Datasheet

ADSP-BF609 EZ-KIT Lite Evaluation System Manual 2-5
ADSP-BF609 EZ-KIT Lite Hardware Reference
Figure 2-4 shows a bus switch example, reference designator UC (Pericom
PI3LVD512ZHE), selecting between lettered functionality and numbered
functionality. The signals on the left side are multiplexed signals with
naming convention
letter_number. The right side of the circuit shows the
signals separated into letter and number, with the number on the lower
group (eg. 0B1) and the letter on the upper group (eg. 0B2). The default
setting is controlled by the signal CONTROL_LETTER_NUMBER which is pulled
low. This selects the number signals on the right to be connected to the
multiplexed signals on the left by default. In this example, the Microchip
IO expander is not shown but controls the signal CONTROL_LETTER_NUMBER
and allows the user to change the selection through software.
Figure 2-5 shows the equivalent circuit to Figure 2-4 but utilizes mechan-
ical switches. Notice the default for reference designators SWC and SWD is
illustrated by black boxes located closer to the ON label of the switches to
enable the number signals by default. Also notice the default setting for
reference designators
SWE and SWF is OFF. In order to connect the letters
instead of the numbers, the user physically changes all switches on SWC and
SWD to the OFF position and all switches on SWE and SEF to the ON position.
Figure 2-3. Example of Mechanical Switch Equivalent to Figure 2-2