EV8000 Datasheet, PDF (14/35 Pages) CML Microcircuits – Evaluation Kit User

Evaluation Kit User Manual for FX828 and FX829
EV8000
1.6 Detailed Description
1.6.1 Hardware Description - Signalling Processor Board
1.6.1.1 Operating Voltage
Jumper JP1 is used to select the operating voltage. Open circuit selects 5.0V operation (default)
and closed circuit (link fitted) selects 3.3V operation.
1.6.1.2 Clock/Oscillator
The evaluation devices may use either an external clock or their own xtal oscillator. A 4.032MHz
xtal is provided on-board for the latter method. The links on jumpers JP2 and JP3, which are
normally fitted, select the xtal oscillator. An external clock may be supplied to JP3 pin 1 once the
links have been removed.
1.6.1.3 Microphone
By fitting a link to jumper JP7, the on-board electret microphone is connected via a buffer amplifier
to the MICIN input of the FX829. The signal applied to the FX829 can be monitored
at TP8. A push-to-talk (PTT) switch is also provided.
1.6.1.4 Loudspeaker
An 8Ω loudspeaker output is provided at the 3.5mm mono jack socket J5. The signal source for
the loudspeaker can be either the FX829 (default) or the FX8x8, link selectable at jumper JP6.
1.6.1.5 C-BUS and optional level shifting.
There are identical connectors (J1 and J2) either side of the board for C-BUS. This enables the
C-BUS source to be connected either side of the signalling processor board and also enables
future C-BUS evaluation boards to be connected in parallel. A third connector (J3) allows the
daisy chaining of a second signalling processor board with alternative /IRQ and /CS lines. This
allows for the emulation of both ends of a radio link, using a single PC.
If it is desired to operate the signalling processor board at V_DD = 3.3V with the interface to C-BUS
operating at V_DD = 5.0V, then level shifting components will need to be added to the signalling
processor board. Level shifting can be added to the C-BUS interface by removing solder links
LK4 to LK7 and fitting the following components:
A 74F07 in position U5.
A pull-up resistor pack in position RP1, suggested value 470Ω.
A pull-up resistor in position R22, suggested value 22kΩ.
A de-coupling capacitor for U5 may be fitted in position C22, suggested value 47nF.
1.6.1.6 Analogue re-configuration
Some discrete components and links around the target devices are socketed to allow path gains
to be adjusted. Also the analogue connector J6 has a second bare footprint, J7, which, in
conjunction with the removable components and links, can be used as a patch board to allow the
user to re-arrange signal paths as required.
1.6.1.7 I_DD Measurement
The current consumption of the FX829 or the FX828 may be measured by removing the link on
jumper JP4 or JP5 respectively and replacing it with a multimeter.
© 2004 CML Microsystems Plc
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UM8000/4