MPR121_10 FREESCALE [Freescale Semiconductor, Inc], MPR121_10 Datasheet - Page 48

• Manufacturer Part Number: MPR121_10
• Description: Proximity Capactive touch Senosr controller
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

MPR121
48
BIT TRANSFER
One data bit is transferred during each clock pulse
ACKNOWLEDGE
The acknowledge bit is a clocked 9
each byte transferred effectively requires 9 bits. The master generates the 9
during the acknowledge clock pulse, such that the SDA line is stable low during the high period of the clock pulse. When the
master is transmitting to the MPR121, the MPR121 generates the acknowledge bit, since the MPR121 is the recipient. When the
MPR121 is transmitting to the master, the master generates the acknowledge bit, since the master is the recipient.
THE SLAVE ADDRESS
The MPR121 has a 7-bit long slave address
is low for a write command and high for a read command.
The MPR121 monitors the bus continuously, waiting for a START condition followed by its slave address. When a MPR121
recognizes its slave address, it acknowledges and is then ready for continued communication.
The MPR121 slave addresses are show in
BY TRANSMITTER
BY RECEIVER
SDA
SCL
SDA
SCL
SDA
SDA
SCL
CONDITION
START
CONDITION
MSB
S
START
1
S
th
bit
0
Table 46.
VDD
VSS
SDA
SCL
(Figure
ADDR Pin Connection
Table
(Figure
1
0
51) which the recipient uses to handshake receipt of each byte of data. Thus
46.
Figure 52. Slave Address
Figure 51. Acknowledge
(Figure
Figure 50. Bit Transfer
52). The bit following the 7-bit slave address (bit eight) is the R/W bit, which
1
50). The data on SDA must remain stable while SCL is high.
2
0
I
2
C Address
1
ACKNOWLEDGEMENT
0x4C
0x4D
0x4E
0x4F
th
clock pulse, and the recipient pulls down SDA
CLOCK PULSE FOR
0
8
R/W
CONDITION
ACK
Freescale Semiconductor
STOP
P
9
Sensors