ST6285BQ1 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST6285BQ1

8-BIT OTP/EPROM MCU WITH LCD DRIVER, EEPROM AND A/D CONVERTER

STMicroelectronics 

ST62T85B/E85B

4 ON-CHIP PERIPHERALS

4.1 I/O PORTS

The MCU features Input/Output lines which may

be individually programmed as any of the following

input or output configurations:

be also written by user software, in conjunction

with the related option registers, to select the dif-

ferent input mode options.

– Input without pull-up or interrupt

– Input with pull-up and interrupt

– Input with pull-up, but without interrupt

– Analog input

Single-bit operations on I/O registers are possible

but care is necessary because reading in input

mode is done from I/O pins while writing will direct-

ly affect the Port data register causing an unde-

sired change of the input configuration.

– Push-pull output

The Data Direction registers (DDRx) allow the

– Open drain output

data direction (input or output) of each pin to be

set.

The lines are organised as bytewise Ports.

The Option registers (ORx) are used to select the

Each port is associated with 3 registers in Data

space. Each bit of these registers is associated

) with a particular line (for instance, bits 0 of Port A

t(s Data, Direction and Option registers are associat-

ed with the PA0 line of Port A).

uc The DATA registers (DRx), are used to read the

d voltage level values of the lines which have been

ro configured as inputs, or to write the logic value of

the signal to be output on the lines configured as

P outputs. The port data registers can be read to get

te the effective logic levels of the pins, but they can

le Figure 17. I/O Port Block Diagram

bso SIN CONTROLS

RESET

different port options available both in input and in

output mode.

All I/O registers can be read or written to just as

any other RAM location in Data space, so no extra

RAM cells are needed for port data storage and

manipulation. During MCU initialization, all I/O reg-

isters are cleared and the input mode with pull-ups

and no interrupt generation is selected for all the

pins, thus avoiding pin conflicts.

VDD

Product(s) - O SHIFT

Obsolete REGISTER

DATA

DIRECTION

REGISTER

DATA

REGISTER

OPTION

REGISTER

VDD

INPUT/OUTPUT

SOUT

TO INTERRUPT

TO ADC

VA00413

33/78

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