PC serial port funny

[HenrikOlsson]

Hi,
I think yoyr problem is in your DEBUG statements in the PIC code. If you use the #modifier the PIC sends the the value of the variable as "text". So if the varaible lower is a word and set to 1234 the pic will send four bytes ie. "1","2","3","4" instead of the two bytes that the wordvariable consists of. That way the number of bytes the PIC sends depends on the actuall value of the variables so the OnComm() event will fire at different places in your "stream" since it's set to fire after every 6 bytes.

I think that you need to do:

sendlower:
debug "aa", lower
PAUSE 100

And then on the VB-side you look for "aa" and then extract the high and low byte from the stream and put them together with Result = highbyte*256+lowbyte or something like that.

Did it make any sence?

/Henrik Olsson.

[nicjo]

Thanks Henrik,

Yes I have tried what you've suggested, but only on the transmission of one variable containing 2 bytes. It worked fine. I will change the code and see if that does the trick. Ithink it might be a little tricky though.


John.

[nicjo]

Hi all,

I've been able to get error free comms by sending the variables as high and low bytes (debug "aa", stepcnt.byte1, stepcnt.byte0). The same is not true when I send the variable as

DEBUG "aa", stepcnt

My steps taken to covert for display;

cmdword = Left(displaystr, 2) ' rip out the command 'aa'
newstring = asc(mid$, 3, 2)) ' put the rest of the word into var
Lbyte = newstring AND &H255
Hbyte = (newstring - Lbyte) / &H100
word = (Hbyte * &H100) OR Lbyte
Text.text=word

This seems to work on paper. I've also swapped high and low around as I think the PIC sends the low order byte first?

Even though I've got the project working well, could someone explain the correct way to strip data using VB.

Most appreciated

John

[mister_e]

Could you post your whole codes here (all VB(Vbp,form...) and PBP.Bas)? just pack both in a zip. Save me to re-invent the wheel and work exactly with what you have

My single brain cell simply can't work with scratch and partial code snip... sorry i'm getting old

[nicjo]

Steve, I've attached the VB program and the PBP prog. Its pretty uglgy but for the best part it works. Its works well with the vb prog when variables are sent as byte1, byte2. Strange this occur when the variable is sent eg HSEROUT ["aa", stepcnt].
I also changed to the USART as I found using the serial commands I could not catch external inputs.

Thanks for your time Steve,

John

[mister_e]

O.K. i'll look at that. So you're using a 16F628 right? for serial comm, i would suggest you to use a crystal. To make sure to don't miss incoming stuff, i always suggest to use a USART interrupt.

this

["aa", stepcnt]

can't work because it will send a WORD ascii character... wich is impossible. So instead, you should work around and use

["aa", #stepcnt]

but use VAL on the VB side.

I'll do a little something here, totally different, so you could use some part of it in your actual code.

[nicjo]

Thanks, I,m using a Xtal, found that out the hard way, could'nt work out why there were so many errors, after puting xtal in cct, errors disappeared. And yes, I'm using a 628.

I kind of figured that "aa" stepcnt was a word representation of stepcnt and that on the other end it would need to be split in two to find the original values. I started off with #stepcnt but on the vb side after sending a whole bunch of words, errors started appearing. Never thought of the VAL function though. I just placed the value from the PIC straight into a txt box. Anyway, I hope my code is not to painfull.

Thanks again

John