EFM32G200F64 Energy Micro, EFM32G200F64 Datasheet - Page 342

• 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

25.3.3 Warm-up Time
25.3.4 Input Selection
25.3.4.1 Input Filtering
2010-09-06 - d0001_Rev1.00
Figure 25.2. ADC Conversion Timing
The ADC needs to be warmed up some time before a conversion can take place. This time period is
called the warm-up time. When enabling the ADC or changing references between samples, the ADC
is automatically warmed up for 1µs and an additional 5 µs if the bandgap is selected as reference.
Normally, the ADC will be warmed up only when samples are requested and is shut off when there are
no more samples waiting. However, if lower latency is needed, configuring the WARMUPMODE field
in ADCn_CTRL allows the ADC and/or reference to stay warm between samples, eliminating the need
for warm-up.
Only the bandgap reference selected for scan mode can be kept warm. If a different bandgap reference
is selected for single mode, the warm-up time still applies.
• NORMAL: ADC and references are shut off when there are no samples waiting
• FASTBG: Bandgap warm-up is eliminated, but with reduced reference accuracy
• KEEPSCANREFWARM: The reference selected for scan mode is kept warm. The ADC will still need
• KEEPADCWARM: The ADC and the reference selected for scan mode is kept warm
The minimum warm-up times are given in µs. The timing is done automatically by the ADC, given that
a proper time base is given in the TIMEBASE bits in ADCn_CTRL. The TIMEBASE must be set to the
number of HFPERCLK which corresponds to at least 1 µs. The TIMEBASE only affects the timing of the
warm-up sequence and not the ADC_CLK.
When entering Energy Modes 2 or 3, the ADC must be stopped and WARMUPMODE in ADCn_CTRL
written to 0.
The ADC is connected to 8 external input pins, which can be selected as 8 different single ended inputs or
4 differential inputs. In addition, 6 single ended internal inputs can be selected. The available selections
are given in the register description for ADCn_SINGLECTRL and ADCn_SCANCTRL.
For offset calibration purposes it is possible to internally short the differential ADC inputs and thereby
measure a 0 V differential. Differential 0 V is selected by writing the DIFF bit to 1 and INPUTSEL to 4 in
ADCn_SINGLECTRL. Calibration is described in detail in Section 25.3.10 (p. 347) .
Note
The selected input signal can be filtered, either through an internal low pass RC filter or an internal
decoupling capacitor. The different filter configurations can be enabled through the LPFMODE bits in
ADCn_CTRL.
Prescaled clock (4x)
to be warmed up before conversion.
HFPERCLK
ADC action
ADCn
When VDD/3 is sampled, the acquisition time should be above a lower limit. The reader is
referred to the datasheet for minimum VDD/3 acquisition time.
SINGLEAT/
SCANAT
Bit 11
Bit 10
Bit 9
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Bit 8
342
Bit 7
6-bit value ready 8-bit value ready
Bit 6
Bit 5
Bit 4
Bit 3
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Bit 2
Bit 1
12-bit value ready
Bit 0