EM83053DH Ver la hoja de datos (PDF) - ELAN Microelectronics

Número de pieza

componentes Descripción

Fabricante

EM83053DH

PC Microcontroller

ELAN Microelectronics 

Symbol

P61

P62

P63

P64

P65

P66

P67

CLK

DATA

V DD

OSCO

R_OSCI

EM83053DH

PC Micro-controller

I/O

Function

I

Row 1 Input scan line, internal pull high ( 17　Ω)

I

Row 2 Input scan line, internal pull high ( 17　Ω)

I

Row 3 Input scan line, internal pull high ( 17　Ω)

I

Row 4 Input scan line, internal pull high ( 17　Ω)

I

Row 5 Input scan line, internal pull high ( 17　Ω)

I

Row 6 Input scan line, internal pull high ( 17　Ω)

I

Row 7 Input scan line, internal pull high ( 17　Ω)

I/O

CLOCK line for IBM communication , internal pull high ( 2.2　Ω)

I/O

DATA line for IBM communication , internal pull high ( 2.2　Ω)

I

+5V Power Supply

O

CLOCK output

I

Connect 51K OHM resistor for 1.8432 MHz oscillation

6 Function Descriptions

6.1 Keyboard Buffer

The keyboard will buffer 16 bytes in a first-in-first-out order when the system is able to

receive scan codes from the keyboard. The response codes and repeated codes will

not be buffered. If keystrokes generate a multiple-byte sequence, the entire sequence

must fit into the buffer or the keystroke is discarded and a buffer-overrun condition

occurs.

6.2 Power-on Reset and Self Test

The duration of the keyboard Power-on-Reset(POR) should be within 150 milliseconds

and 2 seconds after the power is applied to the keyboard.

After executing POR , the keyboard executes a self test. The LEDs are turned on at the

beginning and off at the end of the self test. The self test takes a minimum 300

milliseconds and a maximum 500 milliseconds. If the self test is successful, a

completion code AA hex is sent to the system and the keyboard starts scanning. If the

self test fails, and error code is sent, the keyboard is disabled and waits for a command

from the system. The completion codes are sent between 450 milliseconds and 2.5

seconds after POR, and between 300 and 500 milliseconds after a RESET command is

acknowledged.

6.3 Keyboard Data Output

When the keyboard is ready to send data to the system, it first checks clock and data

lines. If either one is in the low state, data is stored in the keyboard buffer. If both are

in the high state, keyboard starts clocking data out. Data will be valid before the trailing

edge and after the leading edge of the clock pulse. During the transmission the

keyboard checks the clock line at least every 60 microseconds . If the system lowers

Product Specification (V1.0) 03.28.2003

•3

(This specification is subject to change without further notice)

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