Specifications

Table 5-2. Little Board/PC I/O Map
I/O ADDRESS FUNCTION
FFFO - FFFFh
V40 internal
control
registers
0400 - FFEFh Not available.
03F8 - 03FFh
PC Serial Port Hpri .. ryu option
03FO - 03F7h Floppv disk controller ports (37065B)
3F2 - FOC Digital output register (LDOR)
3F4 - FOC Main status register
3F5 - FOC Data register
3F7 - FOC Control register (LOCR)
03BC - 03BFh Parallel
pr inter IIsecondarY" opt i on
0378 - 037Fh Parallel
printer IIprimaryll option
0338h Jumper input port. SCSI 10, floppv type,
and V40 serial port handshake input.
0330 - 0337h SCSI controller ports (53C8O)
(See 53C8O table later in this chapter.)
02F8 - 02FFh PC Serial Port HsecondarY" option
OOFO - OOF3h V40 Serial Port
OOAO • OOAFh
NMI Enable register
0080 • 0083h
DMA page registers ("eI1I.IlatedH)
80 • reserved
81 • PC DNA Channel 2
82 • PC DNA Channel 3
83 • PC DNA Channel 1
0060 • 0063h
Speaker control ports
61 • Bit 0 = CTC2 output gate
61 • Bit 1 = Speaker enable signal
0040 - 004Fh
Counter/Timer Controller ports
42 - Frequency count/status register
43 - Timer mode register
0020 - 002Fh Interrupt controller ports
0010 - 001Fh
V40 DNA controller registers (llactual
ll
)
0000 - OOOFh "8237A DMA controller
H
registers (leI1I.Ilated")
NOTE
The following I/O port addresses cannot be applied to the
PC expans i on bus:
OO-OFh
6O-6Fh AO-AFh
20-2Fh
72h,73h CO-CFh
40-4Fh
8O-8Fh
EO-EFh
5-3