HT95R35 datasheet(49/73 Pages) HOLTEK

49 / 73 page

HT95R35

Rev. 1.00

October 7, 2009

DTMF Generator

The device includes a fully integrated DTMF, Dual-Tone Multiple-Frequency, generator function. This functional block

can generate the necessary16 dual tones and 8 single tones for DTMF signal generation. The signal will be provided on

the DTMF pin of the device. The DTMF generator also includes a power down and a tone on/off function. The clock

source for the DTMF generator is the 3.58MHz oscillator. Before the DTMF function is used, the device must have been

placed into the Normal mode.

DTMF Generator Control

The DTMF Generator is controlled by two registers, a control register known as DTMFC and a data register known as

DTMFD. The power down mode will terminate all the DTMF generator functions and can be activated by setting the

D_PWDN bit in the DTMFC register to 1. These two registers, DTMFC and DTMFD are still accessible even if the

DTMF function is in the power down mode. The generation duration time of the DTMF output signal should be deter-

mined by the software. The DTMFD register value can be changed as desired, at which point the DTMF pin will output

the new dual-tone simultaneously.

DTMF Generator Frequency Selection

The DTMF pin output is controlled using a combination of the D_PWDN, TONE, TR~TC bits.

Control Register Bits

DTMF Pin Output Status

D_PWDN

TONE

TR4~TR1/TC4~TC1

1/2 VDD

Any valid value

16 dual tones or 8 signal tones, bias at 1/2 VDD

D T M F C R e g i s t e r

b 7

b 0

T O N E

D T M F G e n e r a t o r P o w e r D o w n E n a b l e

1 : e n a b l e

0 : d i s a b l e

D _ P W D N

N o t i m p l e m e n t e d , r e a d a s " 0 "

T o n e O u t p u t E n a b l e

1 : e n a b l e

0 : d i s a b l e

N o t i m p l e m e n t e d , r e a d a s " 0 "

DTMF Generator Control Register

R O W 1

R O W 2

R O W 3

R O W 4

C O L 1 C O L 2 C O L 3 C O L 4

DTMF Dialing Matrix

D T M F D

b 7

b 0

H i g h g r o u p ( c o l u m n ) t o n e f r e q u e n c y s e l e c t

L o w g r o u p ( r o w ) t o n e f r e q u e n c y s e l e c t

T R 4

T R 3

T R 2

T R 1

T C 4

T C 3

T C 2

T C 1

DTMF Generator Data Register

HT95R35 Datasheet(PDF) 49 Page - Holtek Semiconductor Inc

HT95R35 Datasheet(HTML) 49 Page - Holtek Semiconductor Inc

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