Motorola MVME197LE user manual

Memory Maps

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.

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];

}

The fields are defined as follows:

1.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

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

000000470476

3.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.)

3

MVME197LE/D2 3-25