Communication between PC and PIC16f876

[knsteam]

Hello

My project and to make a billposter unwinding, who shows what I send it of the PC.

Here is my problem I have to pass on a message (thus characters) of the PC towards a PIC16F876 via the connection RS232.

To send characters I use an interface Visual Basic and as composing of change of signals (+10 /-10V - > +5 / 0V) I use a SP233ACP.
When that I look at the signals of the component there is indeed communication between both but the PIC receive that zeros or then it does not understand what I send it.

I would like to know how to connect the PIC with the PC and if you have an interface to send a mesage I am a buyer.

Thank you

KNSTEAM

[mackrackit]

Welcome to the forum.

You need to provide more information before anyone can help.

Things like:
baud rate from PC
True or Inverted
How is the PIC setup
What format are you trying to use - SERIN, SERIN2, HSERIN

Some code to see if the command is used correctly.

Maybe all of the above is correct and the PIC understands the serial input but the problem is in another place - stuck in a loop for example.

Question for you. What is a "billposter unwinding" ?

[knsteam]

Hello Dave

Baud rate from PC: 19200bps, No Parity, 8 bits, and 1 stop bit.

The fastest i can transfer data at is 9600bps, so i need to fool the PIC to send data faster.
I do this by saying that I have a 10MHz oscillator, but in fact i am using a 20MHz oscillator. By doing this, everything will run twice as fast, therefore, 9600*2=19200.

Program:

' C O M M U N I C A T I N G W I T H T H E C O M P U T E R '


PCtalk:
i = 0 : pause 100
CTS = 1

SERIN PORTA.4,N9600,["@"],char

getserial:

Serin PORTA.4,N9600,char

write i, char


if char = EOM then
CTS = 0
Goto start
endif

i = i + 1

goto getserial


I hope to have given more information and that you can help me.
Excuse me for my English (I am French).

Knsteam

[skimask]

SERIN PORTA.4,N9600,["@"],char

Look thru the '876 datasheet...see if you can find anything special about PortA.4.

[mackrackit]

Look at this
http://www.picbasic.co.uk/forum/showthread.php?t=561

Playing with the clock speed might work, but I think you are asking for problems doing this.

Why not slow the VB program dow to 9600 or use the SERIN2/SEROUT2 command at the PIC. 19200bps is supported with SERIN2/SEROUT2.

[mister_e]

My 2 cents... why using SERIN anyways as this PIC have a built-in USART?

For once Skimask says a nice pointer...

ADCON1=7

Should help a little bit

Ca devrais marcher