EVB-EMC2102 SMSC, EVB-EMC2102 Datasheet - Page 7

• Manufacturer Part Number: EVB-EMC2102
• Description: MCU, MPU & DSP Development Tools Evaluation Board
• Manufacturer: SMSC

Specifications of EVB-EMC2102

• Processor To Be Evaluated: EMC2102
• Interface Type: USB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

EVB-EMC2102 User Manual
3 Hardware Description
3.1
3.2
3.3
3.3.1
3.4
SMSC EMC2102
Introduction
EMC2102
USB to SMBus Bridge
Remote Diodes and Zone Heater
The EVB-EMC2102 provides the means to demonstrate EMC2102 features and to view and modify
registers. A +5V fan with the RPM capability range of 4400 rpm ~ 8000 rpm is provided to demonstrate
the fan control functionality. LEDs indicate status information and test points are included to monitor
system voltages with a user provided voltmeter or oscilloscope.
The EMC2102 is an SMBus fan controller and temperature monitor with 1 internal and 3 external
sensors in an 28-pin, 5x5 QFN package. Communications with the EMC2102 is via the SMBus.
The USB to SMBus bridge is based on an 8051 microcontroller 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
microcontroller 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-EMC2102. A few jumper settings
are all that is required to drive the EMC2102:
•
•
The EVB-EMC2102 has 3 on-board temperature sensing diodes (Q1, Q2 and Q3), which are
MMBT3904 transistors in a diode-connected configuration. Diode Q3 has an associated “zone” heater
to demonstrate the temperature measurement. This “zone” heater is a power resistor thermally bonded
to the temperature sensing diode. When enabled, the power resistor will increase the diode
temperature by over 50°C.
To activate the heater, move the jumpers on JP10 from their storage locations (pins 2-3) to the
“enabled” position (pins 1-2). See
Warning:
The on-board thermal diodes may be disconnected by removing the jumpers on JP5 (remote 1), JP6
The Beta Compensation function is designed for CPU substrate diodes and is not compatible with
diode-connected transistors such as the MMBT3904. For this reason, the EMC2102 default settings
are over-ridden by the ChipMan’s initialization code so that Beta Compensation is disabled on the
evaluation board. When connecting to a CPU’s thermial diode, the Beta Compensation function can
be turned on with different values through the ChipMan software (EMC2102 -> HWM -> 0:
Configuration/Status -> External Diode 1/2 Beta).
(remote 2) or JP8 (remote 3). Disconnecting the on-board thermal diodes permits connection of
external temperature sensing diodes to JP5, JP6, JP7 or JP8. See
schematic for more details.
Simply remove the jumpers on JP13 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.
The heating resistor consumes about 280 mA current from the on-board +5V. If the EVB is connected
with a high current (> 200 mA) fan on P1 and the user wants to active the heater, the external power
supply option (see section 3.6) must be selected to avoid over driving the USB cable. The on-board 5V
fan provided by SMSC consumes less than 200 mA current therefore it is safe to run it with the heating
resistor using one single standard USB cable.
Table 3.3
7
Jumper Settings or the schematic for more details.
Table 3.3
Jumper Settings or the
Revision 1.1 (12-13-06)