C515A Datasheet, PDF (30/58 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C515A
Figure 13
Block Diagram of Baud Rate Generation for the Serial Interface
Table 6 below lists the values/formulas for the baud rate calculation of the serial interface with its
dependencies of the control bits BD and SMOD.
Table 6
Serial Interface - Baud Rate Dependencies
Serial Interface 0
Operating Modes
Mode 0 (Shift Register)
Mode 1 (8-bit UART)
Mode 3 (9-bit UART)
Mode 2 (9-bit UART)
Active Control Bits Baud Rate Calculation
BD
SMOD
–
–
f_OSC / 12
0
X
Controlled by timer 1 overflow:
(2^SMOD × timer 1 overflow rate) / 32
1
X
Controlled by baud rate generator
(2^SMOD × f_OSC) /
(64 × baud rate generator overflow rate)
–
0
1
f_OSC / 64
f_OSC / 32
Semiconductor Group
30
1997-10-01