PC4-PRESTO • CompactPCI
®
PlusIO • 4
th
Generation Intel
®
Core™-4xxx Processor
Hardware Monitor LM87
Attached to the SMBus, the PC4-PRESTO is provided with a hardware monitor (LM87). This device is
capable to observe the board and on-board memory temperatures, as well as several supply voltage
rails with a resolution of 8 bit. The following table shows the mapping of the voltage inputs of the
LM87 to the corresponding supply voltages of the PC4-PRESTO:
Input
Source
Resolution
[mV]
Register
AIN1
Processor Core Voltage
9.8
0x28
AIN2
+1.5V
9.8
0x29
VCCP1
+1.35V DDR Voltage
14.1
0x21
VCCP2/D2-
+1.8V
14.1
0x25
+2.5V/D2+
+1.05V
13
0x20
+3.3V
+3.3V
17.2
0x22
+5V
+5V
26
0x23
+12V
+10V
62.5
0x24
Beside the continuous measuring of temperatures and voltages the LM87 may compare these values
against programmable upper and lower boundaries. As soon as a measurement violates the allowed
value range, the LM87 can request an interrupt via the GPI13 input of the QM87 PCH (which may
result in a system management interrupt).
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