System Memory; Interrupt Controller - NEC POWERMATE 4100M Service Manual

Address (Hex)
3D0-3DF
3F0-3F7
3F8-3FF

System Memory

The PowerMate 433D, 466D, and 466M system boards come standard with 4 MB of RAM.
The PowerMate 4100M system board comes standard with 8 MB of RAM. The first mega-
byte includes the standard 640 KB of base memory. The remaining memory is extended
memory. Four SIMM sockets are integrated on the system board. In the 433D, 466D, and
466M, one socket contains a 4-MB SIMM and three sockets are empty for installing up to
three additional SIMMs. The 4100M contains two 4-MB SIMMs and two sockets are
empty for installing additional SIMMs. The maximum possible memory is 128 MB.
The SIMM memory sockets accept 4-, 8-, 16-, or 32-MB SIMMs. When the standard
4-MB SIMM is removed (8-MB in the 4100M), four 32-MB SIMMs may be installed for a
total of 128 MB. High-speed RAM is 32 bits wide (no parity bits). SIMMs are 1 MB x 32
bit (4 MB), 4 MB x 32 bit (16 MB), and 8 MB x 32 bit (32 MB). There are no switches or
jumpers to set when SIMMs are added.
SIMMs install directly on the system board. Different size SIMMs may be intermixed. Each
SIMM is inserted into a socket or bank. The standard 4 MB of memory is installed in bank
0 in the PowerMate 433D, 466D, and 466M. The PowerMate 4100M has two 4 MB
SIMMs installed in banks 0 and 1. The system board's four SIMM sockets are assigned as
banks 0 through 3. See Section 3, Options, for installation instructions and SIMM memory
configurations.

Interrupt Controller

The interrupt controller operates as an interrupt manager for the entire AT system environ-
ment. The controller accepts requests from peripherals, issues interrupt requests to the
processor, resolves interrupt priorities, and provides vectors for the processor to determine
which interrupt routine to execute. The interrupt controller has priority assignment modes
that can be reconfigured at any time during system operations.
Table Section 1-3 I/O Address Map
I/O Device Name
Color/Graphics Adapter (CGA and EGA)
Diskette Controller
Asynchronous Adapter Port 1
CAUTION: SIMMs must match the tin metal
plating used on the system board SIMM sockets.
When adding SIMMs, use tin-plated SIMMs.
Technical Information 1-9