
2003 Microchip Technology Inc.
Preliminary
DS40300C-page 73
PIC16F62X
The data on the RB1/RX/DT pin is sampled three times
by a majority detect circuit to determine if a high or a
low level is present at the RX pin. If bit BRGH
(TXSTA<2>) is clear (i.e., at the low baud rates), the
sampling is done on the seventh, eighth and ninth
is set (i.e., at the high baud rates), the sampling is done
on the 3 clock edges preceding the second rising edge
FIGURE 12-1:
RX PIN SAMPLING SCHEME. BRGH = 0
FIGURE 12-2:
RX PIN SAMPLING SCHEME, BRGH = 1
FIGURE 12-3:
RX PIN SAMPLING SCHEME, BRGH = 1
RX
baud CLK
x16 CLK
START bit
Bit0
Samples
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
Baud CLK for all but START bit
(RB1/RX/DT pin)
RX pin
baud clk
x4 clk
Q2, Q4 clk
START Bit
Bit0
Bit1
First falling edge after RX pin goes low
Second rising edge
Samples
1
2
3
4
1
2341
2
RX pin
Baud CLK
x4 CLK
Q2, Q4 CLK
START Bit
Bit0
First falling edge after RX pin goes low
Second rising edge
Samples
12
3
4
Baud CLK for all but START bit