Octagon PC-510, Руководство пользователя

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11-7
PC-510 user’s manual EZ I/O
To read ports A and C, issue the following commands:
PORTA = INP(330h) (port A)
PORTC = INP(333h) (port B)
≡
Enhanced INT 17h function definitions
This section provides definitions for the following functions: Initialize
EZ I/O 1, Write EZ I/O 1, Read EZ I/O 1, Initialize EZ I/O 2, Write EZ I/O 2,
and Read EZ I/O 2.
Initialize EZ I/O 1
Function: efh
Subfunction: 00h
Purpose: To set the directions and to program the initial
values of an EZ I/O port.
Calling registers:
Ah efh
AL 00h
DI Port A configuration
xxxxxxxx xxxxxxxxB
xxxxxxx Initial data for port A
xxxxxxxxB direction; 1->output, 0->input
BX Port B configuration
xxxxxxxx xxxxxxxxB
xxxxxxxx Initial data for port B
xxxxxxxxB direction; 1->output, 0->input
CX Port C configuration
xxxxxxxx xxxxxxxxB
xxxxxxxx Initial data for port C
xxxxxxxxB direction; 1->output, 0->input
DX ffffh
Return registers: Carry flag cleared if successful
Carry flag set if error
AL Error code
Comments: This function is used to initialize the first EZ I/O (i.e., the
EZ I/O that has the higher I/O address when two EZ I/O
chips are present on a board) before normal use.
Programming example:
/* Inline assembly code for Borland C++ 3.1 */
asm {
mov ax,0ef00h
mov di,00ffh /*port A all outputs, init data=all 0’s */
mov bx,55ffh /*port B all outputs, init data=55h*/
mov cx,0000h /*port C all inputs*
mov dx,0ffffh
int 17h
}