PIC18F87K90 Datasheet, PDF (352/566 Pages) Microchip Technology – 64/80-Pin, High-Performance Microcontrollers with LCD Driver and nanoWatt XLP Technology

PIC18F87K90 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
Bit 1
TXSTA1
CSRC
TX9
TXEN SYNC SENDB BRGH TRMT
RCSTA1
SPEN
RX9
SREN CREN ADDEN FERR OERR
BAUDCON1 ABDOVF RCIDL RXDTP TXCKP BRG16
—
WUE
SPBRGH1 EUSART1 Baud Rate Generator Register High Byte
SPBRG1 EUSART1 Baud Rate Generator Register Low Byte
TXSTA2
CSRC
TX9
TXEN SYNC SENDB BRGH TRMT
RCSTA2
SPEN
RX9
SREN CREN ADDEN FERR OERR
BAUDCON2 ABDOVF RCIDL RXDTP TXCKP BRG16
—
WUE
SPBRGH2 EUSART2 Baud Rate Generator Register High Byte
SPBRG2 EUSART2 Baud Rate Generator Register Low Byte
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the BRG.
Bit 0
Reset Values
on Page:
TX9D
75
RX9D
75
ABDEN
77
74
75
TX9D
79
RX9D
79
ABDEN
79
80
80
DS39957B-page 352
Preliminary
 2010 Microchip Technology Inc.