F990SLIDEREK Silicon Laboratories Inc, F990SLIDEREK Datasheet - Page 3

• Manufacturer Part Number: F990SLIDEREK
• Description: EVAL CAPACITIVE TOUCH SLIDER
• Manufacturer: Silicon Laboratories Inc
• Series: QuickSense™r

Specifications of F990SLIDEREK

• Sensor Type: Touch, Capacitive
• Sensing Range: Slider
• Voltage - Supply: 3V
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: C8051F990
• Processor To Be Evaluated: C8051F990
• Processor Series: C8051F99x
• Data Bus Width: 12 bit
• Operating Supply Voltage: 3 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -
• Sensitivity: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1962

F990-Slider-EK UG
3.5. Wake-on-Slide Firmware Functionality
The F99x slider firmware operates in a low-power state until the user slides a finger across the slider sensor.
Firmware stays in this low-power state while continuously sampling the slider by following the state machine shown
in Figure 2.
Figure 2. State Machine for Wake-on-Slide Functionality
In its first set of states, the slider only samples the pair of pads that the user is required to touch first in order to
begin a slide gesture. When firmware detects a “candidate” touch, the next two pad pairs are sampled at a rate that
is fast enough to detect even a fast swipe. When firmware detects a touch first on the center pads and then on the
final pad pair, it switches to a full-power operational state where the three demos can run.
Note that baselining updates are not shown in the above state machine. In order for the system to reliably detect a
touch event, firmware must maintain a baseline for each pad pair that describes the expected untouched or
“inactive” capacitance of the pad pair.
Figure 3 shows the activity profile for the F99x slider firmware. The X-axis of the drawing is time, and the Y-axis is
current consumed. The system spends most of its time in a low-power sleep mode and only wakes from this low-
power state when firmware detects a wake-on-slide event.
Rev. 0.2
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