
PIC18F1230/1330
DS39758D-page 152
2009 Microchip Technology Inc.
EXAMPLE 15-1:
CALCULATING BAUD RATE ERROR
TABLE 15-2:
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
=
FOSC/(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
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
BAUDCON ABDOVF
RCIDL
RXDTP
TXCKP
BRG16
—
WUE
ABDEN
SPBRGH
EUSART Baud Rate Generator Register High Byte
SPBRG
EUSART Baud Rate Generator Register Low Byte
Legend:
— = unimplemented, read as ‘0’. Shaded cells are not used by the BRG.