C8051F537-IT Silicon Laboratories Inc, C8051F537-IT Datasheet - Page 194

• Manufacturer Part Number: C8051F537-IT
• Description: IC 8051 MCU 2K FLASH 20TSSOP
• Manufacturer: Silicon Laboratories Inc
• Series: C8051F53xr

Specifications of C8051F537-IT

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 16
• Program Memory Size: 2KB (2K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.25 V
• Data Converters: A/D 16x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 20-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Other names: 336-1401

C8051F52x/F52xA/F53x/F53xA
19. Programmable Counter Array (PCA0)
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 Section “13.1. Priority Cross-
bar Decoder” on page 121 for details on configuring the Crossbar). The counter/timer is driven by a pro-
grammable 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 three modes: Edge-Triggered Capture, Software Timer, High-Speed Output, Fre-
quency Output, 8-Bit PWM, or 16-Bit PWM (each mode is described in Section “19.2. Capture/Compare
Modules” on page 196). The PCA is configured and controlled through the system controller's Special
Function Registers. The PCA block diagram is shown in Figure 19.1
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 “19.3. Watchdog Timer Mode” on page 202 for details.
194
SYSCLK/12
Timer 0 Overflow
SYSCLK
External Clock/8
SYSCLK/4
ECI
Figure 19.1. PCA Block Diagram
Capture/Compare
Module 0
CLOCK
MUX
PCA
Crossbar
Rev. 1.3
Port I/O
16-Bit Counter/Timer
Capture/Compare
Module 1
Capture/Compare
Module 2