C8051F020-TB Silicon Laboratories Inc, C8051F020-TB Datasheet - Page 253

• Manufacturer Part Number: C8051F020-TB
• Description: BOARD PROTOTYPING W/C8051F020
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F020-TB

• Contents: Board
• Processor To Be Evaluated: C8051F02x
• Interface Type: USB
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: C8051F020
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

23.2.1. Edge-triggered Capture Mode
In this mode, a valid transition on the CEXn pin causes PCA0 to capture the value of the PCA0 counter/timer and
load it into the corresponding module's 16-bit capture/compare register (PCA0CPLn and PCA0CPHn). The CAPPn
and CAPNn bits in the PCA0CPMn register are used to select the type of transition that triggers the capture: low-to-
high transition (positive edge), high-to-low transition (negative edge), or either transition (positive or negative edge).
When a capture occurs, the Capture/Compare Flag (CCFn) in PCA0CN is set to logic 1 and an interrupt request is
generated if CCF interrupts are enabled. The CCFn bit is not automatically cleared by hardware when the CPU vec-
tors to the interrupt service routine, and must be cleared by software.
Note: The CEXn input signal must remain high or low for at least 2 system clock cycles in order to be valid.
Port I/O
Crossbar
Figure 23.4. PCA Capture Mode Diagram
CEXn
W
P
M
1
6
n
PCA0CPMn
O
M
E
C
n
C
A
P
P
n
C
A
P
N
n
0
1
M
A
T
n
Rev. 1.4
T
O
G
n
W
M
P
n
E
C
C
F
n
0
1
C
F
C
R
PCA0CN
C
C
F
4
PCA
Timebase
C
C
F
3
C
C
F
2
C
C
C8051F020/1/2/3
F
1
PCA Interrupt
C
C
F
0
Capture
PCA0CPLn
PCA0L
PCA0CPHn
PCA0H
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