ST6380 datasheet(34/82 Pages) STMICROELECTRONICS

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ST6380, ST6381, ST6382, ST6383, ST6388, ST6389

TIMERS (Cont’d)

4.2.2 Timer Status Control Registers (TSCR)

Timers 1 and 2

Address: D4h (Timer 1), DCh (Timer 2) - Read/

Write

Reset Value: 00h

TMZ. Low-to-high transition indicates that the tim-

er count register has decremented to zero. This bit

must be cleared by user software before to start

with a new count.

ETI. This bit, when set, enables the timer interrupt

(vector #3 for Timer 1, vector #2 for Timer 2 re-

quest). If ETI=0 the timer interrupt is disabled. If

ETI= 1 and TMZ= 1 an interrupt request is gener-

ated.

D5. This is the timers enable bit D5. It must be

cleared to 0 together with a set to 1 of bit D4 to en-

able Timer 1 and Timer 2 functions. It is not imple-

mented on registers TSCR2.

D4. This is the timers enable bit D4. This bit must

be set to 1 together with a clear to 0 of bit D5 to en-

able all Timers (Timer 1 and 2) functions. It is not

implemented on registers TSCR2.

PSI. Used to initialize the prescaler and inhibit its

counting while PSI = 0 the prescaler is set to 7Fh

and the counter is inhibited. When PSI = 1 the

prescaler is enabled to count downwards. As long

as PSI= 0 both counter and prescaler are not run-

ning.

PS2-PS0. These bits select the division ratio of the

prescaler register. (see Table 12)

The TSCR1 and TSCR2 registers are cleared on

reset. The correct D4-D5 combination must be

written in TSCR1 by user's software to enable the

operation of Timer 1 and 2.

Table 12. Prescaler Division Factors

4.2.3 Timer Counter Registers (TCR)

Timer Counter 1 and 2

Address: D3h (Timer Counter 1), DBh (Timer

Counter 2) - Read/Write

Reset Value: FFh

Bit 7-0 = D7-D0:

Counter Bits.

4.2.4 Timer Prescaler Registers (PSCR)

Timer Prescalers 1 and 2

Address: D2h (Timer Prescaler 1), DAh (Timer

Prescaler 2) - Read/Write

Reset Value: 7Fh

Bit 7 = D7: Always read as "0".

Bit 6-0 = D6-D0: Prescaler Bits.

TMZ

ETI

PSI

PS2

PS1

PS0

Timers

Disabled

Enabled

Reserved

PS2

PS1

PS0

Divided By

000

001

010

011

100

101

110

111

128

ST6380 数据表(PDF) 34 Page - STMicroelectronics

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