Datasheet

Table Of Contents
PIC18F2480/2580/4480/4580
DS39637D-page 236 © 2009 Microchip Technology Inc.
EXAMPLE 19-1: CALCULATING BAUD RATE ERROR
TABLE 19-2: REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reset
Values
on Page:
TXSTA
CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 57
RCSTA SPEN
RX9 SREN CREN ADDEN FERR OERR RX9D 57
BAUDCON
ABDOVF RCIDL SCKP BRG16 WUE ABDEN 57
SPBRGH EUSART Baud Rate Generator Register High Byte 57
SPBRG EUSART Baud Rate Generator Register Low Byte 57
Legend: — = unimplemented, read as ‘0. Shaded cells are not used by the BRG.
For a device with FOSC of 16 MHz, desired baud rate of 9600, Asynchronous mode, 8-bit BRG:
Desired Baud Rate = F
OSC/(64 ([SPBRGH:SPBRG] + 1)
Solving for SPBRGH:SPBRG:
X = ((FOSC/Desired Baud Rate)/64) – 1
= ((16000000/9600)/64) – 1
= [25.042] = 25
Calculated Baud Rate = 16000000/(64 (25 + 1))
= 9615
Error = (Calculated Baud Rate – Desired Baud Rate)/Desired Baud Rate
= (9615 – 9600)/9600 = 0.16%