DS41393A-Page iv

© 2009 Microchip Technology, Inc.

8

BASICS OF RESISTIVE SENSORS ................................................................................................... 25

8.1

TERMINOLOGY ................................................................................................................................................25

8.2

GENERAL .......................................................................................................................................................25

8.3

4-WIRE SENSOR.............................................................................................................................................26

8.4

8-WIRE SENSOR.............................................................................................................................................27

8.5

5-WIRE SENSOR.............................................................................................................................................28

8.6

SUMMARY ......................................................................................................................................................28

9

ELECTRICAL SPECIFICATIONS........................................................................................................ 29

9.1

ABSOLUTE MAXIMUM RATINGS(†).....................................................................................................................29

10

PACKAGING .................................................................................................................................... 30

10.1

20 LEAD SOIC ...............................................................................................................................................30

10.2

20 LEAD SSOP ..............................................................................................................................................31

10.3

20 LEAD QFN (ML) ........................................................................................................................................32

FIGURES

Figure 1: Block Diagram................................................................................................................................ 2

Figure 2 : Pin Diagrams – SOIC / SSOP and QFN Packages..................................................................... 3

Figure 3 : Main Schematic (SOIC, SSOP package pin out) ........................................................................ 4

Figure 4 : 4-wire Touch Sensor Interface..................................................................................................... 5

Figure 5 : 5-wire Touch Sensor Interface..................................................................................................... 6

Figure 6 : 8-wire Touch Sensor Interface..................................................................................................... 7

Figure 7 : I

2C Timing Diagram – Receive Data............................................................................................8

Figure 8 : I

2C Timing Diagram – Transmit Data...........................................................................................8

Figure 9 : I

2C Timing Diagram – Touch Report Protocol .............................................................................9

Figure 10 : I

2C Timing Diagram – Command Protocol.................................................................................9

Figure 11 : SPI Timing Diagram – Bit Timing............................................................................................... 9

Figure 12 : SPI Timing Diagram – Touch Report Protocol ........................................................................10

Figure 13 : SPI Timing Diagram – Command Protocol..............................................................................10

Figure 14: 4-Wire Decoding ........................................................................................................................ 26

Figure 15: 8-Wire Decoding ........................................................................................................................ 27

Figure 16: 5-Wire Decoding ........................................................................................................................ 28

Figure 17 : 20 Lead SOIC Package ........................................................................................................... 30

Figure 18 : 20 Lead SSOP Package.......................................................................................................... 31

Figure 19 : 20 Lead QFN Package ............................................................................................................ 32

TABLES

Table 1: Ordering Part Numbers................................................................................................................... 2

Table 2: Pin Descriptions .............................................................................................................................. 3

Table 3 : Bill of Materials.............................................................................................................................. 4

Table 4 : 4/8-wire vs 5-wire Selection .......................................................................................................... 5

Table 5 : Communication Selection ............................................................................................................. 8

Table 6 : Communication Pins ..................................................................................................................... 8

Table 7 : Touch Coordinate Reporting Protocol......................................................................................... 11

Table 8 : Configuration Registers .............................................................................................................. 12

Table 9 : Command Set Summary............................................................................................................. 18

Table 10 : Sensor Comparison .................................................................................................................. 25