c8051t623-g Silicon Laboratories, c8051t623-g Datasheet - Page 219

• Manufacturer Part Number: c8051t623-g
• Description: Full Speed Usb Eprom Mcu Family
• Manufacturer: Silicon Laboratories

C8051T622/3 and C8051T326/7
24.2. PCA0 Interrupt Sources
Figure 24.3 shows a diagram of the PCA interrupt tree. There are five independent event flags that can be
used to generate a PCA0 interrupt. They are: the main PCA counter overflow flag (CF), which is set upon
a 16-bit overflow of the PCA0 counter, an intermediate overflow flag (COVF), which can be set on an over-
flow from the 8th, 9th, 10th, or 11th bit of the PCA0 counter, and the individual flags for each PCA channel
(CCF0, CCF1, and CCF2), which are set according to the operation mode of that module. These event
flags are always set when the trigger condition occurs. Each of these flags can be individually selected to
generate a PCA0 interrupt, using the corresponding interrupt enable flag (ECF for CF, ECOV for COVF,
and ECCFn for each CCFn). PCA0 interrupts must be globally enabled before any individual interrupt
sources are recognized by the processor. PCA0 interrupts are globally enabled by setting the EA bit and
the EPCA0 bit to logic 1.
226
SYSCLK/12
SYSCLK/4
Timer 0 Overflow
ECI
SYSCLK
External Clock/8
C
D
L
I
W
D
E
T
PCA0MD
W
D
C
K
L
C
P
S
2
000
001
010
011
100
101
C
P
S
1
C
P
S
0
C
E
F
Figure 24.2. PCA Counter/Timer Block Diagram
IDLE
C
F
C
R
PCA0CN
C
C
F
2
C
C
F
1
C
C
F
0
Rev. 1.1
0
1
PCA0L
read
Snapshot
Register
PCA0H
PCA0L
To SFR Bus
To PCA Modules
Overflow
CF
To PCA Interrupt System