C8051F2XX Datasheet, PDF (120/146 Pages) Silicon Laboratories – Mixed Signal 8 kB ISP Flash MCU Family

C8051F2xx
If T1M (CKCON.4) is logic 1, then the above equation becomes:
T1_OVERFLOWRATE = (SYSCLK) / (256 – TH1).
If T1M (CKCON.4) is logic 0, then the above equation becomes:
T1_OVERFLOWRATE = (SYSCLK/12) / (256 – TH1).
The Timer 2 overflow rate, when in Baud Rate Generator Mode and using an internal clock source, is
determined solely by the Timer 2 16-bit reload value (RCAP2H:RCAP2L). The Timer 2 clock source is
fixed at SYSCLK/2. The Timer 2 overflow rate can be calculated as follows:
T2_OVERFLOWRATE = (SYSCLK/2) / (65536 – [RCAP2H:RCAP2L]).
Timer 2 can be selected as the baud rate generator for RX and/or TX by setting RCLK (T2CON.5) and/or
TCLK (T2CON.4), respectively. When either RCLK or TCLK is set to logic 1, Timer 2 interrupts are auto-
matically disabled and the timer is forced into Baud Rate Generator Mode with SYSCLK/2 as its clock
source. If a different timebase is required, setting the C/T2 bit (T2CON.1) to logic 1 will allow Timer 2 to be
clocked from the external input pin T2. See the Timers section for complete timer configuration details.
RS-232
RS-232
LEVEL
XLTR
TX
RX ^C8051Fxxx
OR
TX
MCU
RX
TX
C8051Fxxx
RX
Figure 16.5. UART Modes 1, 2, and 3 Interconnect Diagram
120
Rev. 1.6