Specifications

Registers
F F
F-5
VME A21-16 Address Register (8130)
VMEbus Address bits 21-16 1 1
When an access is performed by the EPC-8 in its "E page" (address range 0E0000-
0EFFFF), the access is mapped onto the VMEbus. The least-significant sixteen of the
VME address bits are provided directly (from the 486), and the remaining 8 (for an
A24 access) or 16 (for an A32 access) bits must come from somewhere else. Six of
them come from this register. Bit 7 of this register is used as VME address bit 21, bit
6 as VME address bit 20, ..., and bit 2 as VME address bit 16.
The two low-order bits are ROM bits. For compatibility with older EPC's, this
register is aliased at I/O port addresses 8132, 8134, and 8136.
ID Register (8140 & 8141)
1 1 1 0 1 1 0 0 Lower
1 0 1 1 1 1 1 1 Upper
This read-only register adheres to the VXIbus specification. It defines the EPC-8 as a
message-based device and the manufacturer as RadiSys Corporation.
Device Type Register (8142 & 8143)
1 1 0 0 0 1 0 0 Lower
0 0 0 0 0 0 0 S Upper
This register adheres to the VXIbus specification. The value defines the EPC-8 as
having a model code of 0C4h if it is a slot 0 controller and 1C4h if it is not a slot 0
controller). Note that the S bit is a read/write bit that is configured by BIOS very early
in the boot sequence. This bit may also be read/written from the VME port as well.
Status/Control Register (8144 & 8145)
SRIE 1 SYSC 1 READY PASS NOSF SRST Lower
0 MODID SYSR R RESDET 1 1 1 Upper
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com