ADVANCED COMMUNICATIONS & SENSING
Rev 0.9 – September 2010
14
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User’s Guide
SX8634/35/44/45 Evaluation Kit
3.1.1 USB Connector (#1)
The USB connector allows the EVK to be connected to a PC from which it will get its power and
configuration/control commands via the dedicated software.
3.1.2 VREG (#2)
VREG is fixed to the typical operating voltage of 3.3V using the Semtech Sc153 voltage regulator, ensuring correct
I2C communication between the SX863x/4x and the FT2232D.
3.1.3 EEPROM (#3)
FT2232D is associated to an EEPROM which keeps the FTDI chip’s parameters when power is turned off. The
EEPROM is used to customize USB device description.
3.1.4 ON/OFF switch (#4)
The ON/OFF switch turns ON (right position) or OFF (left position) the supply for the SX863x/4x and at the same
time the red power indication LED (#6).
3.1.5 Test Switch (#5)
Only applicable for SX864x:
This switch is for Semtech internal use and needs to be always in the left position.
The EVK will not operate if this switch is in the wrong position.
3.1.6 Power Indication LED (#6)
The read LED indicates if the SX863x/4x are turned ON or OFF, according the position of switch (#4).
3.1.7 FT2232D (#7)
The FT2232D from FTDI will be used as a USB to I2C bridge between the PC and the SX863x/4x; moreover it will
also monitor and control RESETB and INTB signals (similar to what a host would do in a final application).
The USB bridge is supplied directly over the USB cable.
3.1.8 Stand-alone Jumpers (#8)
These six jumpers are connecting the FT2232D bridge to the SX863x/4x.
Their purpose is, as their name suggests, being able to disconnect the SX863x/4x from the rest of the circuitry to
access it externally (with an external host, sharing another I2C bus, etc.).
Figure 11: Jumpers
