EVB-EMC1428 SMSC, EVB-EMC1428 Datasheet - Page 7

• Manufacturer Part Number: EVB-EMC1428
• Description: MCU, MPU & DSP Development Tools Eval Brd EMC1428
• Manufacturer: SMSC

Specifications of EVB-EMC1428

• Processor To Be Evaluated: EMC1428
• Interface Type: USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

EMC1428 EVB User Manual
SMSC EMC1428
3 Hardware Description
3.1
3.2
3.2.1
3.3
3.4
3.5
3.6
Introduction
USB to SMBus Bridge
Connecting to Remote Diodes
Resistance Error Correction (REC)
Power Source
Test Points
The EVB-EMC1428 provides the means to demonstrate all of the EMC1428 features and to view and
modify registers. LEDs indicate status information and test points are included to monitor system
voltages with a user provided voltmeter or oscilloscope.
The USB to SMBus bridge is based on an 8051 micro controller with integrated USB and SMBus
interfaces as well as internal flash and RAM. During EVB manufacture, firmware is loaded into the
bridge that provides the interface between the USB and the SMBus. Power is sourced to the micro
controller from the USB interface for device power and communication.
Direct SMBus Connect Option
It is also possible to connect an external SMBus master to the EVB-EMC1428. A few jumper settings
are all that is required to drive the EMC1428 on the EVB:
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This EVB is populated with jumpers to connect to an external diode or CPU/GPU. If connecting to a
CPU’s thermal diode, it is necessary to provide a common ground. Also, it is usually necessary to bias
the appropriate CPU Vcc plane above this common ground to avoid forward-biasing the ESD diodes
with the temperature sensor signals. These connections have been provided on P1. Consult the CPU
manufacturer’s datasheet for guidance on interfacing to the thermal diode. Refer to the schematic EVB-
EMC1428-SCH-7122-RevA.pdf for details on the EVB header connections.
External diode 1 on board the EVB-EMC1428 has a series resistance adjustment on the DN line.
Checking the REC (Resistance Error Correction) feature is accomplished by turning the resistor wheel
R1. With REC off, a significant temperature error will result. When the REC bit is set, the error will be
corrected for.
This EVB requires only one USB connection to power the entire board. The USB-SMBus bridge
regulates the +5V USB power to +3.3V used by the EMC1428 and other EVB circuitry.
Test points are provided for:
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Simply remove the jumpers on JP19 and connect the SMBus master to the SCL, SDA and ALERT
pins, as well as an external supply for +3.3V.
The +3.3V can be supplied by the SMBus bridge by leaving the +3.3V jumper in place and retaining
the USB connection.
Ground
VDD supply pin
+3.3V power
+5V_USB power
ALERT and SYS_SHDN outputs
7
Revision 1.0 (08-21-07)