EFM32G200F64 Energy Micro, EFM32G200F64 Datasheet - Page 97

• 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

11.3.3.2 HFRCO, LFRCO and AUXHFRCO
2010-09-06 - d0001_Rev1.00
Figure 11.5. LFXO Pin Connection
It is possible to connect an external clock source to HFXTAL_N/LFXTAL_N pin of the HFXO or LFXO
oscillator. By configuring the HFXOMODE/LFXOMODE fields in CMU_CTRL, the HFXO/LFXO can be
bypassed.
It is possible to calibrate the HFRCO, LFRCO and AUXHFRCO to achieve higher accuracy (see the
device datasheets for details on accuracy). The frequency is adjusted by changing the TUNING fields in
CMU_HFRCOCTL/CMU_LFRCOCTRL/CMU_AUXHFCOCTRL. Changing to a higher value will result
in a higher frequency. Please refer to the datasheet for stepsize details.
The HFRCO can be set to one of several different frequency bands from 1 MHz to 28 MHz by setting the
BAND field in CMU_HFRCOCTRL.The HFRCO frequency bands are calibrated during production test,
and the production tested calibration values can be read from the Device Information (DI) page. The
DI page contains a separate tuning value for each frequency band. During reset HFRCO tuning value
is set the production calibrated value for the 14 MHz band, which is the default frequency band. When
changing to a different HFRCO band, make sure to also update the tuning value.
The LFRCO and AUXHFRCO are also calibrated in production and their TUNING value is set to the
correct value during reset.
The CMU has built-in HW support to efficiently calibrate the RC oscillators at run-time, see Figure 11.6 (p.
97) The concept is to select a reference and compare the RC frequency with the reference frequency.
When the calibration circuit is started, one down-counter (HFCLK counter) running on HFCLK and one
up-counter (CALCLK counter) running on a selectable reference clock are started simultaneously. When
the down-counter has reached 0, both counters are stopped and software can read out the reference
counter value (CALCLK counter) and compare with the start value of the down-counter. Then it is easy
to find the ratio between the reference and the oscillator subject to the calibration. With this HW support,
it is simple to write efficient calibration algorithms in software.
Figure 11.6. HW-support for RC Oscillator Calibration
CMU_CMD.CALSTART
AUXHFRCO
HFRCO
LFRCO
HFXO
LFXO
C
L1
CALCLK
32.768kHz
HFCLK
C
L2
...the world's most energy friendly microcontrollers
(20-bit down-counter)
(20-bit up-counter)
CALCLK Counter
97
CMU_CALCNT
start
LFXTAL_N
LFXTAL_P
stop
EFM32
= 0 ?
Set CMU_IF.CALRDY
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