Specifications

Chapter 4: Theory of operation
61
Slot of the CompactPCI chassis.
RTM_P Indicates that a Rear Transition Module is installed. It is an active low
signal. If zero it indicates that the RTM for the CPU is present in the
system.
INTS_IN Routes CompactPCI interrupts to the processor. If set to one the CPU
receives ~INTA , ~INTB, ~INTC, and ~INTD from the CompactPCI
backplane.
GA4:0 The CompactPCI Geographical Address pins from the CompactPCI
backplane. They are used to determined which CompactPCI slot the CPU
is in.
BIOS bank switching
The CPU Board has eight pages of Flash at the top of memory. Each page is 512k
bytes, in an 8-bit format. One of the pages, the PC BIOS page, has a boot block
architecture. The remaining seven pages are made from an Intel Strata Flash. The
BIOS control Register in the CPLD controls which page is active. On initial power-
up, the BIOS Control Register will be set to point at the top of the boot block flash,
where the PC BIOS resides. At some time later, software can select one of the other
seven banks to execute from. The BIOS Control Register will be reset on all reset
Table 4-11. CompactPCI geographical address
Slot number GA4 GA3 GA2 GA1 GA0
000000
100001
200010
300011
400100
500101
600110
700111
801000
901001
10 01010
11 01011
12 01100
13 01101
14 01110
15 01111