EV9800 Datasheet, PDF (12/25 Pages) CML Microcircuits – Evaluation Kit

Evaluation Kit User Manual for CMX980A
EV9800
1.6 Detailed Description
1.6.1 Hardware Description
All analog inputs and outputs of the CMX980A are brought to smb sockets.
Separate digital and analog supplies are provided. The ground planes are linked by wire link LK1.
If the user wishes to provide a separate external supply for the digital circuitry, he or she should do the
following.
• Remove wire links LK1 and LK2.
• Use socket J2 ( unfitted ) to attach digital supply between 8 and 15 Volts d.c.
• The supply rail can be de-coupled by fitting capacitor C32.
Circuitry is provided to convert to and from the differential I and Q channel signals of the CMX980A
from and to single ended signals. This circuitry may be isolated by removing jumpers JP1 to JP5, JP7,
JP8 and JP9.
A 5 Volt power rail and footprint are provided for use with a TI DSKplus.
For those not fitting a DSKplus the serial interface ports for the CMX980A are brought out to a 20 pin
header, J1. The digital signals may be monitored using testpoints TP8 to TP12, TP21, TP22 and TP23.
Level shifting is provided between the DSKplus or external, J1, inputs and the CMX980A.
An on-board oscillator circuit provides the 9.216MHz for MCLK of the CMX980A.
1.6.2 Adjustments and Controls
The analog and digital operating voltages (AV_DD and DV_DD) are set to 3.3V. These may be altered by
changing the socketed components R22 and R23 for AV_DD and R24 and R33 for DV_DD. To select
5.0Volts set R22 and R33 = 620Ω; R23 and R24 = 100Ω. The formula for calculating the values is as
follows:-
R22 + R23 = R24 + R33 = ^{240 (VDD −1.25)}
1.25
Where 240 is the value of R13 or R28 in ohms and V_DD is the required supply voltage.
1.6.3 Firmware Description
The DSP firmware consists of two sections: a kernel and application software. This structure is based
upon the source code supplied with the Texas Instruments DSP kit.
Operation is only possible via the supplied windows software, ES9800xx.EXE.
When ES9800 is started a kernel program is down-loaded to the DSKplus. Once this has been
completed successfully the main windows panel is opened and an application program is downloaded
to the DSKplus.
In general, main panel functions are executed in the PC using only the kernel DSP functions, allowing
read and write access to the CMX980A.
The application demonstrations are initiated from the DSP kernel but are then executed mainly within
the DSP application code.
The files ES9800xx.exe, EF98Kxx.obj and EF9800xx.obj must all be in the same directory on the
user’s PC.
© 1999 Consumer Microcircuits Limited
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