Serial Communication with PIC16F877A

[mcbeasleyjr]

Hello again to all... I am testing pieces of code that I have put together from various sources. I am trying to get a communications link set up between my PIC16F877A and my PC. I am using the serial communicator that comes with MicroCode Studio Plus. If I understand what I'm trying to do correctly, the PIC should wait for a message from the PC. If it doesn't receive this message, it will timeout and is supposed to display "nada". However, when I don't send anything to the PIC, it returns 4 wierd looking symbols. Also, if I try to transmit something to PIC, it doesn't return anything at all. Any helpful advice would be greatly appreciated.

DEFINE OSC 20

INCLUDE "MODEDEFS.BAS"
DEFINE HSER_BAUD 9600   ' HSER baud rate
DEFINE HSER_SPBRG 129   ' HSER SPBRG init
DEFINE HSER_RCSTA 90h   ' HSER receive status init
DEFINE HSER_TXSTA 24h   ' HSER transmit status init high speed
'DEFINE HSER_EVEN 1      ' Use only if even parity is desired
'DEFINE HSER_ODD 1       ' Use only if odd parity is desired
DEFINE HSER_BITS 9      ' Use for 8 bits ''+ parity
DEFINE HSER_CLROERR 1   ' Automatically clear HSERIN overflow errors

TRISC=%10000000

TimeDate VAR BYTE[6]

Main:
    HSERIN 5000,TimeOut,[WAIT("A"),STR TimeDate\6]  ' A369621
    HSEROUT ["Rcvd string: ", STR TimeDate\6,13,10]    
    GOTO Main
            
TimeOut:
    HSEROUT ["Nada",13,10]
    GOTO Main

Port Settings:
COM1
9600 Baud
No Parity
Byte Size is 8
1 Stop Bit

[mackrackit]

Do you have a MAX232 or similar between the PIC and PC?

If you do not have one, try SERIN2/SEROUT2 using inverted mode.

[mcbeasleyjr]

Yes I have a MAX232 on the ICD I've built... it should also work as my serial communicator for this purpose as well... This is the number on the chip:

69CT01M
MAX232IN

TTL to CMOS converter...

any ideas?

[Darrel Taylor]

Serial data to a PC should always be 8 bits.

DEFINE HSER_BITS 9 ; won't work
<br>

[mackrackit]

Missed this the first time I looked at it.
DEFINE HSER_BITS 9
Scratch the above line

[mcbeasleyjr]

I have scratched the line as you suggested... however, it still isn't working. If I try to transmit the example in my code, which is A369621... I don't receive anything back at all. Also, if I don't transmit anything and the USART times out, I receive this: ¬ºê*ë... any other ideas?

Do I have to set PORTC as this:????

TRISC=%11000000

I'm a little confused on the correct settings to get the USART to function properly.

[mackrackit]

Maybe this will help.
http://www.melabs.com/resources/samples/pbp/usart.bas