C8051F302 Silicon Laboratories Inc, C8051F302 Datasheet - Page 124

• Manufacturer Part Number: C8051F302
• Description: IC 8051 MCU 8K FLASH 11MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F30xr

Specifications of C8051F302

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), UART/USART
• Peripherals: POR, PWM, Temp Sensor, WDT
• Number Of I /o: 8
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 8x8b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 11-VQFN
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: I2C, SMBus, UART
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 8
• Number Of Timers: 16 bit
• Operating Supply Voltage: 2.7 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: No

C8051F300/1/2/3/4/5
14.1. 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 14.2), 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
with Auto-Reload” on page
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 14.1.
Where T1
Timer 1 clock frequency is selected as described in
ical 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
Timer 1” on page 133
124
CLK
is the frequency of the clock supplied to Timer 1, and T1H is the high byte of Timer 1 (reload value).
Detected
Start
for more details).
135). The Timer 1 reload value should be set so that overflows will occur at two times
Figure 14.2. UART0 Baud Rate Logic
RX Timer
UartBaudRate
Equation 14.1. UART0 Baud Rate
Timer 1
TH1
TL1
Section “15.2. Timer 2” on page
Overflow
Overflow
Rev. 2.3
=
------------------------------ -
(
256 T1H
T1
–
Section “15.1.3. Mode 2: 8-bit Counter/Timer
CLK
2
2
)
UART0
×
1
-- -
2
RX Clock
TX Clock
141. A quick reference for typ-
Section “15.1. Timer 0 and