C8051F040-TB Silicon Laboratories Inc, C8051F040-TB Datasheet - Page 298

• Manufacturer Part Number: C8051F040-TB
• Description: BOARD PROTOTYPING W/C8051F040
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F040-TB

• Contents: Board
• Processor To Be Evaluated: C8051F04x
• Interface Type: USB
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: C8051F040
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

C8051F040/1/2/3/4/5/6/7
23.2.2. Capture Mode
In Capture Mode, Timer n will operate as a 16-bit counter/timer with capture facility. When the Timer Exter-
nal Enable bit (found in the TMRnCN register) is set to ‘1’, a high-to-low transition on the TnEX input pin
causes the 16-bit value in the associated timer (TMRnH, TMRnL) to be loaded into the capture registers
(RCAPnH, RCAPnL). If a capture is triggered in the counter/timer, the Timer External Flag (TMRnCN.6)
will be set to ‘1’ and an interrupt will occur if the interrupt is enabled. See
dler” on page 153
As the 16-bit timer register increments and overflows TMRnH:TMRnL, the TFn Timer Overflow/Underflow
Flag (TMRnCN.7) is set to ‘1’ and an interrupt will occur if the interrupt is enabled. The timer can be config-
ured to count down by setting the Decrement Enable Bit (TMRnCF.0) to ‘1’. This will cause the timer to
decrement with every timer clock/count event and underflow when the timer transitions from 0x0000 to
0xFFFF. Just as in overflows, the Overflow/Underflow Flag (TFn) will be set to ‘1’, and an interrupt will
occur if enabled.
Counter/Timer with Capture mode is selected by setting the Capture/Reload Select bit CP/RLn
(TMRnCN.0) and the Timer n Run Control bit TRn (TMRnCN.2) to logic 1. The Timer n respective External
Enable EXENn (TMRnCN.3) must also be set to logic 1 to enable captures. If EXENn is cleared, transi-
tions on TnEX will be ignored.
296
External Clock
SYSCLK
(XTAL1)
Tn
TnE
X
Crossbar
8
2
12
Crossbar
for further information concerning the configuration of interrupt sources.
EXENn
Figure 23.4. Tn Capture Mode Block Diagram
TRn
0
1
TMRnCF
M
T
n
1
M
T
n
0
T
O
G
n
Rev. 1.5
O
T
n
E
TCLK
D
C
E
N
RCAPnL
TMRnL
0xFF
RCAPnH
TMRnH
0xFF
Toggle Logic
Section “12.3. Interrupt Han-
CP/RLn
EXENn
EXFn
C/Tn
TRn
TFn
0
1
Interrupt
(Port Pin)
Tn