ZLR64400ROMMCU datasheet(78/155 Pages) ZILOG

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PS024502-1205

P R E L I M I N A R Y

Counter/Timer Functional Blocks

ZLR64400 ROM MCU

Product Specification

Initiating PING-PONG Mode

First, ensure that both counter/timers are not running. Set T8 into SINGLE-PASS mode

(CTR0, bit 6), set T16 into SINGLE-PASS mode (CTR2, bit 6), and set the Ping-Pong

mode (CTR1 bits [3:2]). These instructions are not consecutive and can occur in random

order. Finally, start PING-PONG mode by enabling either T8 (CTR0, D7) or T16 (CTR2,

D7). The initial value of T8 or T16 must not be ï. If you stop the timer and restart the

timer, reload the initial value to avoid an unknown previous value.

During PING-PONG Mode

The enable bits of T8 and T16 (CTR0, D7; CTR2, D7) are set and cleared alternately by

hardware. The time-out bits (CTR0, bit 5; CTR2, bit 5) are set every time the counter/tim-

ers reach the terminal count.

Timer Output

The output logic for the timers is illustrated in Figure 30. P34 is used to output T8_OUT

when bit 0 of CTR0 is set. P35 is used to output the value of T16_OUT when bit 0 of

CTR2 is set. When bit 6 of CTR1 is set, P36 outputs the logic combination of T8_OUT

and T16_OUT via bits [4:5] of CTR1.

Figure 29. Ping-Pong Mode Diagram

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ZLR64400ROMMCU Datasheet(PDF) 78 Page - Zilog, Inc.