Datasheet

Table Of Contents
PIC18F2221/2321/4221/4321 FAMILY
DS39689F-page 216 © 2009 Microchip Technology Inc.
EXAMPLE 19-1: CALCULATING BAUD RATE ERROR
TABLE 19-2: REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
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%
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 RXDTP TXCKP 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 as0’. Shaded cells are not used by the BRG.