EFM32TG210F32 Energy Micro, EFM32TG210F32 Datasheet - Page 323

• Manufacturer Part Number: EFM32TG210F32
• Description: MCU 32BIT 32KB FLASH 32-QFN
• Manufacturer: Energy Micro
• Series: Tiny Geckor

Specifications of EFM32TG210F32

• 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: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 4K 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: EFM32
• Core: ARM Cortex-M3
• Data Bus Width: 32 bit
• Data Ram Size: 32 KB
• Interface Type: UART, I2C, SPI
• Maximum Clock Frequency: 32 MHz
• Number Of Programmable I/os: 17
• Number Of Timers: 1
• Operating Supply Voltage: 1.8 V to 3.8 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Processor To Be Evaluated: EFM32TG210
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

21.3.6 Decoder
2010-12-21 - d0034_Rev0.90
Figure 21.5. Scan result and interrupt generation
LESENSE includes the possibility to sample both analog comparators simultaneously, effectively cutting
the time spent on sensor interaction in some applications in half. Setting DUALSAMPLE in CTRL enables
this mode. In dual sample mode, the channels of ACMP0 are paired together with the corresponding
channel on ACMP1, i.e. channel x on ACMP0 and channel x on ACMP1 are sampled simultaneously.
The results from sensor measurements can be fed into the decoder register and/or stored in the result
buffer. In this mode, the samples from the AMCPs are placed in the two LSBs of the result stored in the
result buffer. Results from both ACMPs will be evaluated for interrupt generation.
Many applications require some sort of processing of the sensor readings, for instance in the case of
quadrature decoding. In quadrature decoding, the sensors repeatedly pass through a set of states which
corresponds to the position of the sensors. This sequence, and many other decoding schemes, can be
described as a finite state machine. To support this type of decoding without CPU intervention, LESENSE
includes a highly configurable decoder, capable of decoding input from up to four sensors. The decoder
is implemented as a programmable state machine with up to 16 states. When doing a sensor scan,
the results from the sensors are placed in the decoder input register, SENSORSTATE, if DECODE in
CHx_INTERACT is set. The resulting position after a scan is illustrated in Figure 21.6 (p. 323) , where
the bottom blocks show how the SENSORSTATE register is filled. When the scan sequence is complete,
the decoder evaluates the state of the sensors chosen for decoding, as depicted in Figure 21.6 (p. 323)
.
Figure 21.6. Sensor scan and decode sequence
The decoder is a programmable state machine with support for up to 16 states. The behavior of each
state is individually configured in the STx_TCONFA and STx_TCONFB registers. The registers define
possible transitions from the present state. If the sensor state matches COMP in either STx_TCONFA
or STx_TCONFB, a transition to the state defined in NEXTSTATE will be made. It is also possible to
mask out one or more sensors using the MASK bit field. The state of a masked sensor is interpreted
as don't care.
LESENSE
sam ple
counter
ACMP
SENSORSTATE[ 0]
SENSORSTATE[ 3]
COUNTER > = COMPTHRES
COUNTER < COMPTHRES
START
result
CH0
CH0
-
-
-
result
result
CH0
CH1
CH1
-
-
CHx_EVAL_COMP
LESS
GE
result
result
result
CH0
CH1
CH2
CH2
-
CHx_INTERACT_SAMPLE
result
result
result
result
CH0
CH1
CH2
CH3
Scan period
CH3
COUNTER
ACMP
CHx_EVAL_SCANRESINV
Decode
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323
SENSORSTATE
SCANRES[ x]
START
0
result
result
result
result
CH0
CH1
CH2
CH3
CHx_INTERACT_SETIF
CH0
NEGEDGE
POSEDGE
LEVEL
NONE
result
result
result
result
CH0
CH1
CH2
CH3
CH1
interrupt
Set
flag
result
result
result
result
CH0
CH1
CH2
CH3
CH2
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result
result
result
result
CH0
CH1
CH2
CH3
CH3
Decode