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
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