Architectural Overview

The Z86L972/Z86L973/Z86L974 family is designed to be used in a wide variety of embedded control applications including home appliances, infrared (IR) remote controls, security systems, and wireless keyboards.

Features

• Two independent analog comparators

• Controlled current output

• 489 bytes of RAM

– 233 bytes of general-purpose register-based RAM

– 256 bytes of RAM mapped into the program memory space that can be

used as data RAM or executable RAM

• 4K/8K/16K bytes of ROM

Counter/Timers

• Special architecture to automate generation and reception of complex pulses

or signals:

– Programmable 8-bit counter/timer (T8) with two 8-bit capture registers and

two 8-bit load registers

– Programmable 16-bit counter/timer (T16) with one 16-bit capture register

pair and one 16-bit load register pair

– Programmable input glitch filter for pulse reception

• One general-purpose 8-bit counter/timer (T1) with 6-bit prescaler

Input/Output and Interrupts

• Thirty-two I/Os, twenty-nine of which are bidirectional I/Os with programmable

resistive pull-up transistors (24 I/Os are available in the 28-pin configuration)

• Sixteen I/Os are selectable as stop-mode recovery sources

• Six interrupt vectors with nine interrupt sources

– Three external sources

– Two comparator interrupts

– Three timer interrupts

– One low-battery detector flag

Operating Characteristics

• 8-MHz operation

• 2.3 V to 5.5 V operating voltage

• Low power consumption with three standby modes:

– Stop

– Halt

– Low Voltage Standby

• Low-battery detection flag

• Low-voltage protection circuit (also known as VBO, or voltage brownout,

circuit)

• Watch-dog timer and power-on reset circuits

User-Programmable Option Bits

• Clock source—RC/other (LC, resonator, or crystal)

• Watch-dog timer permanently enable

• 32-kHz crystal

• Port 20–27 pull-up resistive transistor

• Port 40–42 pull-up resistive transistor

• Port 44–47 pull-up resistive transistor

• Port 50–51 pull-up resistive transistor

• Port 54–57 pull-up resistive transistor

• Port 60–63 pull-up resistive transistor

• Port 64–67 pull-up resistive transistor