Table of Contents
Advertisement
22.2.2. Software Timer (Compare) Mode
In Software Timer mode, the PCA counter/timer value is compared to the module's 16-bit capture/compare
register (PCA0CPHn and PCA0CPLn). When a match 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. Setting the ECOMn and MATn bits in the PCA0CPMn register enables Software
Timer mode.
Important Note About Capture/Compare Registers : When writing a 16-bit value to the PCA0 Capture/
Compare registers, the low byte should always be written first. Writing to PCA0CPLn clears the ECOMn bit
to '0'; writing to PCA0CPHn sets ECOMn to '1'.
Write to
PCA0CPLn
0
ENB
Reset
Write to
PCA0CPHn
ENB
1
P
W
M
1
6
n
x
Figure 22.5. PCA Software Timer Mode Diagram
C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D
PCA0CPMn
P
E
C
C
M
T
E
W
C
A
A
A
O
C
M
O
P
P
T
G
C
PCA0CPLn
n
M
P
N
n
n
F
n
n
n
n
0 0
0 0
x
Enable
PCA
PCA0L
Timebase
Rev. 1.3
PCA0CPHn
Match
16-bit Comparator
PCA0H
PCA Interrupt
PCA0CN
C
C
C
C
C
C
C
F
R
C
C
C
C
C
F
F
F
F
F
4
3
2
1
0
0
1
259
Advertisement
Table of Contents
Need help?
Do you have a question about the C8051F341 and is the answer not in the manual?
Questions and answers