EFM32G200F64 Energy Micro, EFM32G200F64 Datasheet - Page 291

• 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

21.3.3.3 Clock Source
21.3.3.4 RTC Trigger
2010-09-06 - d0001_Rev1.00
Figure 21.5. LETIMER Double Repeat State Machine
The LETIMER clock source and its prescaler value are defined in the Clock Management Unit (CMU).
The LFACLK
LETIMER Clock Frequency
where the exponent LETIMERn is a 4 bit value in the CMU_LFAPRESC0 register.
To use this module, the LE interface clock must be enabled in CMU_HFCORECLKEN0, in addition to
the module clock.
The LETIMER can be configured to start on compare match events from the Real Time Counter (RTC).
If RTCC0TEN in LETIMERn_CTRL is set, the LETIMER will start on a compare match on RTC compare
channel 0. In the same way, RTCC1TEN in LETIMERn_CTRL enables the LETIMER to start on a
compare match with RTC compare channel 1.
Note
CNT = CNT - 1
CNT = TOP*
The LETIMER can only use compare match events from the RTC if the LETIMER runs
at a higher than or equal frequency than the RTC. Also, if the LETIMER runs at twice the
frequency of the RTC, a compare match event in the RTC will trigger the LETIMER twice.
Four times the frequency gives four consecutive triggers, etc. The LETIMER will only
continue running if triggered while it is running, so the multiple-triggering will only have an
effect if you try to disable the RTC when it is being triggered.
LETIMERn
has a frequency given by Equation 21.1 (p. 291) .
NO
NO
NO
f
LFACKL_LETIMERn
REP0 = = 0
REP1 = = 0
CNT = = 0
START
YES
YES
YES
and
NO
= 32.768/2
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291
RUNNING
CNT = = 0
REP0 < 2
REP1 < 2
YES
YES
YES
And
LETIMERn
Wait for positive clock edge
NO
If (COMP0TOP)
Else
TOP*
NO
TOP* = COMP0
TOP* = 0xFFFF
CNT = CNT - 1
CNT = TOP*
If (REP0 > 0)
If (REP1 > 0)
STOP = 1
REP0 = 0
REP0 = REP0 - 1
REP1 = REP1 - 1
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If (STOP)
Else if (START)
End if
START = 0
STOP = 0
RUNNING = 0
RUNNING = 1
(21.1)