4 usart mode 3, 9 .1 .4 usart mode 3 -7, Figure 9-4 . usart mode 3 -7 – Maxim Integrated MAXQ622 User Manual
Page 143
MAXQ612/MAXQ622 User’s Guide
Maxim Integrated
9-7
9.1.4 USART Mode 3
This mode has the same operation as mode 2, except for the baud rate source . As shown in Figure 9-4, mode 3 gener-
ates baud rates through the baud-clock generator . The bit shifting and protocol are the same .
Figure 9-4. USART Mode 3
D0
D1
D2
D3
D4
D5
D6
D7
RB8
STOP
D0
D1
D2
D3
D4
D5
D6
D7
TB8
STOP
RECEIVE TIMING
TRANSMIT TIMING
BAUD
CLOCK
DIVIDE
BY 4
D7
D6
D5
D4
D3
D2 D1
D0
0
1
LOAD
CLOCK
TRANSMIT SHIFT REGISTER
S0
LATCH
RECEIVE DATA BUFFER
WR
SBUF
RD
D7
D6
D5
D4 D3 D2
D1
D0
CLOCK
RECEIVE SHIFT REGISTER
SI
RESET
LOAD
SERIAL
BUFFER
LOAD
SERIAL I/O
CONTROL
INTS
SHIFT
READ
SERIAL
BUFFER
TI
FLAG =
SCON.1
RI
FLAG =
SCON.0
DIVIDE
BY 16
LDSBUF
RDSBUF
0
1
SBUF
SMOD
RXD
PIN
SYSTEM
CLOCK
DIVIDE
BY 16
BIT
DETECTION
TXD
PIN
BAUD-CLOCK
GENERATOR
START
STOP
START
SERIAL
INTERRUPT
DATA BUS
TB8 =
SCON.3
D8
RB8 =
SCON.2
D8
STOP
LDSBUF
SHIFT
TI
TXD
SHIFT
RI
RXD
BIT DETECTOR
SAMPLING
START
START