Analog Devices ADSP-21591, Руководство пользователя

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The following figure shows the equivalent circuit to the
Example of Individual FET Switches
figure but utilizes me-
chanical switches that are in the same package. Notice the default is shown by black boxes located closer to the
ON
label of the switches. In order to disconnect these switches, physically move the switch to the OFF position.
Figure 3-3: Example of a Mechanical Switch (Equivalent to Example of Individual FET Switches Figure)
The
Example of Bus Switch
figure 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 sepa-
rated into letter and number, with the number on the lower group (
0B1 ) and the letter on the upper group ( 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.
Software-Controlled Switches (SoftConfig)
3–4
EV-21593-SOM
®
Manual