
2009 Microchip Technology Inc.
DS39636D-page 201
PIC18F2X1X/4X1X
FIGURE 17-1:
AUTOMATIC BAUD RATE CALCULATION
FIGURE 17-2:
BRG OVERFLOW SEQUENCE
BRG Value
RX pin
ABDEN bit
RCIF bit
Bit 0
Bit 1
(Interrupt)
Read
RCREG
BRG Clock
Start
Auto-Cleared
Set by User
XXXXh
0000h
Edge #1
Bit 2
Bit 3
Edge #2
Bit 4
Bit 5
Edge #3
Bit 6
Bit 7
Edge #4
Stop Bit
Edge #5
001Ch
Note: The ABD sequence requires the EUSART module to be configured in Asynchronous mode and WUE = 0.
SPBRG
XXXXh
1Ch
SPBRGH
XXXXh
00h
Start
Bit 0
XXXXh
0000h
FFFFh
BRG Clock
ABDEN bit
RX pin
ABDOVF bit
BRG Value