Texas Instruments SLAU039, Руководство пользователя

Страница: 28 / 66

Setting Up the AD50-EVM With the DSK+
3-2
3.1 Setting Up the AD50-EVM With the DSK+
The first step is to couple the two circuit boards together using four inter-board
connectors. See Appendix A for full details. The AD50-EVM takes its power
directly from the DSK+. Inputs and outputs are provided on stereo 3.5 mm
jacks. Note that in single channel mode, the active device connects to the ring
contact on the jack. This is conventionally the left channel on stereo head-
phones. Attaching the AD50-EVM to the DSK+ does not affect the operation
of the AC01 on the DSK+ because the reset default is for both AD50 devices
to be powered down and in slave mode. The master clock source can be the
10.00 MHz oscillator supplied with the DSK+, the 10.24 MHz oscillator pro-
vided with the AD50-EVM or any other oscillator module within the capabilities
of the DSK+ (see section 2.3 for details). It does not matter which socket is
used, so long as only one oscillator module is present in the system. Check
that the operation of the SELFTEST and example programs has not been af-
fected by adding the AD50-EVM or the oscillator selection.
Either type in and assemble a program such as the sine-wave generator listed
below, or modify an appropriate example program such as OSCOPE supplied
with the DSK+. Appendix C shows how OSCOPE was modified to work with
the AD50-EVM.
3.2 Setting Up the AD50-EVM in Stand-Alone Mode
In stand-alone mode the AD50-EVM needs to be connected to a system with
a suitable DSP serial interface. This should include a means of controlling the
RESET signal. The connector marked SERIAL has all the necessary signals,
with interleaved grounds. The POWERDOWN and other control signals are
available on the CONTROL connector. In stand-alone mode all the devices are
powered up by default.
A power supply of 5 V at approximately 150 mA needs to be supplied to the
positive (+) and 0 pins of the PSU connector. The negative (–) pin is an output
from the negative voltage converter.
In stand-alone mode an oscillator of up to 22.579 MHz needs to be inserted
in the socket on the AD50-EVM. A 10.24 MHz oscillator is supplied.
Configuration of the registers in the AD50s is software controlled via the serial
interface, as described for the DSK+ mode. However the RESET, POWER-
DOWN and FC signals need to be set via the CONTROL connector.
3.3 Configuring the Serial Interface
First, the four least significant bits of I/O address 0 must be configured with the
value 2. This selects one AD50 and disables the AC01, holding the AD50 in
reset. Note that the AC01 on the DSK+ is reset by manipulating the XF output
of the C542, whereas the AD50-EVM implements the software reset control
as bit 0 of I/O address 0. This frees the XF bit for other uses, such as driving