#FUSES for the PICF2550

If you are:

• Programming using the CCS compiler.
• Using the PIC18F2550
• Loading the firmware using the WinPic800
• Your Xtal is 20MHz

Then, in order for everything works fine when programming the RS232 module, you have to, either, change the parameters as showed in the below figure every time you load the firmware or define the FUSE directive as follows:

#fuses HS,NOWDT,NOPROTECT,PLL5,CPUDIV1

PLL5: defines the oscillator selection to 20MHz

CPUDIV1: Avoid a postscaler of the main clock “CPU system clock”

This issue made me waste a lot of time because my RS232 model was not working as expected using the CCS compiler but using the Mikro C compliler everything worked fine. Until I changed these parameters.