Data corrupterd when using serout command

dear all,

I have some problems dealing with interfacing between pic16f628a and pc's hyper-terminal. My code is as follow:




INCLUDE "modedefs.bas"
testvalue var byte
pause 3000

'
'other code
'
'

SEROUT PORTB.2,T2400,["hello"] 'sending the string "hello"
SEROUT PORTB.2,T2400,["123"]
SEROUT PORTB.2,T2400,["abc"]

main:
serin PORTB.1,T2400,testvalue 'waiting for 1 byte of data and store it
'in testvalue
SEROUT PORTB.2,T2400,[testvalue]
goto main



Whenever I power up my PIC, the 1st byte of data sent will be corrupted(which shown in hyper terminal), however the rest of the data are correct. I wonder why??? Anyone got solution???

ps: i'm using pic16f628's, tx and rx is connected to hin232




thanks,

cheer:>

There's a whole heap of reasons...

Try this...

Loop:
SEROUT PORTB.2,T2400,[REP $00\8,"hello "] 'sending the string "hello"
SEROUT PORTB.2,T2400,["123 "]
SEROUT PORTB.2,T2400,["abc",13,10]
Pause 1000
Goto Loop

Have you now got clean transmission?

Those NULS $00 sent at the start are there to push any line garbage lurking in your comms link away. Also, if you're not using a Resonator or Crystal oscillator, then 2400 baud can produce significant errors - especially at start up, and it can take a few bits for the PC's USART to sync-up if it's right at the edge of timing tollerance.

Melanie

thanks man, I am trying the way as u stated :>

hi i got some doubt:

what is the syntax "$00\8" means? I got compilation error "error line 6: expected "]", where line 6 is:

SEROUT PORTB.2,T2400,[$00\8,"hello "] 'sending the string "hello"


help please,


thanks,

Sorry, my omission of the word REP... I've corrected it.

What does REP do?
Is this in the manual?

Toni

REP c\n

Repeat character c, n times...

In the manual in at least four places... DEBUG, LCDOUT, SEROUT, SEROUT2... and in list of Reserved Words.

Thanks for pointing that out.

This is something that used to come up a lot
just before your pause 3000 put in

high portb.2

you could even change the pause 3000 to

pause 500

this should take care of all your problems

Is there a spell checker for this forum ??

Melanie,

As there are more and more questions regarding serial comunication we should put some "How To's" together and post it in the FAQ category.

There appears to be a lot of confusion about the different modes (TRUE/INVERTED), Baud rate vs. clock speed etc.

regards

Ralph

Yup, I agree. It's a question of finding time to do it all... nothing stopping other folks contributing to the FAQ... however Serial Comms is a major subject, and not something that gets covered in a couple of paragraphs and ten lines of code. Just for starters, you can do comms between two PICs a dozen different ways, and them some... it's one of those subjects that has so many variables, that what works brilliantly for one application, ends up totally inappropriate for another.

Melanie,

If there is some FTP-space on the server we could start writing a "HowTo" and share that Document using FTP.

Once we think it covers everything it will go to the FAQ section as PDF.

regards