IBM 39Y6070

The IBM 39Y6070 is a NIC with a BCM5708C chip. The picture below includes two headers I soldered in.

In the top-left corner of the NIC (J334), we can access the Debug UART as shown here (again note that it doesn't come with this header):

39y6070_dbu.jpg

I used a TTL to RS232 cable (here). The settings are 192008N1, the prompt is “>” (see [1] for more info). There are 3 documented commands:

Syntax Example Description
r<addr> r145000 Read a 32-bit register value from address <addr>
d<addr> d145000 Dump 256 32-bit registers, starting at <addr>
w<addr> <data> w145000 ff Write <data> to the 32-bit register at <addr>

The best source for the register addresses is bnx2.h from the bnx2 linux driver, available here.