c8051t602 Silicon Laboratories, c8051t602 Datasheet - Page 124

• Manufacturer Part Number: c8051t602
• Description: Mixed Signal Otp Eprom Mcu Family
• Manufacturer: Silicon Laboratories

C8051T600/1/2/3/4/5
15.1. Enhanced Baud Rate Generation
The UART0 baud rate is generated by Timer 1 in 8-bit auto-reload mode. The TX clock is generated by
TL1; the RX clock is generated by a copy of TL1 (shown as RX Timer in Figure 15.2), which is not user-
accessible. Both TX and RX Timer overflows are divided by two to generate the TX and RX baud rates.
The RX Timer runs when Timer 1 is enabled, and uses the same reload value (TH1). However, an
RX Timer reload is forced when a START condition is detected on the RX pin. This allows a receive to
begin any time a START is detected, independent of the TX Timer state.
Timer 1 should be configured for Mode 2, 8-bit auto-reload (see
Counter/Timer with Auto-Reload” on page 133
flows will occur at two times the desired UART baud rate frequency. Note that Timer 1 may be clocked by
one of five sources: SYSCLK, SYSCLK / 4, SYSCLK / 12, SYSCLK / 48, or the external oscillator clock / 8.
For any given Timer 1 clock source, the UART0 baud rate is determined by Equation 15.1.
Where T1
value). Timer 1 clock frequency is selected as described in
reference for typical baud rates and system clock frequencies is given in Tables 14.1 through 14.6. Note
that the internal oscillator may still generate the system clock when the external oscillator is driving Timer 1
(see
124
Section “16.1. Timer 0 and Timer 1” on page 131
CLK
is the frequency of the clock supplied to Timer 1, and T1H is the high byte of Timer 1 (reload
Detected
Start
Figure 15.2. UART0 Baud Rate Logic
RX Timer
Equation 15.1. UART0 Baud Rate
UartBaudRate
Timer 1
TH1
TL1
Overflow
Overflow
Rev. 0.5
). The Timer 1 reload value should be set so that over-
=
------------------------------ -
(
256 T1H
for more details).
T1
Section “16.2. Timer 2” on page 139
–
CLK
2
2
)
UART0
×
1
-- -
2
Section “16.1.3. Mode 2: 8-bit
RX Clock
TX Clock
. A quick