Inter-Integrated Circuit Peripherals
UG0331 User Guide Revision 15.0
559
15.4.4
Slave0 Address Register
The I
2
C has dual slave address (Slave0/Slave1) decoding capability. The Slave0 address register is a
read/write directly accessible register. The details of this register are provided in the following table.
15.4.5
SMBus Register
The I
2
C SMBus is an optional bus for serial data transfer between the MSS and the FPGA fabric for
Suspend mode. Suspend mode is a Low power mode where most devices are stalled or powered down.
The SMBus register contains specific SMBus related functionality and signals. The details of this register
are provided in the following table.
Table 530 •
Slave0 Address Register (Slave0 ADR)
Bit
Numbe
r
Name
R/W
Reset
Value
Description
7
ADR6
R/W
0
Own Slave0 address bit 6
6
ADR5
R/W
0
Own Slave0 address bit 5
5
ADR4
R/W
0
Own Slave0 address bit 4
4
ADR3
R/W
0
Own Slave0 address bit 3
3
ADR2
R/W
0
Own Slave0 address bit 2
2
ADR1
R/W
0
Own Slave0 address bit 1
1
ADR0
R/W
0
Own Slave0 address bit 0
0
GC
R/W
0
General call (GC) address acknowledge. If the GC bit is set,
the general call address is recognized; otherwise it is ignored.
Table 531 •
SMBus Register (SMBUS)
Bit
Number Name
R/W
Reset
Value Description
7
SMBus reset
R/W 0
Writing one to this bit forces the clock line Low until 35 ms is
exceeded, thus resetting the entire bus as per the SMBus
specification v2.0.
Usage: When the I
2
C is used as a host controller (master),
reset the bus by holding the clock line Low 35 ms. Slaves must
react to this event and reset themselves.
6
SMBSUS_NO control
R/W 0b1
SMBSUS_NO control. SMBUS_NO is a Suspend mode signal
from MSS to fabric.
It is used in Master/Host mode to force other devices into
Power down/Suspend mode. It is active low signal.
SMBSUS_NO and SMBSUS_NI are separate signals (not
wired-AND). If the I
2
C is part of a host-controller, SMBSUS_NO
can be used as an output; if I
2
C is a slave to a host-controller
that is implemented SMBSUS_N, then only SMBSUS_NI's
status is relevant.