HE84760 Datasheet, PDF (26/31 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
In addition to dual tone generation, the DTMF generation can be used to generate single channel tone
determined by either ROW frequency or COL frequency or switching between the two frequencies with
continuous phase. This feature is useful for generating phase coherent FSK (Frequency Shift Keying) tone
as often used in Telecommunication.
The frequency range is further expanded to 4095 Hz to cover the more range. For example, the Caller
Alerting Tone requires 2130 and 2750 Hz tones to be generated which is beyond the range of the original
design.
Bit3 Bit2
Channel Select
0 0 Row + Column
0 1 Row frequency
1 0 Column frequency.
11
x
In addition to DTMF generation function, this function block also provides others features which are
useful for the phone application. For example, Bit 4 (KT bit) of command register controls the generation
of 1024 Hz square wave to provide the audio feedback to the user in response to key presses. When KT
bit is ‘1’, square wave generation is enabled, and when KT bit ‘0’, the square wave is disabled. The
DTMF and Keytone outputs are not dedicated output pins, but are multiplexed with I/O PRT10[0] and
PRT10[1]. The functions of these two pins are determined by mask options MO_TONE and
MO_KEYTONE.
Mask Option
MO_TONE
MO_KEYTONE
Value
Function
0 Normal I/O pin (PRT10[0])
1 TONEO output through prt10[0]
0 Normal I/O pin (PRT10[1])
1 KEYTONE output through prt10[1]
August 15, 2003
Page 26 of 31
V1.2
This specification is subject to change without notice. Please contact sales person for the latest version before use.