Hi folks,

I have about 20 Keil MCB2300 boards with an LPC2378 on them. Of these,
15 seem to be running our application software with no problems at all.
The remainder consistently (some right away, others after a short amount
of uptime) exhibit significant ethernet packet loss-- around 6-10% when
doing a flood ping.) The "good" boards drop packets at well under 0.01%:
about what I'd expect from a private switched ethernet and comparable to
my desktop.

This seems to indicate one of two possible problems:

1. There is a hardware problem affecting some fraction of the
MCB2300's. It could be a problem with the PHY, MCU, PCB, or even assembly.

2. I am doing something that is pushing the parts near or beyond some
limit they have, and with 20 boards, I'm seeing the failure cases that
would result from doing this.

Note that these boards are running at 48MHz in order to avoid the
previously-discussed 72MHz+MAM problems affecting the LPC2378 silicon.
Setting MAMCR=0 also has no effect: the "bad" boards still drop packets.

Any ideas? Aside from the packet loss, the boards seem to be running
fine (no crashes, no obvious memory corruption). The problem is
reminiscent of the behavior when the power supply browns out (the first
thing to go is the ability to transmit packets, it seems. Not sure
whether it's the PHY or the MCU that's the limiting factor, but I'd
guess the PHY since it's a 3.3V device and would be hit by a brown out
first.). However, these boards exhibit poor behavior even when all the
power rails are good.

There's no obvious correlation between the MCU date code and good/bad
boards.

-Ed Start a New Thread

Hi!

I have the same problem. Start a New Thread

I found the solution for this problem. The problem is in PLL.
If you use 12MHz quartz, then you should set PLLCFG = 0x00000007;

Fcco = (2*M*Fin)/N, M=8, N=1 -> Fcco = 196MHz
Fcpu = 48MHz = 196MHz/4

Tell me if works, on your boards.
Borut
--- In l..., Edwin Olson wrote:
>
> Hi folks,
>
> I have about 20 Keil MCB2300 boards with an LPC2378 on them. Of
these,
> 15 seem to be running our application software with no problems at
all.
> The remainder consistently (some right away, others after a short
amount
> of uptime) exhibit significant ethernet packet loss-- around 6-10%
when
> doing a flood ping.) The "good" boards drop packets at well under
0.01%:
> about what I'd expect from a private switched ethernet and
comparable to
> my desktop.
>
> This seems to indicate one of two possible problems:
>
> 1. There is a hardware problem affecting some fraction of the
> MCB2300's. It could be a problem with the PHY, MCU, PCB, or even
assembly.
>
> 2. I am doing something that is pushing the parts near or beyond
some
> limit they have, and with 20 boards, I'm seeing the failure cases
that
> would result from doing this.
>
> Note that these boards are running at 48MHz in order to avoid the
> previously-discussed 72MHz+MAM problems affecting the LPC2378
silicon.
> Setting MAMCR=0 also has no effect: the "bad" boards still drop
packets.
>
> Any ideas? Aside from the packet loss, the boards seem to be
running
> fine (no crashes, no obvious memory corruption). The problem is
> reminiscent of the behavior when the power supply browns out (the
first
> thing to go is the ability to transmit packets, it seems. Not sure
> whether it's the PHY or the MCU that's the limiting factor, but I'd
> guess the PHY since it's a 3.3V device and would be hit by a brown
out
> first.). However, these boards exhibit poor behavior even when all
the
> power rails are good.
>
> There's no obvious correlation between the MCU date code and
good/bad
> boards.
>
> -Ed
> Start a New Thread