GENERAL DESCRIPTION
The Z89135/136 is a fully integrated, dual processor controller designed for low-cost digital telephone answering machines. The I/O control processor is a Z8® MCU with 24 KB of program memory, two 8-bit counter/timers, and up to 47 I/O pins. The DSP is a 16-bit processor with a 24-bit ALU and accumulator, 512 x 16 bits of RAM, single cycle instructions, and 6K word program ROM plus constants memory. The chip also contains a half-flash 8-bit A/D converter with up to 128 kHz sample rate and 10-bit PWM D/A converter. The sampling rates for the converters are programmable. The precision of the 8-bit A/D may be extended by resampling the data at a lower rate in software.
   
FEATURES
■ 24 KB of Z8 Program ROM (Z89135)
■ Watch-Dog Timer and Power-On Reset
■ Low Power STOP Mode
■ On-Chip Oscillator which Accepts a Crystal or External
    Clock Drive
■ Two 8-Bit Z8 Counter Timers with 6-Bit Prescaler
■ Global Power-Down Mode
■ Low Power Consumption - 200 mW (typical)
■ Two Comparators with Programmable Interrupt Priority
■ Six Vectored, Priority Z8 Interrupts
■ RAM and ROM Protect
■ Clock Speed of 20.48 MHz
■ 16-Bit Digital Signal Processor (DSP)
■ 6K Word DSP Program ROM
■ 512 Words On-Chip DSP RAM
■ 8-Bit A/D Converter with up to 128 kHz Sample Rate
■ 10-Bit PWM D/A Converter (4 kHz to 64 kHz)
■ Three Vectored, Prioritized DSP Interrupts
■ Two DSP Timers to Support Different A/D and
■ D/A Sampling Rates
■ Z8 and DSP Operation in Parallel
■ IBM® PC-Based Development Tools
■ Developer’s Toolbox for T.A.M. Applications