Bbram, tod clock memory map – Motorola MVME197LE User Manual

Page 55

Memory Maps

MVME197LE/D2

3-25

BBRAM, TOD Clock Memory Map

The MK48T08 BBRAM (also called Non-Volatile RAM or NVRAM) is divided
into six areas as shown in Table 3-12. The first five areas are defined by
software, while the sixth area, the time-of-day (TOD) clock, is defined by the
chip hardware. The first area is reserved for user data. The second area is used
by Motorola networking software. The third area is used by the SYSTEM V/88
operating system. The fourth area is used by the MVME197 board debugger.
The fifth area, detailed in Table 3-13, is the configuration area. The sixth area,
the TOD clock, detailed in Table 3-14, is defined by the chip hardware.

The data structure of the configuration bytes starts at $FFFC1EF8 and is as
follows.

The fields are defined as follows:

Four bytes are reserved for the revision or version of this structure. This
revision is stored in ASCII format, with the first two bytes being the major
version numbers and the last two bytes being the minor version numbers.
For example, if the version of a structure is 4.6, this field contains:

0460

Twelve bytes are reserved for the serial number of the board in ASCII
format. For example, this field could contain:

000000470476

Sixteen bytes are reserved for the board ID in ASCII format. For example,
for a MVME197LE module, this field contains:

MVME197LE

(The nine characters are followed by seven blanks.)

struct config_rom {

char

version[4];

char

serial[12];

char

id[16];

char

pwa[16];

char

speed[4];

char

ethernet_adr[8];

char

reserved[195];

char

cksum[1];

}