C8051F040-TB Silicon Laboratories Inc, C8051F040-TB Datasheet - Page 308

• 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
24.2.1. 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 transi-
tion 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 vectors to the interrupt service routine, and
must be cleared by software.
Note: The signal at the CEXn pin must be logic high or low for at least two system clock cycles in order for
it to be recognized as valid by the hardware.
306
Port I/O
Crossbar
Figure 24.4. PCA Capture Mode Diagram
CEXn
W
P
M
1
6
n
PCA0CPMn
O
M
E
C
n
Rev. 1.5
C
A
P
P
n
C
A
P
N
n
0
1
M
A
T
n
T
O
G
n
W
M
P
n
E
C
C
F
n
0
1
C
F
C
R
PCA0CN
C
C
F
5
C
C
F
4
PCA
Timebase
C
C
F
3
C
C
F
2
C
C
F
1
PCA Interrupt
C
C
F
0
Capture
PCA0CPLn
PCA0L
PCA0CPHn
PCA0H