ADSP-CM408F Datasheet, PDF (40/87 Pages) Analog Devices – The ADSP-CM408F EZ-KIT Lite is designed

Software-Controlled Switches (SoftConfig)
Figure 2-2 shows two individual FET switches (Pericom PI3A125CEX)
with reference designators UA and UB. Net names ENABLE_A and ENABLE_B
control UA and UB. The default FET switch enable settings in this exam-
ple are controlled by resistors RA and RB which pull the enable pin 1 of UA
and UB to ground (low). In a real example, these enable signals are con-
trolled by the Microchip IO expander. The default pull-down resistors
connects the signals EXAMPLE_SIGNAL_A and EXAMPLE_SIGNAL_B and also
connects signals EXAMPLE_SIGNAL_C and EXAMPLE_SIGNAL_D. To disconnect
EXAMPLE_SIGNAL_A from EXAMPLE_SIGNAL_B, the Microchip IO expander is
used to change ENABLE_A to a logic 1 through software that interfaces with
the Microchip. The same procedure for ENABLE_B would disconnect EXAM-
PLE_SIGNAL_C from EXAMPLE_SIGNAL_D.
Figure 2-2. Example of Individual FET Switches
2-4
ADSP-CM408F EZ-KIT Lite Evaluation System Manual