la-isppac-powr1014a Lattice Semiconductor Corp., la-isppac-powr1014a Datasheet - Page 25

• Manufacturer Part Number: la-isppac-powr1014a
• Description: In-system Programmable Power Supply Supervisor, Reset Generator And Sequencing Controller
• Manufacturer: Lattice Semiconductor Corp.

Lattice Semiconductor
To start the transaction, the master device holds the SCL line high while pulling SDA low. Address and data bits are
then transferred on each successive SCL pulse, in three consecutive byte frames of 9 SCL pulses. Address and
data are transferred on the first 8 SCL clocks in each frame, while an acknowledge signal is asserted by the slave
device on the 9th clock in each frame. Both data and addresses are transferred in a most-significant-bit-first format.
The first frame contains the 7-bit device address, with bit 8 held low to indicate a write operation. The second frame
contains the register address to which data will be written, and the final frame contains the actual data to be writ-
ten. Note that the SDA signal is only allowed to change when the SCL is low, as raising SDA when SCL is high sig-
nals the end of the transaction.
Figure 5-16. I
Reading a data byte from the LA-ispPAC-POWR1014A requires two separate bus transactions (Figure 5-17). The
first transaction writes the register address from which a data byte is to be read. Note that since no data is being
written to the device, the transaction is concluded after the second byte frame. The second transaction performs
the actual read. The first frame contains the 7-bit device address with the R/W bit held High. In the second frame
the LA-ispPAC-POWR1014A asserts data out on the bus in response to the SCL signal. Note that the acknowledge
signal in the second frame is asserted by the master device and not the LA-ispPAC-POWR1014A.
Figure 5-17. I
The LA-ispPAC-POWR1014ALA-ispPAC-POWR1014A provides 17 registers that can be accessed through its I
interface. These registers provide the user with the ability to monitor and control the device’s inputs and outputs,
and transfer data to and from the device. Table 5-7 provides a summary of these registers.
SDA
STEP 1: WRITE REGISTER ADDRESS FOR READ OPERATION
STEP 2: READ DATA FROM THAT REGISTER
SCL
SDA
SDA
SCL
SCL
START
2
2
C Write Operation
C Read Operation
START
START
A6
1
A5
2
A4
DEVICE ADDRESS (7 BITS)
3
A6
A6
1
1
A3
4
A5
A5
2
2
A2
5
A4
A4
A1
DEVICE ADDRESS (7 BITS)
DEVICE ADDRESS (7 BITS)
6
3
3
A0
7
A3
A3
4
4
R/W
8
A2
A2
ACK
5
5
9
LA-ispPAC-POWR1014/A Automotive Family Data Sheet
A1
A1
6
6
R7
1
A0
A0
7
7
R6
2
R/W
R/W
REGISTER ADDRESS (8 BITS)
R5
3
8
8
5-25
R4
ACK
ACK
4
9
9
R3
5
R2
6
R7
D7
1
1
R1
7
R0
R6
D6
8
2
2
ACK
9
REGISTER ADDRESS (8 BITS)
R5
D5
3
3
READ DATA (8 BITS)
R4
D7
D4
4
4
1
D6
2
R3
D3
5
5
D5
3
WRITE DATA (8 BITS)
R2
D2
6
6
Note: Shaded Bits Asserted by Slave
D4
4
R1
D3
D1
5
7
7
Note: Shaded Bits Asserted by Slave
D2
6
R0
D0
8
8
OPTIONAL
D1
7
ACK
ACK
9
9
D0
8
ACK
9
STOP
STOP
STOP
2
C