EVB-EMC1002/EMC1033 User Manual

3.8Direct SMBus Connect Option

It is also possible to connect an external SMBus master to the EMC1002 EVB. A few modifications to the circuit are required:

nCut 3 traces connecting JP4 pins 3-4, 5-6 and 7-8 on the bottom side of the PCB. This will disconnect the USB bridge from the SMBus. The pullup resistors for the SMBus SDA, SCL and Alert/Therm2 signals are also disconnected so external pullups will need to be supplied by the SMBus Master.

n

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Install P1 or JP4 to provide an SMBus connector. See the Jumper Settings and Connection List for details.

Optionally remove zero ohm resistor R31. When removed, the USB to SMBus bridge will not supply +3.3V to the circuitry so power will need to be provided from an external source. If R31 is left installed, power will be supplied from the USB connector when connected to a computer or USB hub.

3.9Test Points

Test points are provided for:

nAlert/Therm2 output, EMC1002/1033 pin 6 n Addr/Therm output, EMC1002/1033 pin 4

nGround

n+3.3V power

n+5V_USB power

3.10LED Indicators

LEDs indicate the status of the following signals:

nAlert/Therm2, EMC1002/1033 pin 6 n Addr/Therm, EMC1002/1033 pin 4

n+3.3V

nUSB Activity - blinking indicates USB traffic

nBridge Activity, when ON indicates the Bridge is functioning

Revision 1.1 (12-14-06)

SMSC EMC1002/EMC1033

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