8 Channel Capacitive Touch Sensor with 8 LED Drivers
Datasheet
Table 3.7 Send Byte Protocol
SLAVE
ADDRESS
REGISTER
ADDRESS
START
WR
ACK
ACK
STOP
1 -> 0
YYYY_YYY
0
0
XXh
0
0 -> 1
3.3.6
SMBus Receive Byte
The Receive Byte protocol is used to read data from a register when the internal register address
pointer is known to be at the right location (e.g. set via Send Byte). This is used for consecutive reads
of the same register as shown in Table 3.8.
Table 3.8 Receive Byte Protocol
SLAVE
START
ADDRESS
RD
ACK
REGISTER DATA
NACK
STOP
1 -> 0
YYYY_YYY
1
0
XXh
1
0 -> 1
3.4
SPI Interface
The SMBus has a predefined packet structure, the SPI does not. The SPI Bus can operate in two
modes of operation, normal 4-wire mode and bi-directional 3-wire mode. All SPI commands consist of
8-bit packets set to a specific slave device (identified by the CS pin).
The SPI bus will latch data on the rising edge of the clock and the clock and data both idle high.
All commands are supported via both operating modes. The supported commands are: Reset Serial
interface, set address pointer, write command and read command. Note that all other codes received
during the command phase are ignored and have no effect on the operation of the device.
tP
tHIGH
tLOW
SPI_CLK
tFALL
tRISE
tSU:DAT
SPI_MSIO or
SPI_MOSI or
SPI_MISO
tD:CLK
tHD:DAT
Figure 3.1 SPI Timing
SMSC CAP1088
Revision 1.1 (08-05-09)
DATA1S9HEET
SMSC [ SMSC CORPORATION ]
