Holtek HT95R35 DTMF电话控制方案

Holtek公司的HT95R35 是带DTMF接收器的8位电话通信用MCU, 具有ROM为16K×16、RAM为2112B、I/O为44引脚、Stack数目为8-level、内建三个16位计时器、一个RTC 计时器及四个外部中断触发等功能，除此之外，HT95R35在功能上更提供一个12-bit D/A及SPI/I2C通讯接口，在封装方面则提供64 LQFP的封装型式。利用内建12-bit D/A，搭配SPI/I2C做为与外部Flash Voice ROM通讯接口，可产生多种语音，非常适合带语音功能通讯产品的应用如多功能电话、无线电话、录音机、家庭安防等。本文介绍了HT95R35主要特性和方框图以及SPI,I2C方框图和单端输入与差分输入的应用电路.

The HT95R35 MCU is an 8-bit high performance, RISC architecture microcontroller device specially designed for telephone applications. Device flexibility is enhanced with their internal special features such as power-down and wake-up functions, DTMF generator, DTMF receiver, PFD driver, SPI and I2C interface, audio DAC output, etc. These features combine to ensure applications require a minimum of external components and therefore reduce overall product costs.

Having the advantages of low-power consumption, high-performance, I/O flexibility as well as low-cost, these devices have the versatility to suit a wide range of application possibilities such as deluxe feature phone, cordless phones, fax and answering machines, etc. The device is best suited for phone products that comply with versatile dialer specification requirements for different areas or countries. The device is fully supported
by the Holtek range of fully functional development and programming tools, providing a means for fast and efficient product development cycles.

HT95R35主要特性:

_ Operating voltage:

  fSYS= 3.58MHz: 2.2V~5.5V

  fSYS= 14.32MHz: 4.5V~5.5V

_ 16K_16 OTP type Program Memory

_ 2112_8 Data Memory

_ 42 bidirectional I/Os with pull-high options

_ 2 NMOS output-only lines

_ External interrupt input

_ Three 16-bit timers with interrupts

_ Timer external input

_ 8-level stack

_ 32768Hz system oscillator

_ 32768Hz to 14.32MHz frequency-up PLL circuit

_ Real time clock function

_ Watchdog timer function

_ PFD driver output

_ Dual Serial Interfaces: SPI and I2C

_ DTMF generator

_ DTMF receiver

_ 12-bit Audio DAC output

_ Power-down and wake-up feature for power-saving operation: Idle mode, Sleep mode, Green mode and normal mode

_ Up to 0.28_s instruction cycle with 14.32MHz system clock at VDD=4.5V~5.5V

_ Bit manipulation instructions

_ Table read function

_ 63 powerful instructions

_ All instructions executed in 1 or 2 machine cycles

_ Low voltage reset function

_ Supported by comprehensive suite of hardware and software tools

_ 64-pin LQFP package


图1.HT95R35方框图

图2.HT95R35 SPI方框图

图3.HT95R35 I2C方框图

图4.HT95R35单端输入应用电路

图5.HT95R35差分输入应用电路