serial connection with propeller

newmi · 2008-11-13 11:29

hi
i have a problem.
im using the propeller in combination with the netburner from parallax.
there is a serial connection between the 2 boards (using the FullDuplexSerial object). the communication from the propeller to the netburner works perfect. the same with communication between a pc and the netburner. but i cant recieve data with the propeller. i get random data i think, if connected with the netburner, and i get nothing, if connected with a pc.
here a piece of spin-code:

OBJ
   sio:    "FullDuplexSerial" 
PUB func
  sio.start(0,1,3,7800)
  waitcnt(cnt+10000000)    
  sio.str(@welcome)                 'works perfect.
  waitcnt(cnt+1000000)
  string2:=" "
  rxbuf:=" "
  repeat while rxbuf<>43          'the answer has to be "you are welcome+", so i want to have "hallo+" in string2
    rxbuf:=sio.rx
    waitcnt(cnt+10000000)   
    sio.tx(43)                            'for debugging reasons i echo the incoming byte.
    string2+=rxbuf                    'via netburner i get ² or ascii nr.3 or something like that.
  repeat                                   'with a pc connected, i get no answer
    waitcnt(cnt+1)

DAT
        welcome byte "PROP-ROBOTART+"
        rxbuf byte
        string2 byte "hallo",0

this is my "answer code"
i dont think that here is the problem ! Because i can interact with the netburner and a pc as i want to !

int fdserial = OpenSerial(1,2400,1,8,eParityNone);
    buff="";
    while (buffer[noparse][[/noparse]0]!='+'){
        read(fdserial, buffer, 1);
        buff=buff+buffer[noparse][[/noparse]0];
    }
    if(!registered && buff=="PROP-ROBOTART+"){         //anmeldung
        iprintf("Prop-RobotArt tries to log in\n");
        write(fdserial, "you are welcome+",16);
        iprintf("Prop-RobotArt is welcome\n");
        registered=true;
    }
    while (1){
        read(fdserial, buffer, 1);
        iprintf("%c",buffer);
    }

thanks

StefanL38 · 2008-11-13 13:03

Hello Newmi,

first thing I see is that the propeller-code uses a buadrate of 7800 really strange

your answercode in c uses a baudrate of 2400 that does not fit. They have to have both the same baudrate

in your propellercode the prop runs with the internal oscillator at 11-13 MHz. This gives no accurate timing you have to add
the following lines at the top of your code

  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000

which will setup the clock of the prop to 80MHz

bbest regards

Stefan

newmi · 2008-11-13 13:45

hi,
i use:
_CLKMODE = XTAL1 + PLL16X
_XINFREQ = 16_000_000

and 7800 is 2400*3,2.

in the original code the _XINFREQ = 5_000_000, so 16_000_000 is 3,2*5_000_000.

sio.str() and sio.tx() works perfect. thats not the problem.

but, anyway. thx
hope for more reactions [noparse]:D[/noparse]

Sapieha · 2008-11-13 13:56

Hi newmi

It is not posible to run Propeler with that frequency
In my tests last reliable frequency is Crystal 14.318.180 from old PC VGa kort and
not posible to run it with PLL16x. With 15MHz Crystal and PLL8x Propeler have problem and not posible to run it with PLL16x

_CLKMODE = XTAL1 + PLL8X
_XINFREQ = 14_318_180

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Nothing is impossible, there are only different degrees of difficulty.
For every stupid question there is at least one intelligent answer.
Don't guess - ask instead.
If you don't ask you won't know.
If your gonna construct something, make it·as simple as·possible yet as versatile as posible.

Sapieha

newmi · 2008-11-13 14:37

hm, ok. i can say. it definetely runs [noparse];)[/noparse] but there are a lot of problems, which are not logical.
i'll try another freq tomorrow. thx

StefanL38 · 2008-11-13 19:47

Hello newmi,

I bet the problems were caused by your overclocking

what would happen in the worst case if you use

_clkmode = xtal1 + pll16x
_xinfreq = 5_000_000 ????

what serious reason do you have to use

_clkmode = xtal1 + pll16x
_xinfreq = 16_000_000 ????

256 MHz is far outside from specification !!

best regards

Stefan

newmi · 2008-11-14 11:11

ok, i changed the freq:

_CLKMODE = XTAL1 + PLL16X
_XINFREQ = 5_000_000

sio.start(0,1,2,2400)

but nothing changed. i have still the same problem.
send data works, receiving doesnt [noparse]:([/noparse]

sio.str(@welcome)  'works
rxbuf:=sio.rx  
sio.tx(@rxbuf)      'doesnt work.

what do i do wrong?

Ariba · 2008-11-14 12:21

newmi

1) is it intended that you invert the TX line, but not the RX ? (you've set mode 2 = %0010 at sio.start).
2) Spin does not support String handling in the way you use it in the first example (string2 += rxbuf). You have to work with byte arrays for strings (something like string2[noparse][[/noparse]i++] := rxbuf) and the string2 must be declared big enough for the max. possible length.

Andy

serial connection with propeller

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