Analog Devices ADSP-21369 system manual Flag Pins

System Architecture

Figure 2-3illustrates the EZ-KIT Lite’s connections to the DPI. The DPI pins connect to the SPI flash memory, the SPI interface of the AD1835A codec, a UART, a 20-pin header, and five LEDs.

To use the DPI for a different purpose, disable any signal driving the DPI pins with a switch (see “UART Enable Switch (SW5)” on page 2-11). Any DPI pin connected to an LED can be used without having to disconnect the pin. You can, however, see the respective LED turn ON and OFF when using the signal for other purposes.

All of the DPI signals are available externally via the expansion interface connectors (J3–1), as well as the 0.1” spaced header P3. The pinout of these connectors can be found in “Schematics” on page B-1.

FLAG Pins

The processor has four general-purpose IO flag pins. Table 2-1describes the flag connections.

Table 2-1. IO FLAG Pins

FLAG Pin	EZ-KIT Lite Function
FLAG0	Push button (SW2) input
FLAG1	Push button (SW2) input
FLAG2	SDRAM chip select

FLAG3

LED8

For information on how to disable the push buttons from driving the cor- responding processor flag pin, see “Push Button Enable Switch (SW7)” on page 2-12.

The FLAG signals are available externally via the expansion interface con- nectors (J3–1). The pinout of these connectors can be found in “Schematics” on page B-1.

2-6 ADSP-21369 EZ-KIT Lite Evaluation System Manual