Техническая Спецификация для Atmel Evaluation Kit for AT32uC3A0512, 32-Bit AVR Microcontroller Atmel ATEVK1105 ATEVK1105
Модели
ATEVK1105
87
AT32UC3A
14.3
Block Diagram
Figure 14-1.
Real Time Counter module block diagram
14.4
Product Dependencies
14.4.1
Power Management
The RTC is continuously clocked, and remains operating in all sleep modes except Static. Inter-
rupts are not available in DeepStop mode.
14.4.2
Interrupt
The RTC interrupt line is connected to one of the internal sources of the interrupt controller.
Using the RTC interrupt requires the interrupt controller to be programmed first.
14.4.3
Debug Operation
The RTC prescaler is frozen during debug operation, unless the OCD system keeps peripherals
running in debug operation.
14.4.4
Clocks
The RTC can use the internal RC oscillator as clock source. This oscillator is always enabled
whenever these modules are active. Please refer to the Electrical Characteristics chapter for the
characteristic frequency of this oscillator (f
RC
).
The RTC can also use the 32 KHz crystal oscillator as clock source. This oscillator must be
enabled before use. Please refer to the Power Manager chapter for details.
14.5
Functional Description
14.5.1
RTC operation
14.5.1.1
Source clock
The RTC is enabled by writing the EN bit in the CTRL register to 1. The 16-bit prescaler will then
increment on the selected clock. The prescaler cannot be read or written, but it can be reset by
writing the PCLR strobe.
16-bit Prescaler
RC OSC
32-bit counter
RTC_VAL
RTC_TOP
TOPI
IRQ
32 kHz
RTC_CTRL
EN
CLK32
PCLR
1
0
32058K
AVR32-01/12