Experimental Physics and
Industrial Control System

[email protected] (Ralph Lange) · Mon, 7 Jul 1997 21:20:09 +0200 (METDST)

Hi Andrew,

> [...]
> The SPECIAL CONSIDERATIONS section of the vxWorks BSP
> man page 'mv167' explains how to set the clock rate in the non-volatile
> RAM, which you do once for each CPU card. Just type the following at the
> vxWorks shell prompt:
>   -> m 0xfffc00fe
>   fffc00fe:  0000-21ee
>   fffc0100:  0000-.   

We only use mv162's, the clock rate is not mentioned on the "mv162" man
page, the memory location you suggested seems to be unused on the
mv162.

What I do to detect the CPU speed is check four bytes within the
"Configuration Area" of the NVRAM at address 0xfffc1f28 which read
0x32353030 (ASCII "2500") for 25MHz and 0x33323030 (ASCII "3200") for 32MHz
boards - I checked this on the MV162-042 (25MHz) and the MV162-532 (32MHz).
I do use different values for SYS_CPU_FREQ in the VxWorks configuration
config/mv162/config.h depending on the board version, so maybe this is
written into the NVRAM at boot time.

Does VxWorks keep its own copy of the CPU speed value? Does my method work
on mv167's, too? What does 0x21ee stand for? Should I use sysNvRamGet() to
stay board independent?

Confused,
Ralph

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System