c8051t602 Silicon Laboratories, c8051t602 Datasheet - Page 143

• Manufacturer Part Number: c8051t602
• Description: Mixed Signal Otp Eprom Mcu Family
• Manufacturer: Silicon Laboratories

17. Programmable Counter Array
The Programmable Counter Array (PCA0) provides enhanced timer functionality while requiring less CPU
intervention than the standard 8051 counter/timers. The PCA consists of a dedicated 16-bit counter/timer
and three 16-bit capture/compare modules. Each capture/compare module has its own associated I/O line
(CEXn) which is routed through the Crossbar to Port I/O when enabled (See
Crossbar Decoder” on page 98
programmable timebase that can select between six sources: system clock, system clock divided by four,
system clock divided by twelve, the external oscillator clock source divided by 8, Timer 0 overflow, or an
external clock signal on the ECI input pin. Each capture/compare module may be configured to operate
independently in one of six modes: Edge-Triggered Capture, Software Timer, High-Speed Output, Fre-
quency Output, 8-Bit PWM, or 16-Bit PWM (each mode is described in
Modules” on page 145
allowing the PCA to be clocked by a precision external oscillator while the internal oscillator drives the sys-
tem clock. The PCA is configured and controlled through the system controller's Special Function Regis-
ters. The basic PCA block diagram is shown in Figure 17.1.
Important Note: The PCA Module 2 may be used as a watchdog timer (WDT), and is enabled in this mode
following a system reset. Access to certain PCA registers is restricted while WDT mode is enabled. See
Section 17.3
for details.
SYSCLK/12
Timer 0 Overflow
SYSCLK
External Clock/8
SYSCLK/4
ECI
). The external oscillator clock option is ideal for real-time clock (RTC) functionality,
Capture/Compare
Figure 17.1. PCA Block Diagram
Module 0
for details on configuring the Crossbar). The counter/timer is driven by a
CLOCK
MUX
PCA
Digital Crossbar
Port I/O
Rev. 0.5
Capture/Compare
16-Bit Counter/Timer
Module 1
C8051T600/1/2/3/4/5
Capture/Compare
Module 2 / WDT
Section “17.2. Capture/Compare
Section “13.1. Priority
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