參數(shù)資料
型號(hào): HD4074654
廠商: Hitachi,Ltd.
英文描述: 4-Bit Single-Chip Microcomputer
中文描述: 4位單片機(jī)
文件頁數(shù): 78/109頁
文件大?。?/td> 430K
代理商: HD4074654
HD404654 Series
78
DTMF Generator Circuit
The MCU provides a dual-tone multifrequency (DTMF) generator circuit. The DTMF signal consists of
two sine waves to access the switching system.
Figure 63 shows the DTMF keypad and frequencies. Each key enables tones to be generated corresponding
to each frequency. Figure 64 shows a block diagram of the DTMF circuit.
The OSC clock (400 kHz, 800 kHz, 2 MHz, 3.58 MHz or 4 MHz) is changed into four clock signals
through the division circuit (1/2, 1/5, 1/9 and 1/10). The DTMF circuit uses one of the four clock signals,
which is selected by system clock select register 1 (SSR1: $029) and system clock select register 2 (SSR2:
$02A) depending on the OSC clock frequency. The DTMF circuit has transformed programmable dividers,
sine wave counters, and control registers.
The DTMF generation circuit is controlled by the following three registers.
1
2
3
A
4
5
6
B
7
8
9
C
*
0
#
D
R1 (697 Hz)
R2 (770 Hz)
R3 (852 Hz)
R4 (941 Hz)
C
C
C
C
Figure 63 DTMF Keypad and Frequencies
相關(guān)PDF資料
PDF描述
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
HD4074654H 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:4-Bit Single-Chip Microcomputer
HD4074654S 制造商:HITACHI 制造商全稱:Hitachi Semiconductor 功能描述:4-Bit Single-Chip Microcomputer
HD4074678H 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Microcontroller
HD4074709C 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Microcontroller
HD4074709FS 制造商:未知廠家 制造商全稱:未知廠家 功能描述:4-Bit Microcontroller