C8051T322-GQR Silicon Labs, C8051T322-GQR Datasheet - Page 240

• Manufacturer Part Number: C8051T322-GQR
• Description: 8-bit Microcontrollers - MCU USB-OTP-16K-LQFP32
• Manufacturer: Silicon Labs

Specifications of C8051T322-GQR

• Rohs: yes
• Core: 8051
• Processor Series: C8051
• Data Bus Width: 8 bit

C8051T620/621/320/321/322/323
28. Timers
Each MCU includes four counter/timers: two are 16-bit counter/timers compatible with those found in the
standard 8051, and two are 16-bit auto-reload timer for use with the SMBus or for general purpose use.
These timers can be used to measure time intervals, count external events and generate periodic interrupt
requests. Timer 0 and Timer 1 are nearly identical and have four primary modes of operation. Timer 2 and
Timer 3 offer 16-bit and split 8-bit timer functionality with auto-reload. Additionally, Timer 3 offers the ability
to be clocked from the external oscillator while the device is in Suspend mode, and can be used as a
wake-up source. This allows for implementation of a very low-power system, including RTC capability.
Timers 0 and 1 may be clocked by one of five sources, determined by the Timer Mode Select bits (T1M –
T0M) and the Clock Scale bits (SCA1 – SCA0). The Clock Scale bits define a pre-scaled clock from which
Timer 0 and/or Timer 1 may be clocked (See SFR Definition 28.1 for pre-scaled clock selection).
Timer 0/1 may then be configured to use this pre-scaled clock signal or the system clock. Timer 2 and
Timer 3 may be clocked by the system clock, the system clock divided by 12, or the external oscillator
clock source divided by 8.
Timer 0 and Timer 1 may also be operated as counters. When functioning as a counter, a counter/timer
register is incremented on each high-to-low transition at the selected input pin (T0 or T1). Events with a fre-
quency of up to one-fourth the system clock frequency can be counted. The input signal need not be peri-
odic, but it should be held at a given level for at least two full system clock cycles to ensure the level is
properly sampled.
240
Two 8-bit counter/timers (Timer 0
Timer 0 and Timer 1 Modes:
8-bit counter/timer with auto-
13-bit counter/timer
16-bit counter/timer
reload
only)
Two 8-bit timers with auto-reload
16-bit timer with auto-reload
Timer 2 Modes:
Rev. 1.1
Two 8-bit timers with auto-reload
16-bit timer with auto-reload
Timer 3 Modes: