FANUC Robotics America V7865* - Manual (Page 44)

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V7865 Product Manual
I/O Port Map
Like a desktop system, the V7865 includes special input/output instructions that
access I/O peripherals residing in I/O addressing space (separate and distinct from
memory addressing space). Locations in I/O address space are referred to as ports.
When the CPU decodes and executes an I/O instruction, it produces a 16-bit I/O
address on lines A00 to A15 and identifies the I/O cycle with the M/I/O control line.
Thus, the CPU includes an independent 64KB I/O address space, which is accessible
as bytes, words or longwords.
Standard hardware circuitry reserves only 1,024 byte of I/O addressing space from
I/O $000 to $3FF for peripherals. All standard PC I/O peripherals, such as serial and
parallel ports, hard and floppy drive controllers, video system, real-time clock, system
timers and interrupt controllers are addressed in this region of I/O space. The BIOS
initializes and configures all these registers properly; adjusting these I/O ports
directly is not normally necessary.
The assigned and user-available I/O addresses are summarized in the I/O Address
Map, Table 2-2.
Table 2-2 V7865 I/O Address Map
I/O Address
Range
Size In
Bytes
HW Device PC/AT Function
$000 - $00F 16 DMA Controller 1
$010 - $01F 16 Reserved
$020 - $021 2 Master Interrupt Controller
$022 - $03F 30 Reserved
$040 - $043 4 Programmable Timer
$044 - $05F 30 Reserved
$060 - $064 5 Keyboard, Speaker, System Configuration
$065 - $06F 11 Reserved
$070 - $071 2 Real-Time Clock
$072 - $07F 14 Reserved
$080 - $08F 16 DMA Page Registers
$090 - $091 2 Reserved
$092 1 Alt. Gate A20/Fast Reset Register
$093 - $09F 11 Reserved
$0A0 - $0A1 2 Slave Interrupt Controller
$0A2 - $0BF 30 Reserved
$0C0 - $0DF 32 DMA Controller 2