CAP1088 Datasheet, PDF (19/72 Pages) SMSC Corporation – 8 Channel Capacitive Touch Sensor with 8 LED Drivers

8 Channel Capacitive Touch Sensor with 8 LED Drivers
Datasheet
START
1 -> 0
SLAVE
ADDRESS
YYYY_YYY
Table 3.7 Send Byte Protocol
REGISTER
WR
ACK
ADDRESS
0
0
XXh
ACK
0
STOP
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.
START
1 -> 0
SLAVE
ADDRESS
YYYY_YYY
Table 3.8 Receive Byte Protocol
RD
ACK
REGISTER DATA
NACK
1
0
XXh
1
STOP
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.
SPI_CLK
SPI_MSIO or
SPI_MOSI or
SPI_MISO
t_P
t_LOW
t_RISE
t_D:CLK
t_HIGH
t_FALL
t_HD:DAT
t_SU:DAT
Figure 3.1 SPI Timing
SMSC CAP1088
19
DATASHEET
Revision 1.1 (08-05-09)