View previous topic :: View next topic |
Author |
Message |
Rohit de Sa
Joined: 09 Nov 2007 Posts: 282 Location: India
|
CC2500 RF modules |
Posted: Tue Dec 07, 2010 10:02 am |
|
|
I've been thinking of purchasing the TI/Chipcon CC2500 2.4GHz RF modules found here http://allsensor.in/shop/product_info.php?cPath=56&products_id=158
I'd like to interface this to an '877A. From the reading I've done I've come to the conclusion that the CC2500 and the CC1100 are pretty similar (the only difference lies in the values of a few configuration registers). So this code ( http://www.ccsinfo.com/forum/viewtopic.php?t=29114&highlight=chipcon ) should work, right? A forum search reveals that not many people use this chip (or that I am one of the very few who are having difficulty with it! :-P)
Additionally, the CC2500 is a 1.8v-3.6v chip. Is it possible for me to interface it to the 5v outputs of the PIC without using a level translator? I would use series resistors on the SDI/reset/CS pins in the *hope* that the internal diodes of the CC2500 clamp the voltage to safe levels. The problem is that the CC2500/CC1100 datasheets make no mention whatsoever of the I/O equivalent diagrams. Would it be wrong to assume that the CC2500 is equipped with such clamping diodes?
CC2500 datasheet: http://www.ti.com/lit/gpn/cc2500
Rohit |
|
|
FvM
Joined: 27 Aug 2008 Posts: 2337 Location: Germany
|
|
Posted: Tue Dec 07, 2010 10:27 am |
|
|
Quote: | Would it be wrong to assume that the CC2500 is equipped with such clamping diodes? |
No, any standard digital IO of a CMOS IC has it. With mixed signal IC, there may be a problem of causing leakage currents that affect analog circuit parts, although I won't expect it here. But I tend to place a voltage divider instead of a simple series resistor, that avoids forward biasing the diodes. |
|
|
Rohit de Sa
Joined: 09 Nov 2007 Posts: 282 Location: India
|
|
Posted: Tue Dec 07, 2010 10:54 am |
|
|
Thanks for the quick response, Frank. So resistive divider it is!
I'm surprised no one's uploaded a CC1100/CC2500 driver yet. Guess I'll be the one to do so! :-P
Rohit |
|
|
|