user manual

Memory Maps
3-5
3
Notes:
1. Flash/EPROM devices appear at $FF800000 through $FFBFFFFF,
and also appear at $00000000 through $003FFFFF if the ROM0 bit in
the VMEchip2 EPROM control register is high (ROM0 = 1). The
ROM0 bit is located at address $FFF40030 bit 20. ROM0 is set to 1
after each reset. The ROM0 bit must be cleared before other
resources (DRAM or SRAM) can be mapped in this range
($00000000 through $003FFFFF). The VMEchip2 and DRAM map
decoders are disabled by a local bus reset.
On the MVME177, the Flash/EPROM memory is mapped at
$00000000 through $003FFFFF by hardware default through the
VMEchip2.
Table 3-1. Local Bus Memory Map
Address
Range Devices Accessed Port Size Size
Software
Cache
Inhibit Notes
$00000000 -
DRAMSIZE
User programmable
(onboard ECC DRAM on
mezzanine)
D32 DRAMSIZE N 1, 2
DRAMSIZE -
$FF7FFFFF
User programmable
(VMEbus A32/A24)
D32/D16 3GB - 3, 4
$FF800000 -
$FFBFFFFF
EPROM/Flash D32 1MB
EPROM/
4MB Flash
N1
$FFC00000 -
$FFDFFFFF
Reserved -- 2MB -- 5
$FFE00000 -
$FFE1FFFF
Onboard SRAM (default) D32 128KB N 6
$FFE20000 -
$FFEFFFFF
Onboard SRAM (repeated) D32 896KB N 6
$FFF00000 -
$FFFEFFFF
Local I/O devices
(refer to next table)
D32-D8 960KB
(1MB-
64KB)
Y3
$FFFF0000 -
$FFFFFFFF
User programmable
(VMEbus A16)
D32/D16 64KB - 2, 4