HL14104 Просмотр технического описания (PDF) - Hyundai Micro Electronics

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Компоненты Описание

производитель

HL14104

LCD Driver

Hyundai Micro Electronics 

8. Key Scan Function

HL15604

1) Key Scan Timing

The key scan period is 384T. The HL14104 scans the key twice and determines

that a key has been pressed when the key data agrees. It outputs a key data read

request 800T after starting a key scan. If the key data does not agree and a key

was pressed at that point, it scans the key again.Thus the HL14104 cannot detect

a key press shorter than 800T.

KS1 *) 1

1

*)

KS2 *)

2

2

*)

KS3 *)

3

3

*)

KS4 *)

4

4

*)

KS5 *)

5

5

*)

KS6 *)

6

768T

6 *)

Key on

*) In sleep mode the high / low state of these pins is determined by the S0,S1 bits in the control data.

Key scan output signals are not output from pins that are set low.

2) In normal mode

• The pins KS1 to KS6 are set high.

• When a key is pressed a key scan is started and the keys are scanned until all

keys are released. Multiple key presses are recognized by determining whether

multiple key data bits are set.

• If a key is pressed for longer than 800T ( where T=1/fosc ) the HL14104

outputs a key data read request (a low level on SO pin) to the controller. The

controller acknowledges this request and reads the key data. However, if CE

is high during a serial data transfer, SO will be set high.

• After the controller reads the key data, the key data read requests is cleared (

SO pin is set high ) and the HL14104 performs another key scan. Also note

that SO pin, being an open-drain output, requires a pull-up resistor.

13

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