User Guide XB1 COM Express Module
Local SMB Devices
The XB1 COM Express Module contains a few devices that are attached to the System Management Bus (SMBus). These are the clock generation chip, the SPD EEPROMs on the
Address | Description |
0x58 | Hardware Monitor/CPU Temperature Sensor (LM87) |
0xA0 | SPD of SODIMM1 |
0xA2 | SPD of SODIMM2 |
0xAE | General Purpose EEPROM |
0xD2 | Main Clock Generation |
Hardware Monitor LM87
The XB1 COM Express Module is provided with a LM87 hardware monitor attached to the SMB. This device is capable to observe board and CPU temperatures as well as several supply voltages generated on the board 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 XB1 COM Express Module:
Input | Source | Resolution | Register |
|
| [mV] |
|
AIN1 | CPU Core Voltage | 9.8 | 0x28 |
AIN2 | +1.05V | 9.8 | 0x29 |
VCCP1 | +1.5V | 14.1 | 0x21 |
VCCP2/D2- | +1.8V | 14.1 | 0x25 |
+2.5V/D2+ | +2.5V | 13 | 0x20 |
+3.3V | +3.3V | 17.2 | 0x22 |
+5V | +5V | 26 | 0x23 |
+12V | +12V | 62.5 | 0x24 |
Besides 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 may request an interrupt via the GPI[7] of the ICH6.
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