External Register Set - Motorola MVME2600 Series Reference Manual

Falcon ECC Memory Controller Chip Set

External Register Set

ADDRESS
3 BIT
NAME
OPERATIO
N
RESET
3-54
$FEF88000 - $FEF8FFF8
EXTERNAL REGISTER SET
EXTERNAL REGISTER SET
The EXTERNAL REGISTER SET is user provided and
is external to the Falcon pair. The Falcon pair provides a
static RAM style interface for the external registers. The
external registers can be SRAM, ROM, Flash or some
other user device. There can be one device connected to
either the upper or lower Falcon, or there can be two
devices with one connected to each Falcon. The devices
can be 8, 16, or 32 bits wide. The data path to the external
devices is via the RD32-RD63 pins. Reads to the external
devices can be any size except burst. Note that if the
devices are less than 32 bits wide, reads to unused data
lanes will yield undefined data. Note that writes are
restricted to one or 4-byte length only. 4-byte writes can
be used for any size device, data should be placed on the
correct portion of the data bus so that valid data is written
to the device. Data duplication is turned off for the
EXTERNAL REGISTER SET so writes can be to either
the upper Falcon, or to the lower Falcon.
Note
For descriptions of how these registers are used in the
MVME2600/2700 series boards, refer to the Falcon-
Controlled System Registers in Chapter 1, especially the
System External Cache Control Register and the CPU
Control Register.
READ/WRITE
X PL