C8051F066-GQ Silicon Laboratories Inc, C8051F066-GQ Datasheet - Page 278

• Manufacturer Part Number: C8051F066-GQ
• Description: MCU 8-Bit C8051F06x 8051 CISC 32KB Flash 3.3V 100-Pin TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F06xr

Specifications of C8051F066-GQ

• Package: 100TQFP
• Device Core: 8051
• Family Name: C8051F06x
• Maximum Speed: 25 MHz
• Operating Supply Voltage: 3.3 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 59
• Interface Type: I2C/SMBus/SPI/UART
• On-chip Adc: 2-chx16-bit
• Number Of Timers: 5
• Ram Size: 4.25 KB
• Program Memory Size: 32 KB
• Program Memory Type: Flash
• Operating Temperature: -40 to 85 °C
• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: EBI/EMI, SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 59
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 2x16b
• Oscillator Type: Internal
• Package / Case: 100-TQFP, 100-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 336-1221

C8051F060/1/2/3/4/5/6/7
23.1. Enhanced Baud Rate Generation
The UART1 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 23.2), 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
Timer with Auto-Reload” on page
at two times the desired baud rate. 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 UART1 baud rate is determined by Equation 23.1.
Where T1
value). Timer 1 clock frequency is selected as described in
page
through Table 23.6. Note that the internal oscillator may still generate the system clock when the external
oscillator is driving Timer 1 (see
278
287. A quick reference for typical baud rates and system clock frequencies is given in Table 23.1
CLK
is the frequency of the clock supplied to Timer 1, and T1H is the high byte of Timer 1 (reload
Detected
Start
RX Timer
Section “24.1. Timer 0 and Timer 1” on page 287
UartBaudRate
Figure 23.2. UART1 Baud Rate Logic
289). The Timer 1 reload value should be set so that overflows will occur
Timer 1
TH1
TL1
Equation 23.1. UART1 Baud Rate
Overflow
Overflow
Rev. 1.2
=
------------------------------ -

256 T1H
T1
–
CLK
Section “24.1. Timer 0 and Timer 1” on
2
2
Section “24.1.3. Mode 2: 8-bit Counter/

UART1

1
-- -
2
RX Clock
TX Clock
for more details).