7.18 Hardware Monitoring Interface
SMSC DS – LPC47M192
Page 129
Rev. 03/30/05
DATASHEET
The Hardware Monitoring Block is a standalone block in the 2. It can be accessed using SMBus interface. This block
is used to monitor +1.5, +1.8, +2.5V, +3.3V, +5V, +12V and Vccp (core processor) voltages. It can also monitor its
own internal HVCC or HVSB. The block can be used to measure internal temperature and two external temperatures
and diode faults. It can indicate out-of-limit temperature and voltage conditions. The block has an ability to output
20ms low pulse.
7.18.1 HARDWARE MONITORING INTERFACE SIGNAL DEFINITION
The following table shows the pins required for the Hardware Monitoring Block.
PIN NAME
TYPE
SDA
Digital I/O
(Open Drain)
output.
SCLK
Digital Input
HVSS
Analog Ground
Internally connected to all of the Hardware Monitoring Block
circuitry.
HVCC
Power
+3.3V VCC pin dedicated to the Hardware Monitoring block.
Can be powered by +3.3V Standby power if monitoring in low
power states is required.
VID0
Digital Input
Voltage supply readout from the processor. This value is read
in the VID Register.
VID1
Digital Input
Voltage supply readout from the processor. This value is read
in the VID Register.
VID2
Digital Input
Voltage supply readout from the processor. This value is read
in the VID Register.
VID3
Digital Input
Voltage supply readout from the processor. This value is read
in the VID Register.
D0-/XNOR_IN
Analog Input/
Digital Input
thermal diode. This serves as the negative input into the A/D.
If held high at power-up, initiates XNOR chain test mode.
D0+
Analog Input
This is the positive input (current source) from the remote
thermal diode. This serves as the positive input into the A/D.
D1-
Analog Input
See D0- pin description.
D1+
Analog Input
See D0+ description.
12V_IN/VID4
Analog
Input/
Digital Input
configured to read the VID4 pin, a voltage supply readout from
the processor. This value is read in the VID4 Register.
+5V_IN
Analog Input
Analog input for +5V
+3.3V_IN
Analog Input
Analog input for +3.3V
+2.5V_IN
Analog Input
Analog input for +2.5V
+1.8V_IN
Analog Input
Analog input for +1.8V
+1.5V_IN
Analog Input
Analog input for +1.5V
+Vccp_IN
Analog Input
Analog input for +Vccp (processor voltage: 0 to 3.0V).
A0/RESET#/
THERM#/XNOR_OUT
(Open Drain)
Can also be configured to be a minimum 20msec low Reset
output pulse, or as an interrupt output for temperature and
voltage interrupts. This pin functions as an output when the
Hardware Monitor Block is in XNOR-Chain test mode.
7.18.2 SMBUS INTERFACE
The host processor communicates with the Hardware Monitor Block through a series of read/write registers via the
SMBus interface. SMBus is a serial communication protocol between a computer host and its peripheral devices.
The SMBus protocol includes a physical layer based on the I
C
serial bus.
DESCRIPTION
System Management Bus bi-directional Data. Open Drain
System Management Bus Clock.
This is the negative input (current sink) from the remote
Defaults to Analog Input for +12V. Optionally, can be
Digital I/O
The lowest order programmable bit of the SMBus Address.