Altera Nios Development Board - Manual (Page 33)

Altera Corporation 1–25
September 2004 Nios Development Board Reference Manual, Stratix Edition
Board Components
Figure 1–18. LED1 – LED4
Configuration & Reset Buttons
The Nios development board uses dedicated switches SW8, SW9 and
SW10 for the following fixed functions:
SW8 – CPU Reset
When SW8 is pressed, a logic-0 is driven onto the Stratix devices'
DEV_CLRn pin (and user I/O AC9). The result of pressing SW8 depends
on how the Stratix device is currently configured.
The pre-loaded Nios II reference design treats SW8 as a CPU-reset pin
(see
Figure 1–19 ). The Nios II reference design will reset and start
executing code from its reset address when SW8 is pressed.
Table 1–8. Configuration Status LED Indicators
LED LED Name Color Description
LED3 Loading Green This LED blinks while the configuration controller is actively transferring
data from flash memory into the Stratix FPGA.
LED4 Error Red If the red Error LED is on, then configuration was NOT transferred from
flash memory into the Stratix device. This can happen if, for example, the
flash memory contains neither a valid User or
Safe configuration.
LED1 User Green This LED turns on when the user configuration is being transferred from
flash memory and stays illuminated when the user configuration data is
successfully loaded into the Stratix device. If the Stratix device was
successfully loaded with the user-configuration from flash memory, LED1
will remain on continuously.
LED2 Safe
Config Amber This LED turns on when the safe-configuration is being transferred from
flash memory and stays illuminated if the safe-configuration was
successfully loaded into the Stratix device.