Novatel Wireless NRM-EU870D Manual Do Utilizador
43
Novatel Wireless
Revision 1
HW Parameters
The System Management Bus (SMBus) is a two-wire interface through which various system
component chips can communicate with each other and with the rest of the system. It is based on
the principles of operation of I 2 C.
The reader is referred to SMBus reference as described in the System Management Bus
(SMBus) Specification, Version 2.
The System Management Bus (SMBus) is a two-wire interface through which various system
component chips can communicate with each other and with the rest of the system. It is based on
the principles of operation of I 2 C.
The reader is referred to SMBus reference as described in the System Management Bus
(SMBus) Specification, Version 2.
0 for further details on its operation.
The peripheral board communicating to the SMBus must provide pull-ups to 2.6V. It is
recommended that a 2.7 K ohm pull connected to 2.6 Volt rail.
DC parameters
Symbol
recommended that a 2.7 K ohm pull connected to 2.6 Volt rail.
DC parameters
Symbol
Parameter
Limits
Units
Min
Max
VIL
Data, Clock Input Low Voltage
- 0.3
0.86 V
VIH
Data, Clock Input High Voltage
1.78
2.77 V
VOL Data, Clock Output Low Voltage
0
0.45 V
ILEAK Input Leakage
- -
±5
μA
VDD Nominal bus voltage
2.47
2.73
V
Table 2: SMBus DC specification
SM Bus interface Board
Pull up resistors on both lines (SMB_CLK and SMB_DATA) and solid ground connections are
necessary. Without proper pull up values and good ground and instability in communication will
be experienced.
As illustrated below it is recommended that a 2.7 K ohm pull connected to 2.6 Volt rail.
Pull up resistors on both lines (SMB_CLK and SMB_DATA) and solid ground connections are
necessary. Without proper pull up values and good ground and instability in communication will
be experienced.
As illustrated below it is recommended that a 2.7 K ohm pull connected to 2.6 Volt rail.
Figure 9: SM Pull-up Configuration
Host Board
Novatel PCI Express Mini Card
Host Board
Novatel PCI Express Mini Card
GPIO
2.6 V
2.7K
Peripheral
(Slave)
(Slave)
SMB_CLK Pin (32)
EU8X0/E725
SMB_DATA Pin (30)
GPIO
2.6 V
EU8X0/E725
2.7K
Peripheral
(Slave)
(Slave)