Hardware Description

3.19User switches and LEDs

The FPGA provides a switch and LED register that enables you to read the general-purpose pushbutton switch and the user switches (S6) and light the user LEDs (located next to switch S6). See Figure 1-1 on page 1-3 for the location of the switches and LEDs. Figure 3-37 shows the interface.

Note

Switch S6-1 and S6-2 are used to control the Boot Monitor. See Boot Monitor configuration on page 2-7.

Set bits [7:0] in the SYS_LED register at 0x10000008 to illuminate LEDs 7–0. The state of the user switches S6[8:1] is present on bits [7:0] of the SYS_SW register at 0x10000004.

The state of the general-purpose pushbutton S3 can be read from bit 4 of the SYS_MISC register at 0x10000060. Setting bit 3 of SYS_MISC causes a S3 depression to generate a PWRFAIL interrupt. The interrupt can be used to test auto-shutdown code or to awaken the processor from sleep mode. See Miscellaneous System Control Register, SYS_MISC on page 4-36.

Figure 3-37 Switch and LED interface

ARM DUI 0224I

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ARM ARM DUI 0224I manual User switches and LEDs, Switch and LED interface