CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS

5.4BASIC INTERVAL TIMER

The μPD75402A is equipped with an 8-bit basic interval timer which has the following functions:

(a)Standard time generation (2 different time intervals)

(b)Reading counter contents

This basic interval timer can also be used as a watchdog timer for the detection of inadvertent program looping.

5.4.1Basic Interval Timer Configuration

The configuration of the basic interval timer is shown in Fig. 5-21.

Fig. 5-21 Basic Interval Timer Configuration

 

 

 

 

Clear

 

Clear

 

From Clock

 

 

 

 

 

 

 

 

 

 

 

 

 

Generation

 

 

 

 

 

 

 

Circuit

 

 

 

 

 

 

 

fxx/2 5

MPX

 

 

Basic Interval Timer

Set

 

 

 

 

 

( 8-Bit Frequency Divider)

 

 

Vectored

 

 

 

 

 

 

 

 

 

 

 

 

 

fxx/2 9

 

 

 

 

Bt

IRQBT

Interrupt

 

 

 

 

BT

Interrupt

 

Request

 

 

 

 

Request

 

Signal

 

 

 

 

 

Flag

 

 

BTM3

BTM2

1

1

BTM

 

 

 

SET1*

 

4

 

8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Internal Bus

 

 

 

*Instruction execution

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NEC PD75402A Peripheral Hardware Functions Basic Interval Timer, Basic Interval Timer Configuration, Mpx, BTM3 BTM2