Toshiba TW40F80 manual Local Key Detection Method, 6 Local key assignment -1 Local key assignment

Models: TW40F80

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8. LOCAL KEY DETECTION METHOD

8. LOCAL KEY DETECTION METHOD

17

18

Local key detection in the N5SS chassis is carried out by

using analog like method which detects a voltage appears at

local key input terminals (pins 17 and 18) of the microcom-

puter when a key is pushed. With this method using two

SA08

SA01

local key input terminals (pins 17 and 18), key detection up to maximum 14 keys will be carried out.

SA06

SA05

SA07

SA02

The circuit diagram shown left is the local key circuit. As

 

 

can be seen from the diagram, when one of keys among SA-

 

01 to SA-08 is pressed, each of two input terminals (pins 17

SA03

and 18) developes a voltage VIN corresponding to the key

 

pressed. (The voltage measurement and key identification

 

are carried out by an A/D converter inside the microproces-

SA04

sor and the software.

Fig. 3-6 Local key assignment

Table 3-1 Local key assignment

Key No.

Function

Key No.

Function

 

 

 

 

SA-02

POWER

SA-01

DEMO START/STOP

 

 

 

 

SA-03

CH UP

 

 

 

 

 

 

SA-04

CH DN

 

 

 

 

 

 

SA-05

VOL UP

 

 

 

 

 

 

SA-06

VOL DN

 

 

 

 

 

 

SA-07

ANT/VIDEO, ADV

 

 

 

 

 

 

SA-08

MENU

 

 

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Toshiba TW40F80 Local Key Detection Method, 6 Local key assignment -1 Local key assignment, Function, Demo Start/Stop