HT6230 View Datasheet(PDF) - Holtek Semiconductor

Part Name

Description

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HT6230

Infrared Remote Encoder

Holtek Semiconductor 

logic 1. If the sense input comes from XIN, the

corresponding command code together with

the system code stored in the system latches

are generated.

· Two-key system mode

The device goes into this mode by switching

the MS input pin to high state. The pull-high

resistors are only connected to XIN inputs ex-

cept the first scan cycle. In the first scan cycle,

there only exists pull-high resistors in ZIN in-

puts. In this mode, the legal key operation is

that exactly one XIN and one ZIN are con-

nected to two DRS drivers. In the first scan

duration, it detects which key in Z-key matrix

is pressed and generates an enable signal to

latch the system latches. While in the second

scan duration, it detects which key in the

X-key matrix is pressed and generates an en-

abled signal to latch the command latches. Af-

ter being latched, the system and command

codes are transmitted.

Control bit

A control bit is added after two start bits and

will be complemented if one key is released. The

decoder can decide whether the next code is a

new command or not.

Oscillator

The embedded part of the oscillator is an

RC-oscillation circuit. The OSC pin is the input

terminal of the RC-oscillation circuit and is con-

nected to an external ceramic resonator (429kHz).

A resistor of 6.8kW must be in series with the

resonator. The resonator and resistor are

grounded at one side.

Reset (after key release)

In a complete code repetition time, as shown in

the figure below, the following situation of key

release results in a reset action.

C ode 1

T code

T sep

R e p e titio n tim e

D ebounce

tim e

C ode 2

T code

HT6230

· During Tsep and debounce time, the device

will reset immediately if a key is released.

· During Scan cycle in Tcode, a reset will occur

if a key is released in three cases described be-

low:

¨ When one of the key scan drivers is in the

low state

¨ Before that key has been detected

¨ When MS is high and there is no wired con-

nection in Z-key matrix

Test pins (TT1 and TT2)

There are four modes by the combination of TT1

and TT2.

TT1 TT2

Mode

0

0 Normal mode

1

1 Reset

1

0 Test mode 1

0

1 Test mode 2

6

April 19, 2000

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