EFM32G200F64 Energy Micro, EFM32G200F64 Datasheet - Page 276

• Manufacturer Part Number: EFM32G200F64
• Description: MCU 32BIT 64KB FLASH 32-QFN
• Manufacturer: Energy Micro
• Series: Geckor

Specifications of EFM32G200F64

• Core Processor: ARM® Cortex-M3™
• Core Size: 32-Bit
• Speed: 32MHz
• Connectivity: EBI/EMI, I²C, IrDA, SmartCard, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 24
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 3.8 V
• Data Converters: A/D 4x12b, D/A 1x12b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-VQFN Exposed Pad
• Processor Series: EFM32G200
• Core: ARM Cortex-M3
• Data Bus Width: 32 bit
• Data Ram Size: 16 KB
• Interface Type: I2C, UART
• Maximum Clock Frequency: 32 MHz
• Number Of Programmable I/os: 24
• Number Of Timers: 2
• Operating Supply Voltage: 1.8 V to 3.8 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

20 RTC - Real Time Counter
20.1 Introduction
20.2 Features
20.3 Functional Description
2010-09-06 - d0001_Rev1.00
The Real Time Counter (RTC) contains a 24-bit counter and is clocked either by a 32.768 kHz crystal
oscillator, or a 32.768 kHz RC oscillator. In addition to energy modes EM0 and EM1, the RTC is also
available in EM2. This makes it ideal for keeping track of time since the RTC is enabled in EM2 where
most of the device is powered down.
Two compare channels are available in the RTC. These can be used to trigger interrupts and to wake
the device up from a low energy mode. They can also be used with the LETIMER to generate various
output waveforms.
• 24-bit Real Time Counter
• Prescaler
• Two compare registers
The RTC is a 24-bit counter with two compare channels. The RTC is closely coupled with the LETIMER,
and can be configured to trigger it on a compare match on one or both compare channels. An overview
of the RTC module is shown in Figure 20.1 (p. 277) .
• 32.768 kHz/2
• Overflow @ 0.14 hours for prescaler setting = 0
• Overflow @ 4660 hours (194 days) for prescaler setting = 15 (1 s tick)
• A compare match can potentially wake-up the device from low energy modes EM1 and EM2
• Second compare register can be top value for RTC
• Both compare channels can trigger LETIMER
• Compare match events are available to other peripherals through the Peripheral Reflex System
(PRS)
N
, N = 0 - 15
0 1 2 3
0 1 2 3
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276
What?
The Real Time Counter (RTC) ensures
timekeeping in low energy modes. Combined
with the low power 32.768 kHz oscillator
(XTAL or RC), the RTC can run in EM2 with
total current consumption less than 0.9 µA.
Why?
Timekeeping over long time periods is
required in many applications, while using as
little power as possible.
How?
The 32.768 kHz oscillator is used as clock
signal and the RTC has two different
compare registers that can trigger a wake-up.
24-bit resolution and selectable prescaling
allow the system to stay in EM2 for long a
time and still maintain reliable timekeeping.
Quick Facts
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