ST52T441 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST52T441

8-BIT INTELLIGENT CONTROLLER UNIT (ICU) Timer/PWM, Analog Comparator, Triac/PWM Timer, WDG

STMicroelectronics 

Figure 9.2 Timer 0 External START/STOP Mode

ST52T400/T440/E440/T441

Level

Edge

s ta rt

s ta rt

sto p

sto p

sta rt

s ta rt

R eset

C lo c k

C o u n te d

0

1

2

3

4

4

0

1

V a lu e

EDGE: After the reset, on the first TSTRT rising

edge, the TIMER starts counting and, at the next

rising edge, it stops. In this manner, the period of

an external signal may be measured.

The Timer output signal, TIMEROUT, is a signal

with a frequency equal to the 16 bit-Prescaler out-

put signal, TMRCLK, divided by the Output Regis-

ter PWM_COUNT value (8 bit) (Output Registers

9, Table 2.3), that is the value to count.

TIMEROUT waveform can be of two types:

type 1: TOUT waveform equal to a square wave

with a 50% duty-cycle

type 2: TOUT waveform equal to a pulse signal

with the pulse duration equal to the Prescaler out-

put signal.

Figure 9.3 TIMEROUT Signal Type

Prescout*Counter

Timer Output

Type1

Type2

The Timer output signal waveform type can be

selected by setting the correspondent TMRW bit

of REG_CONF6.

9.2 PWM Mode

PWM working mode is obtained by setting the cor-

respondent TMODE bit of REG_CONF5 to “1”.

TIMEROUT, in PWM Mode, consists of a signal,

with a fixed period, whose duty cycle can be mod-

ified by the user.

TIMEROUT signal is available on TOUT pin and

TIMEROUT complementary signal is available on

TOUTN pin, setting the relative bits on PORT A,

REG_CONF12[1] and REG_CONF12[2], to “0”

and REG_CONF4[6] and REG_CONF4[2] to “0”.

The PWM TIMEROUT period can be fixed by set-

ting the 16-bit prescaler output and an initial

autoreload 8-bit counter value stored in the Output

Register PWM_RELOAD, as illustrated in Figure

9.4. The Output Register PWM_RELOAD value is

automatically reloaded in the Counter when it

restarts counting.

NOTE: the Start/Stop and Set/Reset signals

should be moved together in PWM mode. If the

Start/Stop bit is reset during the PWM mode work-

ing, the TxOUT signal keeps its status until the

next start.

57/94

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