Cypress PSoC CY8CTMG20 Series, Technical Reference Manual

Page: 120 / 308

120 PSoC CY8CTMG20x and CY8CTST200 TRM, Document No. 001-53603 Rev. *C
I2C Slave
by the external master through a write command and if the
pointer value exceeds 1Fh, a NACK is sent.
The following diagram illustrates the bus communication for a data write, a data pointer write, and a data read operation.
Remember that a data write operation always rewrites the data pointer.
Figure 15-4. Two-Wire Interface Bus Communication
A A A A A A A
6 5 4 3 2 1 0 R
W
S A A
D D D D D D D D
7 6 5 4 3 2 1 0
A
D D D D D D D D
7 6 5 4 3 2 1 0
A
D D D D D D D D
7 6 5 4 3 2 1 0
A P
A A A A A A A
6 5 4 3 2 1 0
S A A P
A A A A A A A
6 5 4 3 2 1 0 R
W
S A A
R R R R R R R R
7 6 5 4 3 2 1 0
A
D D D D D D D D
7 6 5 4 3 2 1 0
A
D D D D D D D D
7 6 5 4 3 2 1 0
A P
D D D D D D D D
7 6 5 4 3 2 1 0
R R R R R R R R
7 6 5 4 3 2 1 0
R R R R R R R R
7 6 5 4 3 2 1 0 R
W
Slave
Addr
Data
Address(n)
Data(n) Data(n+1)
Data(n+x)
Data
Address(n)
Data(n)
Data(n+1)
Data(n+x)
Data(n+2)
Master
Slave
Legend
Slave
Addr
Slave
Addr
ACK
Wr
ite
Write
Wr
ite
St
op
NO
A
C
K
AC
K
Sto
p
AC
K
ACK ACK ACK
AC
K
ACK ACK
AC
K
ACK Sto
p
St
ar
t
St
ar
t
Sta
r
t
Write x Bytes to I2C Slave
Set Slave Data Pointer
Read x Bytes to I2C Slave
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