PIC18F87K22 Datasheet, PDF (330/548 Pages) Microchip Technology – 64/80-Pin, High-Performance, 1-Mbit Enhanced Flash Microcontrollers with 12-Bit A/D and nanoWatt XLP Technology

PIC18F87K22 FAMILY
EXAMPLE 22-1: CALCULATING BAUD RATE ERROR
For a device with FOSC of 16 MHz, desired baud rate of 9600, Asynchronous mode, and 8-bit BRG:
Desired Baud Rate = FOSC/(64 ([SPBRGHx:SPBRGx] + 1))
Solving for SPBRGHx:SPBRGx:
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%
TABLE 22-2: REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
TXSTA1
CSRC
TX9
TXEN
SYNC
SENDB BRGH
RCSTA1
SPEN
RX9
SREN
CREN
ADDEN
FERR
BAUDCON1
ABDOVF RCIDL
RXDTP
TXCKP
BRG16
—
SPBRGH1
EUSART1 Baud Rate Generator Register High Byte
SPBRG1
EUSART1 Baud Rate Generator Register
TXSTA2
CSRC
TX9
TXEN
SYNC
SENDB BRGH
RCSTA2
SPEN
RX9
SREN
CREN
ADDEN
FERR
BAUDCON2
ABDOVF RCIDL
RXDTP
TXCKP
BRG16
—
SPBRGH2
EUSART2 Baud Rate Generator Register High Byte
SPBRG2
EUSART2 Baud Rate Generator Register
PMD0
CCP3MD CCP2MD CCP1MD UART2MD UART1MD SSP2MD
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the BRG.
Bit 1
TRMT
OERR
WUE
TRMT
OERR
WUE
SSP1MD
Bit 0
TX9D
RX9D
ABDEN
TX9D
RX9D
ABDEN
ADCMD
DS39960B-page 330
Preliminary
 2010 Microchip Technology Inc.