Acrosser AR-B1551 - Manual (Page 9)

AR-B1550 User’s Guide
7
Hex Range Device
050-05F Timer 2
060-06F 8042 keyboard/controller
070-071 Real-time clock (RTC), non-maskable interrupt (NMI)
080-09F DMA page registers
0A0-0A1 Interrupt controller 2
0C0-0DF DMA controller 2
0F0 Clear Math Co-processor
0F1 Reset Math Co-processor
0F8-0FF Math Co-processor
170-178 Reserved for Fixed disk 1
1F0-1F8 Fixed disk 0
201 Reserved for Game port
208-20A EMS register 0
218-21A EMS register 1
278-27F Parallel printer port (depends on setup assignment)
2E8-2EF Serial port (depends on setup assignment)
2F8-2FF Serial port (depends on setup assignment)
300-31F Prototype card/streaming type adapter
320-33F Reserved
378-37F
Parallel printer port (depends on setup assignment)
380-38F SDLC, bisynchronous
3A0-3AF Bisynchronous
3B0-3BF
Monochrome display and printer port 3 (LPT 3)
3C0-3CF EGA/VGA adapter
3D0-3DF Color/graphics monitor adapter
3E8-3EF Serial port 3 (depends on setup assignment)
3F0-3F7 Reserved for diskette controller
3F8-3FF Serial port (depends on setup assignment)
I/O Port Address Map
2.4.2 Real-Time Clock and Non-Volatile RAM
The AR-B1550 contains a real-time clock compartment that maintains the date and time in addition to storing
configuration information about the computer system. It contains 14 bytes of clock and control registers and
114 bytes of general purpose RAM. Because of the use of CMOS technology, it consumes very little power
and can be maintained for long periods of time using an internal Lithium battery. The contents of each byte in
the CMOS RAM are listed as follows: