
> hello,
> 
> I have to repair SE100 (it is a plague of PPA memory faults..)
> 
> I was trying to discover memory organization of PPA2.
> In SE100 each PPA has:
> - 8x 32M16 chips (so 265MB of 16Bytes words)
> - 4x 32M8 chips (so 128MB of 8Bytes words)
> (if there are some chips on the bottom of PCB, then more (x2), but I 
> haven't check it yet).
> 
> Now, I suppose that one is for FIB, the other - packet memory.
> I would say, that smaller (128MB) is for packet contents, larger for FIB.
> 
> In diagnostics report, there are 2 memory reports related to single PPA:
> IPPA Memory
> IPPA SRAM Mem Test
> 
> Anyone knows which is which ?
> If fiest fails, should I repair 128Mx8 or 256Mx16 ??

Well, no answers, but I have some update.
There is 2x more of memory than I though, there are also chips on the 
bottom of PCB.

It looks that:
- there is 1GB (or 512k x 16) of FIB/ACL memory for each PPA
- there is 256MB of packet buffers for each PPA

And - it is not a problem of memory, it is a BGA fault of PPAs..
So, next week we will try reballing of both iPPA and ePPA.

btw, anyone knows if first SE100 were assembled using RoHS or not ?


Regards,
Marcin