UPSD3212A Datasheet, PDF (64/163 Pages) STMicroelectronics – Flash Programmable System Devices with 8032 MCU with USB and Programmable Logic

uPSD3212A, uPSD3212C, uPSD3212CV
Figure 33. Serial Port Mode 3, Block Diagram
Timer1
Overflow
Timer2
Overflow
Write
to
SBUF
÷2
01
SMOD
TCLK
01
Internal Bus
TB8
D SQ
CL
SBUF
Zero Detector
Start
Shift Data
Tx Control
÷16
Tx Clock
TI
Send
RCLK
01
Serial
Port
Interrupt
Sample
1-to-0
Transition
Detector
÷16
Rx Clock
Start
RI
Load SBUF
Rx Control
1FFh
Shift
Rx Detector
Input Shift Register
RxD
Load
SBUF
Shift
Read
SBUF
SBUF
Internal Bus
TxD
AI06846
Figure 34. Serial Port Mode 3, Waveforms
Tx Clock
Write to SBUF
Send
Data
Shift
TxD
TI
Stop Bit
Generator
Rx Clock
RxD
Bit Detector
Sample Times
Shift
RI
S1P1
Start Bit
D0
D1
D2
D3
D4
D5
D6
D7 TB8 Stop Bit
÷16 Reset
Start Bit
D0
D1
D2
D3
D4
D5
D6
D7 RB8 Stop Bit
Transmit
Receive
AI06847
64/163