C501_1 Datasheet, PDF (68/121 Pages) Siemens Semiconductor Group – 8-Bit Single-Chip Microcontroller

On-Chip Peripheral Components
C501
6.3.3.2 Using Timer 2 to Generate Baud Rates
Timer 2 is selected as the baud rate generator by setting TCLK and/or RCLK in T2CON. Note then
the baud rates for transmit and receive can be simultaneously different. Setting RCLK and/or TCLK
puts timer 2 into its baud rate generator mode, as shown in figure 6-18.
Figure 6-18
Timer 2 in Baud Rate Generator Mode
The baud rate generator mode is similar to the auto-reload mode, in that rollover in TH2 causes the
timer 2 registers to be reloaded with the 16-bit value in registers RC2H and RC2L, which are preset
by software.
Now the baud rates in modes 1 and 3 are determined by timer 2’s overflow rate as follows:
Modes 1, 3 baud rate = timer 2 overflow rate/16
Semiconductor Group
6-34