C8051T630DK Silicon Laboratories Inc, C8051T630DK Datasheet - Page 187

• Manufacturer Part Number: C8051T630DK
• Description: KIT DEV FOR C8051T630 FAMILY
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051T630DK

• Contents: Board, daughter boards, power adapter, cables, documentation and software
• Processor To Be Evaluated: C8051T63x
• Interface Type: USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: C8051T630, T631, T632, T633, T634 and T635 MCUs
• For Use With: 336-1465 - BOARD SOCKET DAUGHTER 20-QFN
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1464

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