Hardware manual

EUROCOM-17-5xx 3 Programmers Reference
Hardware Manual 89
The snoop control register is write only. So the user must implement some
mechanism to avoid that one CPU accidently alters the snooping mode of
the other CPU.
Snooping of the secondary CPU has to be enabled only if J1802 is set to
position 2-3. Enabling snooping of the secondary CPU with J1802 in
position 1-2 will cause erratic behavior of the secondary CPU. If only the
primary CPU is snooping, J1802 should be set to position 1-2 because
this gives better memory performance.
3.20 Revision Information
Revision information is stored on the board to give software the chance to
distinguish between different versions and derivates of the
EUROCOM-17-5xx. The information may consist of two parts. First there
are bits3-7 of the IOC-2’s control register at $FEC7.00A8.
Table54: IOC-2 Control Register at $FEC7.00A8
If bits5-7 of the ICR are %100, extended revision information is available
at the serial EEPROM.
The serial EEPROM is a 512B FRAM which is used to store ELTEC
specific board revision information. For the user, the upper 256B of the
FRAM are reserved to store additional information.
The lower 256B of the FRAM contain the extended board revision
information. These factory settings must never be modified by the
user to guarantee system consistency.
Register Address 31 - 8 7 - 5 4 3 2 - 0
ICR $FEC7.00A8 used for IOC-2
internal
purposes
0 0 0 ELTEC initial version 0 0 25MHz used for IOC-2
internal
purposes
0 0 1 EUROCOM-17-1xx/2xx 0 1 33MHz
1 0 0 EUROCOM-27-xxx
EUROCOM-17-5xx
1 0 40MHz
other reserved 1 1 reserved
i
i
!