CAP1114 datasheet(19/102 Pages) MICROCHIP

19 / 102 page

Multiple Channel Capacitive Touch Sensor and LED Driver

Datasheet

SMSC CAP1114

Revision 1.1 (02-04-11)

DATASHEET

The Host will NACK (not acknowledge) the last data byte to be received from the client by holding the

SMBus data line high after the 8th data bit has been sent. For the Block Read protocol, the Host will

ACK each data byte that it receives except the last data byte.

4.1.5

SMBus Stop Bit

The SMBus Stop bit is defined as a transition of the SMBus Data line from a logic ‘0’ state to a logic

‘1’ state while the SMBus clock line is in a logic ‘1’ state. When the CAP1114 detects an SMBus Stop

bit, and it has been communicating with the SMBus protocol, it will reset its client interface and prepare

to receive further communications.

4.1.6

SMBus Time-out

The CAP1114 includes an SMBus time-out feature. Following a 30ms period of inactivity on the SMBus

where the SMCLK pin is held low, the device will time-out and reset the SMBus interface.

The time-out function defaults to disabled. It can be enabled by setting the TIMEOUT bit in the

Configuration register (see Section 6.14).

4.1.7

SMBus and I2C Compliance

The major difference between SMBus and I2C devices is highlighted here. For complete compliance

information, refer to the SMBus 2.0 specification.

1. Minimum frequency for SMBus communications is 10kHz.

2. The client protocol will reset if the clock is held low longer than 30ms.

3. Except when operating in Deep Sleep, the client protocol will reset if both the clock and the data

line are high for longer than 150us (idle condition).

4. I2C devices do not support the Alert Response Address functionality (which is optional for SMBus).

4.2

SMBus Protocols

The CAP1114 is SMBus 2.0 compatible and supports Send Byte, Read Byte, Block Read, Receive

Byte as valid protocols as shown below. The CAP1114 also supports the I2C block read and block write

protocols.

All of the below protocols use the convention in Table 4.1.

4.2.1

SMBus Write Byte

The Write Byte is used to write one byte of data to a specific register as shown in Table 4.2.

Table 4.1 Protocol Format

DATA SENT

TO DEVICE

DATA SENT TO

THE HOST

Data sent

Table 4.2 Write Byte Protocol

START

CLIENT

ADDRESS

ACK

ADDRESS

ACK

DATA

ACK

STOP

1 ->0

0101_000

XXh

0 -> 1

CAP1114 データシート(PDF) 19 Page - Microchip Technology

CAP1114 データシート(HTML) 19 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

データシートダウンロード