Table 1: Digits vs. input data vs. tone output frequency (serial mode)

Digit

D4

D3

D2

D1

D0

Tone Output

Frequency (Hz)

100001

697

+1209

200010

697

+1336

300011

697

+1477

400100

770

+1209

500101

770

+1336

600110

770

+1477

700111

852

+1209

801000

852

+1336

901001

852

+1477

001010

941

+1336

*

01011

941

+1209

#

01100

941

+1477

A

01101

697

+1633

B

01110

770

+1633

C

01111

852

+1633

D

00000

941

+1633

¾

10000

697

¾

10001

770

¾

10010

852

¾

10011

941

¾

10100

1209

¾

10101

1336

¾

10110

1477

¾

10111

1633

DTMF OFF

11111

¾

Note: The codes not listed in Table 1 are not used D4 is MSB

HT9200A/HT9200B

Rev. 1.50

5

April 29, 2013

Functional Description

The HT9200A/B are DTMF generators for MCU inter-

faces. They are controlled by a MCU in the serial mode

or the parallel mode (for the HT9200B only).

Serial mode (HT9200A/B)

The HT9200A/B employ a data input, a 5-bit code, and a

synchronous clock to transmit a DTMF signal. Every

digit of a phone number to be transmitted is selected by

a series of inputs which consist of 5-bit data. Of the 5

bits, the D0(LSB) is the first received bit. The

HT9200A/B will latch data on the falling edge of the

clock (CLK pin). The relationship between the digital

codes and the tone output frequency is shown in Table

1. As for the control timing diagram, refer to Figure 1.

When the system is operating in the serial mode a

pull-high resistor is attached to D0~D3 (for parallel

mode) on the input terminal.