System Board Devices And Features - IBM Personal System/2 60 Technical Reference

Device Type Features
Microprocessor -- 80286
24-bit address and 16-bit
data interface
System Timers
1
Channel 0 — System timer
Channel 2 — Tone generation
for speaker
Channel 3 — Watchdog timer
ROM Subsystem
--
128KB (KB = 1024 bytes)
RAM Subsystem
--
1MB (MB = 1,048,576 bytes)
Expandable on the channel
CMOS
RAM
-—
64-byte CMOS RAM with
Subsystem
real-time clock/calendar
2KB CMOS RAM extension
Battery backup
Video Subsystem
1
Auxiliary connector on the channel
Analog output
256KB video memory
Audio Subsystem 1 Driven by:
- System-timer channel 2
- The 'audio sum node' signal.
DMA Controller
1
Eight independent DMA channels
Single or burst transfers and
read verification
Interrupt Controller
1
16 levels of system interrupts
Interrupts are level-sensitive
Keyboard/Auxillary
1
Keyboard connector
Device Controller
Auxiliary device connector
Password security
Diskette Drive 1 Supports:
Controller
- 720KB formatted diskette density
- 1.44MB formatted diskette density.
Serial Controller
1,2
RS-232C interface
Parallel Controlier
Micro Channel
Math Coprocessor
Socket
Programmable as serial port 1 or 2
FIFO mode* and character mode
Programmable as parallel port 1, 2, or 3
Supports bidirectional input and output
Eight channel connectors for
Type 3 adapters
- 8- or 16-bit device support
- One with an auxiliary video
extension
- One occupied by the fixed disk
drive adapter
Supports 80287 math coprocessors
Same clock speed as the system
microprocessor
Figure
1-1. System Board Devices and Features