RF12 module need to convert some C to Basic

[davewanna]

on first turn-on, the RFM12 outputs a 1Mhz osc for the pic, which I am putting in on OSC1.
After I write the command ... dout = $C0F7 : gosub Writecmd ... this changes that osc freq from 1MHz to 10MHz... so my pic will run at 10MHz. I have figured out the problem to just be that my crystal setting was on XT, not HS.

I am onto the next part of converting C to Basic if anyone dare to assist....

void WriteFSKbyte( uchar DATA )
{
  uchar RGIT=0;
  uint temp=0xB800;
  temp|=DATA;
Loop: SCK = 0;
  nSEL=0;
  SDI=0;
  SCK=1;
  if(SDO)         //polling SDO
  {
    RGIT=1;
  }
  else
  {
    RGIT=0;
    WriteCMD(temp);
  }
}

So far I have...

WriteFSKbyte:
temp = $B800

Loop:
SCK = 0
nSEL = 0
SDI = 0
SCk = 1
if SDO = 1 then
  rgit = 1
else
  rgit = 0
endif
SCK = 0
SDI = 1
nSEL = 1
if rgit = 0 then
  goto loop
endif
rgit = 0
dout = temp
gosub writecmd
return

The part I am struggling with right now is...

  uchar RGIT=0;
  uint temp=0xB800;
  temp|=DATA;

Does this take bit 0 of DATA and stick it to temp somehow??

Someone with some C knowledge please help me!

Thanks!

[Ioannis]

Why are you compilcating things?

Just put a crystal or resonator on the pic and have it working on a precise time base. What you are doing now is screwing the timing of the commands and may be locks the pic at the time the freq. is changing. Also at 4MHz and lower the PIC should use XT settings and above that HS settings.

I strongly recommend the PIC using its own clock.

Ioannis

[davewanna]

This is mostly just an excercise for a project of mine. The way the module is toted, is that it can output a clock signal for the pic, so only the crystal on the module is needed, and not 2 seperate oscillators. The examples I have seen of this module being used in the real world have had the osc out line connected to the pic. I have now got this part working though, and it is not a problem.

Cheers

[dhouston]

Do you have to reset the registers each time the RF12 starts or are they non-volatile so that the clock frequency will always be 10MHz (or whatever) once set? In my experience, registers like these are usually non-volatile.

[Bruce]

uchar RGIT=0; unsigned char RGIT = 0
uint temp=0xB800; unsigned int temp = B800 hex
temp|=DATA; temp = temp ORed with the value in DATA

[davewanna]

dhouston,

So far the registeres are reset when the power is removed. i.e. everytime I restart the module, the OSC is back to 1MHz.

I did read in one of the datasheets, but I can't find it now, something along the lines of that you have to reset the module after changing settings for them to be stored. Not 100% sure of this right now. But I haven't had any luck attempting it so far.


Bruce,

What do you mean ORed?

I'm struggling to get the over-all picture of what it sends here.

From my understanding.. to actually send data.. I must use the "WriteCMD loop from earlier, to send first $b8, and then another 8bits of data.

Which I have done by...

WriteFSKbyte:
...
temp = $b8
SCK = 0
SDI = 1
nSEL = 1
dout.highbyte = temp
dout.lowbyte = dat
gosub writecmd

Now currently there is what I presume is a preamble..

  dout = $8228            'open PA
  gosub writecmd
  pauseus 4
  dout = $8238            'something to do with transmit register
  gosub writecmd
  pauseus 2
  dat = $AA
  gosub writefskbyte    'send $B8AA
  gosub writefskbyte    'send $B8AA
  dat = $2D
  gosub writefskbyte    'send $B82D
  dat = $D4
  gosub writefskbyte    'send $B8D4

That should actually transmit.... "$AAAA, $2DD4 " ????????

Suffering from severe lack of experience in RF and/or serial transmission, when should I send the pre-amble? Before every transmission?

i.e.
Preamble,
Transmit data, - Several 16bit segments...
Pause
do whatever else..
Preamble
Transmit data
etc??

[skimask]

I did read in one of the datasheets, but I can't find it now, something along the lines of that you have to reset the module after changing settings for them to be stored. Not 100% sure of this right now. But I haven't had any luck attempting it so far.

Don't see anything about that.

What do you mean ORed?

Logical OR'ing. It's in the manual, or look it up on Wiki under Boolean logic.

I must use the "WriteCMD loop from earlier, to send first $b8, and then another 8bits of data.

ShiftIn/ShiftOut will work just fine with this chip, no need to reinvent the wheel as you have been doing.