DCF77 library does not account of 40Mhz clock speed of GENERIC32MX250F128 and GENERIC32MX220F032

What steps will reproduce the problem?
1. compile and flash the the DCF77 example sketch. 
2. run it. Observe the CDC serial output for some minutes in a terminal.
3. One will see that time is not getting in sync. 

What is the expected output? What do you see instead?
Time should get in sync after at least 3 min if reception is ok. 

What version of the product are you using? On what operating system?
X.4 r713. 

Please provide any additional information below.

I had a look into dcf77.c and found that it does not handle different cpu 
clocks / 40Mhz instead of 80Mhz. 

For debugging purpose I patched dcf77.c in DCF77_start(u8 dcfPin)
at lines 280 - 284. As follows: 

    #if defined(PIC32_PINGUINO_220)||defined(GENERIC32MX250F128)||defined(GENERIC32MX220F032)
    PR1      = 6250;                    // load period register
    #else
    PR1      = 12500;                 // load period register
    #endif

This solved the issue for me. I tested that on my DIY board with a 32MX220F032.

I'm not sure if this is the best way to fix it. Maybe there is a way to query 
the clock speed and then do the math for the pre load register value.
Instead of having that hard coded.

Original issue reported on code.google.com by gerrit.b...@gmail.com on 24 Feb 2013 at 4:05

Robotonics / pinguino32

DCF77 library does not account of 40Mhz clock speed of GENERIC32MX250F128 and GENERIC32MX220F032 #39