Maxim Integrated MAXQ Family - Manual (Page 108)

10.1.4 UART Mode 3
This mode has the same operation as Mode 2, except for the baud-rate source. As shown in Figure 10-4, Mode 3 generates baud rates
through the baud clock generator. The bit shifting and protocol are the same.
10-7
MAXQ Family User’s Guide
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
T1
FLAG =
SCON.1
R1
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.3
D8
STOP
LDSBUF
SHIFT
TI
TXD
SHIFT
RI
RXD
BIT DETECTOR
SAMPLING
START
START
Figure 10-4. UART Mode 3
Maxim Integrated