Serial data problem

**mister_e** · - 2nd December 2007, 02:32

which PC software do it?

Are you sure it's 9600 baud and not 250,000 bauds?

So basically it's always a 1+1+16 = 18 data stream?

If so, did you tried with a HSERIN loop? just for debuggig purpose.

Code:

DataByte VAR BYTE[18]

HSERIN [STR DataByte\18]
If DataByte[0]= 255 then DoSomething

**The Master** · - 2nd December 2007, 02:35

Im sure the PC software is setup correctly. I can change the address of the chip fine (that only takes 2 bytes). The PC software works on other chips too.

I think im gonna try a different aproach. Im going to buffer all the incoming data as fast as i can then deal with it every half cycle

Edit: Yes, 18 bytes for control. 2 bytes for an address reset. When sending 18 bytes it misses out 1-3 bytes

**The Master** · - 2nd December 2007, 03:06

I just tried some test code out

Code:

'The main loop
loop:
    
    'Check for serial data
    if pir1.5=1 then 'Check if there is any serial data
        while pir1.5 'Loop through all the data
            indata=RCREG 'Get a byte
            select case indata
                case 255 'Reset the buffer
                    recpos=0
                case else
                    if recpos<17 then
                        inbuffer(recpos)=indata
                        recpos=recpos+1
                    else
                        high porta.1
                    endif
            end select
        wend
        if rcsta.1=1 then
            rcsta.4=0
            rcsta.4=1
        endif
    endif
goto loop

Now, that code *should* wait for a 255. When it gets it it resets recpos to 0. Each byte after that should end up in InBuffer until recpos=17. At that point a light should turn on (porta.1)

The reset part does seem to be working but not all the bytes arrive. The light wont come on until i send another 1-3 bytes.

I should point out im not using the MAX232 chip because they havnt arrived yet but instead i linked into one of Matts boxes which has an alternative solution. I cant see why that would cause a problem but ive just found out that when i set the address it gets set to 1 less than what i actually set it to

**The Master** · - 2nd December 2007, 04:24

Woo. Its all working

Ive only got 1 output working at the moment though. Ive got to put a loop in to handle all outputs and ive got to put the set address code back in but as it is the attached code is working perfectly.

I only have 1 small problem with it. If i send data too fast then the light flickers slightly. Not enough to be annoying but i doubt the PC would ever send commands that fast anyway