Post by thread:[PIC]:a/d converters

>I often use 18.432 MHz crystals on 20 MHz parts, because that divides down >to several baud rates nicely. I am using 19.6608 for the same reason, also a multiple of standard baud rate frequencies. Useful to have that extra ~1.2MHz when trying to squeeze that last bit of computing time out of it. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> >I often use 18.432 MHz crystals on 20 MHz parts, because that divides down > >to several baud rates nicely. > > I am using 19.6608 for the same reason, also a multiple of standard baud > rate frequencies. Useful to have that extra ~1.2MHz when trying to squeeze > that last bit of computing time out of it. Note that all the standard baud rates can be hit within acceptable error with 20.000MHz crystal and high speed UART mode. I've used 115.2Kbaud on 20MHz PICs talking to PCs many times. The baud rate error is even smaller at slower baud rates. See my UART_BAUD macro in STD.INS.ASPIC at http://www.embedinc.com/pic for an easy way to have the assembler calculate all the baud rate particulars, including selection of low/high speed mode. ******************************************************************** Olin Lathrop, embedded systems consultant in Littleton Massachusetts (978) 742-9014, spam_OUTolinTakeThisOuTembedinc.com, http://www.embedinc.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics