BVME4000/6000
28
Copyright
1993,1995,1998,2001 BVM Ltd.
7.3.4 A24:D32
Base Address :
FD000000 or ED000000.
Size
:
16Mbyte.
Accesses to this area perform a Standard Address access to VMEbus with LWORD dependent on the
access type. Line and Long Word accesses produce a D32 (LWORD active) cycle. Word accesses
produce a D16 (LWORD inactive) cycle. Byte accesses produce a D08(EO) cycle. These accesses
involve signals on both P1 and P2, therefore, a 'P2' Backplane is required.
The following Address Modifier (AM) codes are generated:
CPU Supervisor
Program Access
=
$3E
Data Access
=
$3D
CPU User
Program Access
=
$3A
Data Access
=
$39
7.3.5 A32:D16
Base Address :
D0000000.
Size
:
16Mbyte.
Accesses to this area perform an Extended Address access to VMEbus with LWORD inactive. Line
and Long Word accesses are automatically broken down to Word (D16) cycles. Byte accesses
produce a D08(EO) cycle. These accesses involve signals on both P1 and P2, therefore, a 'P2'
Backplane is required.
The following Address Modifier (AM) codes are generated:
CPU Supervisor
Program Access
=
$0E
Data Access
=
$0D
CPU User
Program Access
=
$0A
Data Access
=
$09
7.3.6 A32:D32
Base Address
:
Immediately above the Memory Module, or 10000000 (if VMELO is
clear).
Size
:
Maximum 3328Mbyte (Memory Module Dependent).
Accesses to this area perform a Standard Address access to VMEbus with LWORD dependent on the
access type. Line and Long Word accesses produce a D32 (LWORD active) cycle. Word accesses
produce a D16 (LWORD inactive) cycle. Byte accesses produce a D08(EO) cycle. These accesses
involve signals on both P1 and P2, therefore, a 'P2' Backplane is required.
This address space can follow on contiguously from the top of a memory module, or the SRAM (if
RAMLO is set), or can be set to start at a fixed base address (if VMELO is clear). This allows for a
fixed partitioning of on-board and off-board memory for operating systems with this requirement. Refer
to "7.10 VMEbus Slave Access Controller (on page 45)" for RAMLO and VMELO settings.
The following Address Modifier (AM) codes are generated:
CPU Supervisor
Program Access
=
$0E
Data Access
=
$0D
CPU User
Program Access
=
$0A
Data Access
=
$09
