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
