Specifications

Counter/Timers

A new count can be written into the counter/timers at any time

without reprogramming the TMD register. Care must be taken to

be consistent with the Read/Write Mode each time the new count

is programmed. As an example, assume that counter/timer 0 is

programmed with a Read/Write Mode of two bytes. Two bytes

must be written to counter/timer 0 each time a new count is

specified. The same applies for reading counter/timer 0; that is,

two count bytes must be read at a time.

Address: Base + 3

76543210

Binary or BCD

0 Binary

1 BCD

CMODE

Count Mode

000 Mode 0

001 Mode 1

x10 Mode 2

x11 Mode 3

100 Mode 4

101 Mode 5

RWM

Read/Write Mode

00 Count Latch command

01 Lower byte only

10 Higher byte only

11 Lower byte followed by

higher byte

Select Counter

00 TCT0

01 TCT1

10 TCT2

11 Multiple Latch command

Note: x = Don’t Care

Figure 7–2. Counter/Timer General Mode Register.

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