UART.bas getting weird symbol???

[mike20200]

Im using PIC 16F877A with 20MHZ crystal

and the UART.bas
================================================== ==================
define OSC 20

B1 var byte

TRISC = %10111111 ' Set TX (PortC.6) to out, rest in
SPBRG = 25 ' Set baud rate to 2400
RCSTA = %10010000 ' Enable serial port and continuous receive
TXSTA = %00100000 ' Enable transmit and asynchronous mode

'Echo received characters in infinite loop
loop: Gosub charin ' Get a character from serial input, if any
If B1 = 0 Then loop ' No character yet

Gosub charout ' Send character to serial output
Goto loop ' Do it forever

' Subroutine to get a character from USART receiver
charin: B1 = 0 ' Preset to no character received

If PIR1.5 = 1 Then ' If receive flag then...
B1 = RCREG ' ...get received character to B1

'high PORTB.5
'pause 200
'low PORTB.5
'pause 200
Endif

ciret: Return ' Go back to caller

' Subroutine to send a character to USART transmitter
charout: If PIR1.4 = 0 Then charout ' Wait for transmit register empty

TXREG = B1 ' Send character to transmit register

'high PORTB.4
'pause 200
'low PORTB.4
'Pause 200

Return ' Go back to caller
================================================== =================

However what ever i type in like ABCD then the HYPERTERMINAL will return back some funny symbol can anyone help me???

[paul borgmeier]

Try your code with a 4MHz Xtal and it will (most likely) work. Because you are using a 20 MHz Xtal and not a 4 MHz Xtal, you will need to change your SPBRG value - see Table 10.3 in the datasheet for the 877A.

[mike20200]

thx alot. I will try to change the SPBRG to 129 for 2400 baud rate (20MHZ XTAL).

[mike20200]

Thx paul borgmeier for pointing out my careless mistake. Now everything is working fine