NEC MT-2550-24874C, Руководство по обслуживанию

Страница: 27 / 214

Technical Information 1-11
SIMMs install directly in the four sockets on the system board. The four sockets are
assigned as Bank 0 (2 sockets) and Bank 1 (2 sockets). All configurations have two SIMMs
installed in Bank 1.
SIMMs must be installed in pairs of the same memory type and size. Both sockets must be
populated within a bank for the system to work. No switch or jumper settings are required
when the memory is changed. The system BIOS automatically detects the SIMMs. See
“Checking the Memory in the System” in Section 3 for the valid configurations.
Interrupt Controller
The interrupt controller operates as an interrupt manager for the entire system environment.
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.
The interrupt levels are described in Table 1-5. Interrupt-level assignments 0 through 15 are
listed in order of decreasing priority. See Section 2, “Setup and Operation,” for information
on changing the interrupts using Setup.
Table 1-5 Interrupt Level Assignments
Interrupt Priority Interrupt Device
NMI I/O channel check
IRQ00 Reserved, Interval Timer
IRQ01 Reserved, Keyboard buffer full
IRQ02 Reserved, Cascade interrupt from slave
IRQ03 Serial Port 2 (COM2)
IRQ04 Serial Port 1 (COM1)
IRQ05 Audio/LPT2 plug and play option/user-available
IRQ06 Diskette Drive Controller
IRQ07 Parallel Port 1 (LPT1)
IRQ08 Real-time clock
IRQ09 User-available