C8051F021 Silicon Laboratories Inc, C8051F021 Datasheet - Page 244

• 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: -

C8051F020/1/2/3
22.3.1. Mode 0: 16-bit Counter/Timer with Capture
In this mode, Timer 4 operates as a 16-bit counter/timer with capture facility. A high-to-low transition on the T4EX
input pin causes the following to occur:
Timer 4 can use either SYSCLK, SYSCLK divided by 12, or high-to-low transitions on the T4 input pin as its clock
source when operating in Capture mode. Clearing the C/T4 bit (T4CON.1) selects the system clock as the input for
the timer (divided by one or twelve as specified by the Timer Clock Select bit T4M in CKCON). When C/T4 is set to
logic 1, a high-to-low transition at the T4 input pin increments the counter/timer register. As the 16-bit counter/timer
register increments and overflows from 0xFFFF to 0x0000, the TF4 timer overflow flag (T4CON.7) is set and an
interrupt will occur if the interrupt is enabled.
Counter/Timer with Capture mode is selected by setting the Capture/Reload Select bit CP/RL4 (T4CON.0) and the
Timer 4 Run Control bit TR4 (T4CON.2) to logic 1. The Timer 4 External Enable EXEN4 (T4CON.3) must also be
set to logic 1 to enable a capture. If EXEN4 is cleared, transitions on T4EX will be ignored.
244
SYSCLK
1.
2.
3.
The 16-bit value in Timer 4 (TH4, TL4) is loaded into the capture registers (RCAP4H, RCAP4L).
The Timer 4 External Flag (EXF2) is set to ‘1’.
A Timer 4 interrupt is generated if enabled.
T4EX
T4
12
Crossbar
EXEN4
M
T
4
CKCON
M
0
1
T
2
M
T
1
M
T
0
Figure 22.25. T4 Mode 0 Block Diagram
0
1
TR4
Rev. 1.4
Capture
TCLK
RCAP4L
TL4
RCAP4H
TH4
CP/RL4
EXEN4
TCLK0
RCLK0
EXF4
C/T4
TR4
TF4
Interrupt