C8051T633-GM Silicon Laboratories Inc, C8051T633-GM Datasheet - Page 187

• Manufacturer Part Number: C8051T633-GM
• Description: IC MCU 4KB 20PIN QFN
• Manufacturer: Silicon Laboratories Inc
• Series: C8051T63xr

Specifications of C8051T633-GM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 17
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: OTP
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-QFN
• Processor Series: C8051T6x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 768 B
• Interface Type: UART, SPI, SMBus
• Maximum Clock Frequency: 25 MHz
• Number Of Programmable I/os: 17
• Number Of Timers: 4 x 16-bit
• Operating Supply Voltage: 1.8 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Development Tools By Supplier: C8051T630DK
• Minimum Operating Temperature: - 40 C
• For Use With: 336-1464 - KIT DEV FOR C8051T630 FAMILY
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Details
• Other names: 336-1461-5

24.3.3. Low-Frequency Oscillator (LFO) Capture Mode
The Low-Frequency Oscillator Capture Mode allows the LFO clock to be measured against the system
clock or an external oscillator source. Timer 3 can be clocked from the system clock, the system clock
divided by 12, or the external oscillator divided by 8, depending on the T3ML (CKCON.6), and
T3XCLK[1:0] settings.
Setting TF3CEN to 1 enables the LFO Capture Mode for Timer 3. In this mode, T3SPLIT should be set to
0, as the full 16-bit timer is used. Upon a falling edge of the low-frequency oscillator, the contents of
Timer 3 (TMR3H:TMR3L) are loaded into the Timer 3 reload registers (TMR3RLH:TMR3RLL) and the
TF3H flag is set. By recording the difference between two successive timer capture values, the LFO clock
frequency can be determined with respect to the Timer 3 clock. The Timer 3 clock should be much faster
than the LFO to achieve an accurate reading. This means that the LFO/8 should not be selected as the
timer clock source in this mode.
External Clock / 8
Figure 24.9. Timer 3 Low-Frequency Oscillation Capture Mode Block Diagram
SYSCLK / 12
Low-Frequency
SYSCLK
Oscillator
T3XCLK[1:0]
00
01
M
H
T
3
M
T
3
L
0
1
CKCON
M
T
H
2
T
M
2
L
M
T
1
TF3CEN
M
T
0
S
C
A
1
TR3
S
C
A
0
Rev. 1.0
Capture
TCLK
TMR3RLL TMR3RLH
TMR3L
C8051T630/1/2/3/4/5
TMR3H
T3XCLK1
T3XCLK0
TF3CEN
T3SPLIT
TF3LEN
TF3H
TF3L
TR3
Interrupt
187