C504 SIEMENS [Siemens Semiconductor Group], C504 Datasheet - Page 24

• Manufacturer Part Number: C504
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Serial Interface (USART)
The serial port is full duplex and can operate in four modes (one synchronous mode, three
asynchronous modes) as illustrated in table 6. The possible baudrates can be calculated using the
formulas given in table 6.
Table 6
USART Operating Modes
Mode
0
1
2
3
Figure 8
Block Diagram of Baud Rate Generation for the Serial Interface
Semiconductor Group
SM0
0
0
1
1
SCON
SM1
0
1
0
1
Timer 1/2 overflow rate
Timer 1/2 overflow rate
f
OSC
Baudrate
/32 or
f
OSC
/12
f
OSC
/64
24
Description
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
C504