Specifications

C8051F330/1
22 Rev. 1.1
1.6. Programmable Counter Array
An on-chip Programmable Counter/Timer Array (PCA) is included in addition to the four 16-bit general purpose
counter/timers. The PCA consists of a dedicated 16-bit counter/timer time base with three programmable cap
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ture/compare modules. The PCA clock is derived from one of six sources: the system clock divided by 12, the system
clock divided by 4, Timer 0 overflows, an External Clock Input (ECI), the system clock, or the external oscillator
clock source divided by 8. The external clock source selection is useful for real-time clock functionality, where the
PCA is clocked by an external source while the internal oscillator drives the system clock.
Each capture/compare module can be configured to operate in one of six modes: Edge-Triggered Capture, Software
Timer, High Speed Output, 8- or 16-bit Pulse Width Modulator, or Frequency Output. Additionally, Capture/Compare
Module 2 offers watchdog timer (WDT) capabilities. Following a system reset, Module 2 is configured and enabled
in WDT mode. The PCA Capture/Compare Module I/O and External Clock Input may be routed to Port I/O via the
Digital Crossbar.
Figure 1.8. PCA Block Diagram
Capture/Compare
Module 1
Capture/Compare
Module 0
Capture/Compare
Module 2 / WDT
CEX1
ECI
Crossbar
CEX2 CEX0
Port I/O
16-Bit Counter/Timer
PCA
CLOCK
MUX
SYSCLK/12
SYSCLK/4
Timer 0 Overflow
ECI
SYSCLK
External Clock/8