ST92T195 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST92T195

48-96 Kbyte ROM HCMOS MCU WITH ON-SCREEN DISPLAY AND TELETEXT DATA SLICER

STMicroelectronics 

ST92195C/D - STANDARD TIMER (STIM)

7.2 STANDARD TIMER (STIM)

Important Note: This chapter is a generic descrip-

tion of the STIM peripheral. Depending on the ST9

device, some or all of the interface signals de-

scribed may not be connected to external pins. For

the list of STIM pins present on the particular ST9

device, refer to the pinout description in the first

section of the data sheet.

7.2.1 Introduction

The Standard Timer includes a programmable 16-

bit down counter and an associated 8-bit prescaler

with Single and Continuous counting modes capa-

bility. The Standard Timer uses an input pin (STIN)

and an output (STOUT) pin. These pins, when

available, may be independent pins or connected

as Alternate Functions of an I/O port bit.

STIN can be used in one of four programmable in-

put modes:

– event counter,

– gated external input mode,

Figure 46. Standard Timer Block Diagram

n

– triggerable input mode,

– retriggerable input mode.

STOUT can be used to generate a Square Wave

or Pulse Width Modulated signal.

The Standard Timer is composed of a 16-bit down

counter with an 8-bit prescaler. The input clock to

the prescaler can be driven either by an internal

clock equal to INTCLK divided by 4, or by

CLOCK2 derived directly from the external oscilla-

tor, divided by device dependent prescaler value,

thus providing a stable time reference independ-

ent from the PLL programming or by an external

clock connected to the STIN pin.

The Standard Timer End Of Count condition is

able to generate an interrupt which is connected to

one of the external interrupt channels.

The End of Count condition is defined as the

Counter Underflow, whenever 00h is reached.

INEN INMD1 INMD2

STIN1

INPUT

&

(See Note 2) CLOCK CONTROL LOGIC

INTCLK/4

CLOCK2/x

STOUT1

EXTERNAL

INTERRUPT1

MUX

STANDARD TIMER

CLOCK

STP

8-BIT PRESCALER

STH,STL

16-BIT

DOWNCOUNTER

OUTMD1 OUTMD2

END OF

COUNT

OUTPUT CONTROL LOGIC

INTERRUPT

CONTROL LOGIC

INTS

Note 1: Pin not present on all ST9 devices.

INTERRUPT REQUEST

Note 2: Depending on device, the source of the INPUT & CLOCK CONTROL LOGIC block

may be permanently connected either to STIN or the RCCU signal CLOCK2/x. In devices without STIN and CLOCK2, the

INEN bit must be held at 0.

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