C8051F311 Silicon Laboratories Inc, C8051F311 Datasheet - Page 203

• Manufacturer Part Number: C8051F311
• Description: IC 8051 MCU 16K FLASH 28MLP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F31xr

Specifications of C8051F311

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SMBus (2-Wire/I²C), SPI, UART/USART
• Peripherals: POR, PWM, Temp Sensor, WDT
• Number Of I /o: 25
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 1.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.6 V
• Data Converters: A/D 17x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

18. 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 five 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 131
a 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
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 PCA block diagram is shown in Figure 18.1
Important Note: The PCA Module 4 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 18.3
for details.
Capture/Compare
205). The external oscillator clock option is ideal for real-time clock (RTC) functionality,
Module 0
SYSCLK/12
Timer 0 Overflow
SYSCLK
External Clock/8
SYSCLK/4
ECI
Figure 18.1. PCA Block Diagram
Capture/Compare
for details on configuring the Crossbar). The counter/timer is driven by
Module 1
CLOCK
MUX
PCA
Crossbar
16-Bit Counter/Timer
Port I/O
Rev. 1.7
Capture/Compare
Module 2
C8051F310/1/2/3/4/5/6/7
Capture/Compare
Section “18.2. Capture/Compare
Module 3
Section “13.1. Priority
Capture/Compare
Module 4 / WDT
203