Can I directly connect PIC16F873 output to RS232 without using a max232?

[Cleong]

can i know that if i use a pic16f873 trasmit an output, can i straightly connect the pic output to rs 232 without using a max232 ?

the form that VB(rs 232) can read is in hex or binary?
for example,
if my output is 00001111 then i need convert it to h'8' just send out the result or can straight away send in binary form???

the vb can only read Hex form ??

 

[roykyn]

Re: help

you have to use max 232......cos the bus voltage r different.....

 

[budhy]

Re: help

can i know that if i use a pic16f873 trasmit an output, can i straightly connect the pic output to rs 232 without using a max232 ?

PIC16F873 run on 0/5 Volt logic level, RS232 run on +12/-12 Volt. MAX232 is a voltage translator to translate the difference voltage level of the two system.

You have to use MAX232 to interface PIC16F873 to RS232 lines.

the form that VB(rs 232) can read is in hex or binary?
for example,
if my output is 00001111 then i need convert it to h'8' just send out the result or can straight away send in binary form???

the vb can only read Hex form ??

Cleong, please mention Hexadecimal data is just another form of binary data, so hexadecimal is equivalent to binary!

On digital computer, all data are digital (binary) data, depend on how we treat it, it can be a ASCII character data or a decimal value data.

As a ASCII character, binary value 00001111 is SI (select in) charater.
As a decimal value data, binary value 00001111 is 15 (decimal)!

It depend on the way you read the serial port!

 

[mamsamae]

Re: help

for the using of MAX232 the follows' answer is suffient. for the reading using VB there are 2 mode of reading or writing

1- binary mode
which read and write in hex format i.e, 0xh4.

2- string mode

for example if u write 'A' to the serial port , VB convert it to hex 0x41 then send it

i attach a file that will help u in programming.

 

[budhy]

Re: help

1- binary mode
which read and write in hex format i.e, 0xh4.

This is the decimal value data as I mean

2- string mode
for example if u write 'A' to the serial port , VB convert it to hex 0x41 then send it

To use string mode, before you send your 4 bit data to PC RS232 port, OR-ed you 4 bit data with 0x40 (or add it with 64 decimal). At this case you will receive character '@', 'A', 'B' .... or 'O', this character represent your temperature value 0, 1, 2, ... or 15.