Datasheet

MGC3130
DS40001667C-page 22 Advance Information  2012-2013 Microchip Technology Inc.
Power-down Phases
• Processing Operation: Processing mode is
activated
• Request: Request to enter Deep Sleep mode
• Power-down: Power-down state (all analog
signals are down)
• Deep Sleep: Deep Sleep mode has been entered
Signal References
• LSO: Low-Speed Oscillator clock
• HSO: High-Speed Oscillator clock
•VREF Enable: Voltage Reference enable signal
• HSO Enable: High-Speed Oscillator enable signal
• STEP-UP enable: STEP-UP converter enable
signal
4.3 Transmit Signal Generation
The Tx signal generation block provides a bandwidth
limited square wave signal for the transmit electrode.
Frequency hopping adjusts automatically the Tx carrier
frequency in the range of 44-115 kHz, depending on
the environmental noise conditions. GestIC Library
automatically selects the lowest noise working
frequency in case the sensor signal is compromised.
Frequencies can be enabled/disabled via the GestIC
Library.
4.4 Receive (Rx) Channels
There are five identical Rx channels that can be used
for five respective receive electrodes. Four receive
electrodes are required for Position Tracking and
Gesture Recognition. A fifth electrode can be used for
touch detection and to improve distance measurement.
Each channel has its own analog signal conditioning
stage, followed by a dedicated ADC. For specific
features such as Approach Detection, individual Rx
channels can be activated or deactivated via the
GestIC Library. According to the electrode
characteristics, the channels have to be
parameterized.
The signal conditioning block contains analog filtering
and amplification as shown in Figure 4-11.
FIGURE 4-11: SIGNAL CONDITIONING
BLOCK
For individual electrode characteristics, the Rx
channels can be configured as follows:
• Signal matching: The received signal is sampled
at a sampling rate, equal to twice the Tx
frequency providing a high and low ADC sample.
The signal matching block adjusts the received
signal towards the same value of high and low
ADC samples. The offset can be adjusted
accordingly.
• The matched signal output is amplified using a
programmable gain amplifier to achieve a better
sensitivity.
4.5 Analog-to-Digital Converter (ADC)
As outlined in Section 4.4 “Receive (Rx) Channels”,
each Rx channel features a dedicated ADC. The ADC
trigger source can be selected between the internal
clock and an external sync signal. ADC samples are
synchronous with twice the Tx transmit frequency. The
external sync signal is reserved for dual chip/dual zone
designs.
4.6 Signal Processing Unit (SPU)
The MGC3130 features a Signal Processing Unit
(SPU) to control the hardware blocks and process the
advanced DSP algorithms included in the GestIC
Library. It provides filtered sensor data, continuous
position information and recognized gestures to the
application host. The host combines the information
and controls its application.
4.7 Parameters Storage
The MGC3130 provides an embedded 32 kBytes Flash
memory which is dedicated for the GestIC Library and
storage of the individual configuration parameters.
These parameters have to be set according to the
individual electrode design and application. The
GestIC Library and parameters are loaded into
MGC3130 with the provided software tools or,
alternatively, via GestIC Library messages by the
application host. For more details on the MGC3130
tools, please refer to Section 8.0 “Development
Support”.
Rx gain
VDDA/2
Signal Conditioning Block
Rx Input
Signal
matching
Buffer