P89C738ABB Просмотр технического описания (PDF) - Philips Electronics

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производитель

P89C738ABB

8-bit Flash microcontrollers

Philips Electronics 

Philips Semiconductors

8-bit Flash microcontrollers

Product specification

P89C738; P89C739

Table 11 Timer 0; Timer 1 mode select

M1

M0

OPERATING

0

0

Timer TL0; TL1 serves as 5-bit prescaler.

0

1

16-bit Timer/Counter TH0; TH1 and TL0; TL1 are cascaded; there is no prescaler.

1

0

8-bit auto-reload Timer/Counter TH0; TH1 holds a value which is to be reloaded into

TL0; TL1 each time it overflows.

1

1

Timer 0: TL0 is an 8-bit Timer/Counter controlled by the standard Timer 0 control bits.

TH0 is an 8-bit timer only controlled by Timer 1 control bits.

1

1

Timer 1: Timer/Counter 1 stopped.

10.1.2 Timer/Counter Control Register (TCON)

Table 12 Timer/Counter Control Register (SFR address 88H)

7

6

5

4

3

2

1

0

TF1

TR1

TF0

TR0

IE1

IT1

IE0

IT0

Table 13 Description of TCON bits

BIT

7 and 5

6 and 4

3 and 1

2 and 0

SYMBOL

DESCRIPTION

TF1 and TF0 Timer 1 and Timer 0 overflow flags. Set by hardware on Timer/Counter overflow.

Cleared by hardware when processor vectors to interrupt routine.

TR1 and TR0 Timer 1 and Timer 0 run control bits. Set/cleared by software to turn Timer/Counter

on/off.

IE1 and IE0 Interrupt 1 and Interrupt 0 edge flags. Set by hardware when external interrupt edge

detected. Cleared when interrupt processed.

IT1 and IT0 Interrupt 1 and Interrupt 0 type control bits. Set/cleared by software to specify falling

edge/LOW level triggered external interrupts.

1998 Apr 07

20

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