C8051F970-A-GM Datasheet, PDF (425/454 Pages) Silicon Laboratories – Low Power Capacitive Sensing MCU with up to 32 kB of Flash

C8051F97x
33.3.2. 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. An interrupt request is generated if the CCFn interrupt for that module is 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
PCA0CPMn
PECCMT PE
WC A A A O WC
MO P P T GMC
1 MPN n n n F
6nnn
n
n
x 00 00x
Enable
PCA0CPLn PCA0CPHn
PCA Interrupt
PCA0CN
CC
CCC
FR
CCC
FFF
210
16-bit Comparator
Match
0
1
PCA
Timebase
PCA0L
PCA0H
Figure 33.5. PCA Software Timer Mode Diagram
426
Rev 1.0