EV2300 Datasheet, PDF (4/18 Pages) Texas Instruments – EVM INTERFACE BOARD

Interfaces
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2.4 HDQ Interface (HDQ)
This interface allows a host computer to interact with a slave or target device through the two-wire SMBus
or the one-wire HDQ interfaces. The ports are labeled with the corresponding signal names above each
port connector. Connect the signal and a ground reference (GND), and optionally VOUT, to a target
device.
The two-wire interface supports SMBus version 1.1 byte, word, block transactions with and without PEC.
The SMBus limits the capacitance on each line (Data and Clock) to 100 pF. The EV2300 places 8 pF on
each line, so a device may place up to 92 pF total. If the capacitive load approaches or exceeds 100 pF,
SMBus communication may not be reliable.
Pin
Name
Description
1
GND
Ground return/reference for HDQ interface
2
VOUT
Controlled EEPROM power. Supplies 5 VDC to a target EEPROM IC
3
HDQ
HDQ one-wire interface. Pulled up to 3.3-V rail with a 10-kΩ resistor
4
VCC
Supplies 3.3 VDC to a target. Current load should be limited to 30 mA
2.5 I²C/EEPROM Interface (I²C)
This interface allows a host computer to interact with a target E²PROM or other I²C interface device such
as a battery monitor device through a two-wire I²C interface. The interface contains a controlled power pin,
the I²C clock and data lines, and a ground reference.
Pin
Name
Description
1
GND
Ground return. Connected to the SMD and HDQ GND
2
SCL
I²C clock. This line must be pulled up by the target.
3
SDA
I²C data. This line must be pulled up by the target.
4
VOUT
Controlled EEPROM power. Supplies 5 VDC to a target EEPROM IC
4
EV2300 EVM Interface Board
SLUU159C – February 2005 – Revised January 2012
Copyright © 2005–2012, Texas Instruments Incorporated
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