C511 Datasheet, PDF (23/43 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C511 / C513
Serial Interface (USART, not available in the C511/C511A)
The serial port is full duplex and can operate in four modes (one synchronous mode, three
asynchronous modes) as illustrated in table 9. Figure 8 illustrates the block diagram of Baudrate
generation for the serial interface.
Table 9
USART Operating Modes
Mode
0
SCON
SM0 SM1
0
0
1
0
1
2
1
0
3
1
1
Baudrate
Description
f_OSC/12
Timer 1/2 overflow rate
f_OSC/32 or f_OSC/64
Timer 1/2 overflow rate
Serial data enters and exits through R×D.
T×D outputs the shift clock. 8-bit are
transmitted/received (LSB first)
8-bit UART
10 bits are transmitted (through T×D) or
received (R×D)
9-bit UART
11 bits are transmitted (T×D) or
received (R×D)
9-bit UART
Like mode 2 except the variable
baud rate
Figure 8
Block Diagram of Baud Rate Generation for the Serial Interface
Semiconductor Group
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