C8051F021 Silicon Laboratories Inc, C8051F021 Datasheet - Page 243

• Manufacturer Part Number: C8051F021
• Description: IC 8051 MCU 64K FLASH 64TQFP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F02xr

Specifications of C8051F021

• 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, Temp Sensor, WDT
• Number Of I /o: 32
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Ram Size: 4.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 8x8b, 8x12b; D/A 2x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TQFP, 64-VQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

22.3. Timer 4
Timer 4 is a 16-bit counter/timer formed by the two 8-bit SFRs: TL4 (low byte) and TH4 (high byte). As with
Timers 0 and 1, Timer 4 can use either the system clock or transitions on an external input pin (T4) as its clock
source. The Counter/Timer Select bit C/T4 bit (T4CON.1) selects the clock source for Timer 4. Clearing C/T4 selects
the system clock as the input for the timer (divided by either one or twelve as specified by the Timer Clock Select bit
T4M in CKCON). When C/T4 is set to 1, high-to-low transitions at the T4 input pin increment the counter/timer reg-
ister. Refer to Section
selecting and configuring external I/O pins for digital peripherals.
Timer 4 offers capabilities not found in Timer 0 and Timer 1. It operates in one of three modes: 16-bit Counter/Timer
with Capture, 16-bit Counter/Timer with Auto-Reload or Baud Rate Generator Mode. Timer 4's operating mode is
selected by setting configuration bits in the Timer 4 Control register (T4CON). Below is a summary of the Timer 4
operating modes and the T4CON bits used to configure the counter/timer. Detailed descriptions of each mode follow.
RCLK1
X
0
0
0
1
1
TCLK1
X
0
0
1
0
1
“17.1. Ports 0 through 3 and the Priority Crossbar
CP/RL4
X
X
X
X
1
0
TR4
1
1
1
1
1
0
Mode
16-bit Counter/Timer with Capture
16-bit Counter/Timer with Auto-Reload
Baud Rate Generator for UART1
Baud Rate Generator for UART1
Baud Rate Generator for UART1
Off
Rev. 1.4
Decoder” on page
C8051F020/1/2/3
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for information on
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