Altera Nios Development Board - Manual (Page 38)

2–30 Altera Corporation
Nios Development Board Reference Manual, Stratix II Edition July 2005
Factory & User Configurations
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 II I/O pin AA15
(DEV_CLRn). The result of pressing SW8 depends on how the Stratix II
device is currently configured.
The factory-programmed Nios II reference design treats SW8 as a CPU-
reset pin (see
Figure 2–16 ). The Nios II reference design will reset and
start executing code from its reset address when SW8 is pressed.
Figure 2–16. CPU Reset Button
SW9 – Factory Config
Pressing Factory Config (SW9) commands the configuration controller to
re-configure the Stratix II device with the factory configuration.
SW10 – Reset, Config
Reset, Config (SW10) is the power-on reset button (see Figure 2–17 ).
When SW10 is pressed, a logic 0 is driven to the power-on reset controller
(U18). See
“Power-Supply Circuitry” on page 2–35 for more details. After
SW10 is pressed, the configuration controller will load the Stratix II
device from flash memory.