EFM8SB2 Datasheet, PDF (7/49 Pages) Silicon Laboratories – The EFM8SB2 highlighted features are listed below

3.5 Counters/Timers and PWM
EFM8SB2 Data Sheet
System Overview
Real Time Clock (RTC0)
The RTC is an ultra low power, 36 hour 32-bit independent time-keeping Real Time Clock with alarm. The RTC has a dedicated 32 kHz
oscillator. No external resistor or loading capacitors are required, and a missing clock detector features alerts the system if the external
crystal fails. The on-chip loading capacitors are programmable to 16 discrete levels allowing compatibility with a wide range of crystals.
The RTC module includes the following features:
• Up to 36 hours (32-bit) of independent time keeping.
• Support for external 32 kHz crystal or internal self-oscillate mode.
• Internal crystal loading capacitors with 16 levels.
• Operation in the lowest power mode and across the full supported voltage range.
• Alarm and oscillator failure events to wake from the lowest power mode or reset the device.
Programmable Counter Array (PCA0)
The programmable counter array (PCA) provides multiple channels of enhanced timer and PWM functionality while requiring less CPU
intervention than standard counter/timers. The PCA consists of a dedicated 16-bit counter/timer and one 16-bit capture/compare mod-
ule for each channel. The counter/timer is driven by a programmable timebase that has flexible external and internal clocking options.
Each capture/compare module may be configured to operate independently in one of five modes: Edge-Triggered Capture, Software
Timer, High-Speed Output, Frequency Output, or Pulse-Width Modulated (PWM) Output. Each capture/compare module has its own
associated I/O line (CEXn) which is routed through the crossbar to port I/O when enabled.
• 16-bit time base.
• Programmable clock divisor and clock source selection.
• Up to six independently-configurable channels
• 8, 9, 10, 11 and 16-bit PWM modes (edge-aligned operation).
• Frequency output mode.
• Capture on rising, falling or any edge.
• Compare function for arbitrary waveform generation.
• Software timer (internal compare) mode.
• Integrated watchdog timer.
Timers (Timer 0, Timer 1, Timer 2, and Timer 3)
Several counter/timers are included in the device: two are 16-bit counter/timers compatible with those found in the standard 8051, and
the rest are 16-bit auto-reload timers for timing peripherals or for general purpose use. These timers can be used to measure time inter-
vals, count external events and generate periodic interrupt requests. Timer 0 and Timer 1 are nearly identical and have four primary
modes of operation. The other timers offer both 16-bit and split 8-bit timer functionality with auto-reload and capture capabilities.
Timer 0 and Timer 1 include the following features:
• Standard 8051 timers, supporting backwards-compatibility with firmware and hardware.
• Clock sources include SYSCLK, SYSCLK divided by 12, 4, or 48, the External Clock divided by 8, or an external pin.
• 8-bit auto-reload counter/timer mode
• 13-bit counter/timer mode
• 16-bit counter/timer mode
• Dual 8-bit counter/timer mode (Timer 0)
Timer 2 and Timer 3 are 16-bit timers including the following features:
• Clock sources include SYSCLK, SYSCLK divided by 12, or the External Clock divided by 8.
• 16-bit auto-reload timer mode
• Dual 8-bit auto-reload timer mode
• Comparator 0 or RTC0 capture (Timer 2)
• Comparator 1 or EXTCLK/8 capture (Timer 3)
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