Analog Devices ADSP-21479 EZ-Board, Руководство пользователя

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Push Buttons and Switches
2-12 ADSP-21479 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-21479 processor (
U1
)
• AD1939 audio codec (
U19
)
• Parallel flash memory (
U4
)
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
respective control signals to be used on the expansion II interface. See
Table 2-10 .