Datasheet

Push Buttons and Switches
2-12 ADSP-21489 EZ-Board Evaluation System Manual
Programmable Flag Push Buttons (SW8–11)
Four momentary push buttons (SW8–11) are provided for general-purpose
user input. The buttons are connected to the GPIO pins of the processor.
The push buttons are active high and, when pressed, send a high (1) to the
processor. Switches SW7 and SW13 disconnect the push buttons from the
responding signals. Refer to “DAI [17–20] Enable Switch (SW7)” on
page 2-11 and “External Port Enable Switch (SW13)” on page 2-12 for
more information.
Reset Push Button (SW12)
The reset push button (SW12) resets the following ICs:
• ADSP-21489 processor (U1)
• AD1939 audio codec (U45)
• Parallel flash memory (U18)
The reset also is linked to the expansion II interface; any daughter card
connected to the expansion interface that requires a reset can use SW12.
The reset push button does not reset the standalone debug agent once the
debug agent is connected to a personal computer (PC). After communica-
tion between the debug agent and PC is initialized, pushing a reset button
does not reset the USB chip on the debug agent. The only way to reset the
USB chip on the debug agent is to power down the EZ-Board.
External Port Enable Switch (SW13)
The external port enable switch (SW13) disconnects the control pins of the
processor from the associated peripherals on the EZ-Board and allows the