HE84760 Datasheet, PDF (25/31 Pages) King blillion Electronics Co.,Ltd. – 8-bit Micro-controller

King Billion Electronics Co., Ltd
駿億電子股份有限公司
HE84760
HE80000 SERIES
PWM Output Driver Selection
PWMC[6..4]
000
001
010
011
100
101
110
111
Number of Driver
off
1
2
3
2
3
4
5
17. Dual-Tone Multiple Frequency Generator
The Dual-Tone Multiple Frequency (DTMF) generator is used to generate the Tone Dialing signal used in
Telecommunication applications. In fact, it can be used to generate any two channel sinusoidal wave
signal with frequencies ranging from 1 ~ 4095 Hz with 1 Hz resolution. The DTMF generator derives its
clock from 32768 Hz.
The DTMF generator is controlled through DTMFC (DTMF Control) Register. DTMFC can only be
written, and it can not be read. The DTMFC register actually maps to Row Register, Column Register and
Command Register. So when writing to DTMFC, the actual register being written is determined by Bit 7
and 6.
DTMFC
ROW HIGH
ROW LOW
COL HIGH
COL LOW
COMMAND
BIT7
0
0
0
0
1
BIT6
0
0
1
1
1
BIT5
M11
M5
M11
M5
HOOK
BIT4
M10
M4
M10
M4
KT
BIT3
M9
M3
M9
M3
CH1
BIT2
M8
M2
M8
M2
CH0
BIT1
M7
M1
M7
M1
DTMF
BIT0
M6
M0
M6
M0
HB(1)/LB(0)
Bit 5 of command register (HOOK bit) is the main switch of DTMF Generator block. When HOOK Bit
is ‘1’, the entire block will be turned off and all internal registers will be not reset. When HOOK Bit is
‘0’, the block will be turned on.
The Row and Column registers determine the frequencies of two channels sine wave generator. As they
are 12-bit register, they need to be divided into high parts and low part when writing. The procedure of
changing the Row and Column frequency is by selecting High or Low byte to be written in the command
register, write to the target register, then toggle the HB/LB bit, and then write to the second part of the
register. When both frequencies are set, the DTMF tone can be sent to DTMFO output by turning on bit 1
(DTMF bit) of command register. When DTMF bit is ‘1’, DTMF signal can be output, and the output is
disabled when DTMF bit is ‘0’.
August 15, 2003
Page 25 of 31
V1.2
This specification is subject to change without notice. Please contact sales person for the latest version before use.