CAP1005 datasheet(13/53 Pages) SMSC

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5 and 6 Channel Capacitive Touch Sensor

Datasheet

SMSC CAP1005 / CAP1006

Revision 1.1 (08-05-09)

DATASHEET

Chapter 3 Communications

3.1

Communications

The CAP1006-1 communicates using the SMBus or I2C protocol. The CAP1006-2 communicates using

the 2-wire proprietary BC-Link protocol. The CAP1005 communicates using 4-wire SPI bus.

Regardless of the communications mechanism, the device functionality remains unchanged.

3.1.1

SMBus (I2C) Communications

When configured to communicate via the SMBus, the CAP1006 supports the following protocols: Send

Byte, Receive Byte, Read Byte, and Write Byte. In addition, the device supports I2C formatting for block

read and block write protocols.

See Section 3.2 and Section 3.3 for more information on the SMBus bus and protocols respectively.

3.1.2

SPI Communications

The CAP1005 is configured to communicate via SPI bus, using a 4-wire protocol. It does not support

the 3-wire protocol.

See Section 3.4 and Section 3.5 for more information on the SPI bus and protocols respectively.

3.1.3

BC-Link Communications

When BC-Link communications are used, the CAP1006 supports the read byte protocol and the write

byte protocol.

See Section 3.6 for more information on the BC-Link Bus and protocols respectively.

APPLICATION NOTE: Upon power up, the CAP1006 will not respond to any communications for up to 15ms. After

this time, full functionality is available.

3.2

System Management Bus

The CAP1006 communicates with a host controller, such as an SMSC SIO, through the SMBus. The

SMBus is a two-wire serial communication protocol between a computer host and its peripheral

devices. A detailed timing diagram is shown in Figure 3.1. Stretching of the SMCLK signal is supported;

however, the CAP1006 will not stretch the clock signal.

Figure 3.1 SMBus Timing Diagram

SMDATA

SMCLK

TLOW

TRISE

THIGH

TFALL

TBUF

THD:STA

S - Start Condition

P - Stop Condition

THD:DAT

TSU:DAT

TSU:STA

THD:STA

TSU:STO

CAP1005 Datasheet(PDF) 13 Page - SMSC Corporation

CAP1005 Datasheet(HTML) 13 Page - SMSC Corporation

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