Microchip Technology IC PIC MCU PIC18F65J15-I/PT TQFP-64 MCP PIC18F65J15-I/PT Data Sheet
Product codes
PIC18F65J15-I/PT
PIC18F87J10 FAMILY
DS39663F-page 244
© 2009 Microchip Technology Inc.
EXAMPLE 20-1:
CALCULATING BAUD RATE ERROR
TABLE 20-2:
REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset Values
on page
TXSTAx
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
RCSTAx
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
BAUDCONx ABDOVF
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
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.
For a device with F
OSC
of 16 MHz, desired baud rate of 9600, Asynchronous mode, 8-bit BRG:
Desired Baud Rate
= F
OSC
/(64 ([SPBRGHx:SPBRGx] + 1))
Solving for SPBRGHx:SPBRGx:
X
= ((F
OSC
/Desired Baud Rate)/64) – 1
= ((16000000/9600)/64) – 1
= [25.042] = 25
= [25.042] = 25
Calculated Baud Rate
= 16000000/(64 (25 + 1))
= 9615
= 9615
Error
= (Calculated Baud Rate – Desired Baud Rate)/Desired Baud Rate
= (9615 – 9600)/9600 = 0.16%
= (9615 – 9600)/9600 = 0.16%