1. PSoC CapSenseTM
Daniel Chao
FAE Manager, Asia Pacific

2. Agenda PSoC Solution (CapSenseTM) How It Works - Relaxation Oscillator
Implementation Examples
PSoC Advantage
Available Demo Boards
FAQ
Call To Action

3. CapSenseTM is the Name to use.
PSoC Capacitive Touch Sense Solution
We are trade marking this.
CapSenseTM is the Name to use.

4. Agenda PSoC Solution (CapSenseTM) How It Works - Relaxation Oscillator
Implementation Examples
PSoC Advantage
Available Demo Boards
FAQ
Call To Action

5. How It Works: Simple Physics
CP is sum of sensor pad capacitance and parasitics.
CP is higher when finger is on the sensor pad.
Parasitic Capacitance is generated by coupling from the sensor pad to traces, ground plane, and any surrounding conductive material. CP CP

6. PSoC Solution: Relaxation Oscillator
30-year-old technology
No Patent Restrictions
No external components required
No IC
No Summing Capacitor
No Resistors
Up to 28 pins for sensing in 21x34
Up to 48 pins for sensing in 24x94

7. How It Works: Using the Relaxation Oscillator
1. Charge Cp with current source.
2. Dump at comp. threshold.
3. Count cycles (n):
When finger present Cp Cp+Cf,
4. Measure n,
5. Calculate Dn.
If Dn > the predefined threshold,
6. Denote presence of finger.
Sensor
Pad

8. How It Works: Detecting Presence
Measure CP by charge time.
Charge time determines PWM clock frequency.
Changes in timer count values represent changes in CP.
Compare CP.
Denote presence of capacitive object (finger, etc.) if Dn (DCP) is greater than threshold.
PWM
Oscillator
Timer
Finger Absent
= 32
Dn = 16
= 48
Finger Present

9. Agenda PSoC Solution (CapSenseTM) How It Works - Relaxation Oscillator
Implementation Examples
PSoC Advantage
Available Demo Boards
FAQ
Call To Action

10. Example: Buttons with PSoC CapSense
How it works
Set up buttons and LEDs attached to PSoC
Scan pins in order
Denote presence or absence of finger
Turn on LED for active button
## = press the space-bar button.
SPI, I2C x/y radius & angle from origin vertical
USB if we use radon
proprietary interface from synpatics – I2C
##Synaptics has a patent on the simple diamond (square) pattern used in their touch pads. We implement an hour-glass pattern here.
##Pins are scanned in an order described in the PSoC. Synaptics has a purely sequential order patented but any order will do for the PSoC solution since we merely output status per pin and each pin is associated with an x- or y-position.
##Values are stored in the PSoC.
##From the values, a centroid is calculated and interpolated to a resolution greater than that of the sensor layout itself.
##Position is output to the host in the form or x- and y-values or as corrected/calibrated count values. This can also be done in intervals to increase the update rate to the host.
Buttons are implemented in much the same way. Instead of an x- or y- position, each pin corresponds to a button. Figures for this are shown in slides 5,6 & 9. The PSoC only scans one button (or x/y pin) at a time in the 21x34. In the 24x94 (Radon) there are two analog MUX buses. Therefore, two buttons can be polled simultaneously. This yields a faster scan rate and better resolution.

11. Example: Slider with PSoC CapSense
How it works
Set up slider & attach to PSoC pins
Scan pins in order
Mark frequency value for each detection
Calculate Centroid (Center of Mass) Location
Output position to host
## = press the space-bar button.
SPI, I2C x/y radius & angle from origin vertical
USB if we use radon
proprietary interface from synpatics – I2C
##Synaptics has a patent on the simple diamond (square) pattern used in their touch pads. We implement an hour-glass pattern here.
##Pins are scanned in an order described in the PSoC. Synaptics has a purely sequential order patented but any order will do for the PSoC solution since we merely output status per pin and each pin is associated with an x- or y-position.
##Values are stored in the PSoC.
##From the values, a centroid is calculated and interpolated to a resolution greater than that of the sensor layout itself.
##Position is output to the host in the form or x- and y-values or as corrected/calibrated count values. This can also be done in intervals to increase the update rate to the host.
Buttons are implemented in much the same way. Instead of an x- or y- position, each pin corresponds to a button. Figures for this are shown in slides 5,6 & 9. The PSoC only scans one button (or x/y pin) at a time in the 21x34. In the 24x94 (Radon) there are two analog MUX buses. Therefore, two buttons can be polled simultaneously. This yields a faster scan rate and better resolution.

12. Example: Touchpad with PSoC CapSense
How it works
Set up X/Y-matrix & attach to PSoC pins
Scan pins in order
Mark frequency value for each detection
Calculate Centroid (Center of Mass) Location
Output position to host
## = press the space-bar button.
SPI, I2C x/y radius & angle from origin vertical
USB if we use radon
proprietary interface from synpatics – I2C
##Synaptics has a patent on the simple diamond (square) pattern used in their touch pads. We implement an hour-glass pattern here.
##Pins are scanned in an order described in the PSoC. Synaptics has a purely sequential order patented but any order will do for the PSoC solution since we merely output status per pin and each pin is associated with an x- or y-position.
##Values are stored in the PSoC.
##From the values, a centroid is calculated and interpolated to a resolution greater than that of the sensor layout itself.
##Position is output to the host in the form or x- and y-values or as corrected/calibrated count values. This can also be done in intervals to increase the update rate to the host.
Buttons are implemented in much the same way. Instead of an x- or y- position, each pin corresponds to a button. Figures for this are shown in slides 5,6 & 9. The PSoC only scans one button (or x/y pin) at a time in the 21x34. In the 24x94 (Radon) there are two analog MUX buses. Therefore, two buttons can be polled simultaneously. This yields a faster scan rate and better resolution.

13. Example: Touchpad Finger size is detected by the
number of sensor elements on
which a touch is detected.
For fingers, many elements are
active.
For pens, few elements are
Treatment of position data is
different based on element
number threshold status

14. Implementing Idle
Poll sample of pins so that if finger is present, pressing must wake up system.
If any presence is detected, enter active mode
If no presence is detected, sleep for 100 ms and repeat.
## Polling of the switches is done in groups to canvas a larger area since it is not important where the finger is, only that it is present.
It is possible to get all of the polling done in 1 ms, this will lower the duty cycle to 1% for sleep operation.
The same technique is used in buttons. Larger arrays are scanned simultaneously. The combinations of buttons can be changes to fit the user interface.

15. Sliding Switches and Touch-Pads
Slider switch is a linear array of independent switches
Touch-Pad is TWO linear arrays of switches, one for rows, the other for columns.

16. Diplexing ( that’s di - plexing, not dip - lexing )
Resolution doubling of slider with no additional connections
Switches 0 to n-1 map to virtual switches n to 2n-1
Mapping order selected so that switch area in one half is scattered in the other half
"Switch finding" algorithm looks for adjacent switch contacts, ignores scatter

17. Interpolation Methods
Local interpolation
Scan array
Find largest adjacent values
Compute centroid

18. Agenda PSoC Solution (CapSenseTM) How It Works - Relaxation Oscillator
Implementation Examples
PSoC Advantage
Available Demo Boards
FAQ
Call To Action

19. Existing Solutions Use hard-coded ASICs
No flexibility to design changes or cycles
Limited number of buttons per IC
Require additional controller IC for data processing
Require external components
Resistors for charge current, caps for measurement
Come only as complete modules
Quick design changes not possible
Require difficult-to-use communication protocols
Touch Sensor, Cirque, and Synaptics use ASICs in their modules. Quantum uses a hard-coded IC in their modules and sell the IC as well.
Touch Sensor can only sense a single button per $0.20 ASIC. Quantum can sense up to 32 but the chips are programmed and expensive. No flexibility.
Touch Sensor and Quantum require an addition controller IC in their modules.
Touch Sensor requires resistor to set sensitivity of the IC. Quantum requires resistors to charge the capacitor and an external capacitor for measurement. Cirque and Synaptics both use external resistors in their modules.
Cirque, Touch Sensor, and Synaptics only sell complete modular solutions for specific products. They are not able to respond to design changes as quickly as PSoC.
Synaptics often requires a very difficult communication protocol. PSoC can communicate via SPI, I2C, or USB.

20. PSoC CapSenseTM
Implement buttons, sliders, track pads or proximity sensors all with the same chip!
Bring the flexible architecture, system integration capabilities, and cost reduction of PSoC to your capacitive sensing application.

21. No external components are required for sensing.
PSoC Solution
Sensor
Pads
PSoC senses all switches and drives all LEDs while communicating switch/LED status to the host.
No external components are required for sensing.
ONE-CHIP SOLUTION!!

22. stand-alone solution or as part or a larger system.
PSoC Advantage
PSoC can function as a
stand-alone solution or as part or a larger system.

23. PSoC Advantage: Resources
Device Family
Available Digital Blocks
Required Digital Blocks
Remaining Digital Blocks
Available Flash Memory
Required Flash Memory
Remaining Flash Memory
24794 4 3 1
16k 2k
14k
21x34 8k 6k

24. PSoC Advantage PSoC can offer definitive advantages for design…
Cost reduction
BOM reduction
Flexibility/programmability of PSoC vs. hard-wired ASIC or hard-coded ROM
Multiple switches
Up to 48 CapSense inputs per PSoC!
Sense through up to 4mm of material
Easy serial communications
Further integration of other board elements
Adaptable to touchpad (x/y or r/q matrix) or linear slider
User configurable w/ PSoC Designer tools

25. PSoC Advantage: Competitors
Quantum – Fixed-function IC
Synaptics
Cirque ASIC - only complete (module) solution
Touch Sensor
PSoC is price-competitive with ALL competitor solutions!
User has ultimate flexibility with configurability of PSoC!

26. Sleep/Idle Power Consumption
Normal Scan
No Scan, Wait for Command/INT
Reduced Scan, Power Saving Mode

27. Competitive Analysis: Quantum
Current output set
internally with DAC
externally with discretes
External resistor required
for each sensor pin
PSoC
Quantum
$X-2.00 $X
No fab  More expensive.
Pre-programmed parts  inflexible to customer design changes.

28. BOM Reduction: vs. Quantum
4-button, 4-LED with communication to host….
Quantum
PSoC
PSoC CapSense requires
21 fewer components!!

29. Competitive Analysis: Touch Sensor
Current output set
internally with DAC
externally with discretes
Single Button per ASIC
PSoC
Touch Sensor
$X-2.00 $X
Only one button per ASIC. (Expensive  20¢ per pin)
Whole solutions  No flexibility for customer design changes, updates, or revisions.

30. Agenda PSoC Solution (CapSenseTM) How It Works - Relaxation Oscillator
Implementation Examples
PSoC Advantage
Available Demo Boards
FAQ
Call To Action

31. Released Demo Board

32. Collateral: Demo Board Features
Board Name
Material
Thickness
Button Number
Interpolation
Part Number
Notes
Slider
ABS
1mm
2 + Slider
Yes
CY3220-FPD
LED display
Front Panel Display
3mm 8 No
CY3220-Slider
LCD
Cellular Phone
TBD
0.5mm
4 + Touchpad CY
Navigation
Button Board
2.5mm 4 CY
This is a quick outline of the Demo Boards. These are specs that we have received from customers. If new lead customers have additional specs that can help us make our demos better, that is good.
Demo boards show PSoC’s versatility in the capacitive touch market and showcase specific qualities of the PSoC solution.

33. Demo Boards Slider Features: CapSense Interpolation Single Buttons
January 11, 2002
Demo Boards
Slider
Features:
CapSense
Interpolation
Single Buttons
LED Driver
1-chip Solution
1mm ABS Plastic + Overlay 8

34. Demo Boards Front Panel Display Features: CapSense LCD Display
January 11, 2002
Demo Boards
Front Panel Display
Features:
CapSense
LCD Display
Pseudo-Radio Control
1-chip Solution
3mm ABS Plastic + Overlay 8

35. Part Demos: Pre-programmed PSoCs
CY (Cell Phone Demo)
Features:
CapSense Buttons and Touchpad
x/y or r/q position reporting
I2C Communication
1-chip Solution
0.5mm Overlay
CY (Button Board)
CapSense Buttons
2.5mm Overlay

36. LCD Monitor FP Control Board
January 11, 2002
LCD Monitor FP Control Board
3 Buttons, 16 LEDs 8

37. Mobile Phone Media Control
January 11, 2002
Mobile Phone Media Control
9 Buttons
Backlighting
Detect CW, CCW Movements
Overall Thickness 0.9mm 8

38. Mobile Phone Media Control

39. PSoC CapSenseTM
Thank You