PIC18F67J11-IPT Datasheet, PDF (276/448 Pages) Microchip Technology – 64/80-Pin High-Performance, 1-Mbit Flash Microcontrollers with nanoWatt Technology

PIC18F87J11 FAMILY
EXAMPLE 20-1: 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 20-2: REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2 Bit 1
TXSTAx
CSRC
TX9
TXEN SYNC SENDB BRGH TRMT
RCSTAx
SPEN
RX9
SREN CREN ADDEN FERR OERR
BAUDCONx ABDOVF RCIDL RXDTP TXCKP BRG16
—
WUE
SPBRGHx EUSARTx Baud Rate Generator Register High Byte
SPBRGx EUSARTx Baud Rate Generator Register Low Byte
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the BRG.
Bit 0
TX9D
RX9D
ABDEN
Reset Values
on Page:
59
59
61
61
61
DS39778D-page 276
© 2009 Microchip Technology Inc.