User guide

Altera Corporation 27
Getting Started EPXA1 Development Kit Getting Started User Guide
1 Additional steps are required to use the SDRAM in boot-from-
serial mode. The information is beyond the scope of this
document, so to use boot-from-serial mode with the
SDRAM, refer to
AN141: Using the SDRAM Controller.
Boot-from-Flash Mode
Setting the BOOT_FLASH external pin to high puts the device in boot-
from-flash mode upon power up. In this mode, the processor accesses the
bootcode from flash memory connected to EBI0, where the bottom 32
Kbytes are mapped from address 0H. The stripe registers are mapped to
their default addresses, based at 7FFFC000H and the remaining
peripherals are not mapped. The BOOT_FLASH pin is permanently tied
high on the EPXA1 development board.
Altera provides a bootcode program with the Excalibur utilities to
facilitate booting from external flash memory. The bootcode performs the
following functions:
1. Initializes the device registers and sets up the memory map
according to the system build descriptor (.sbd) file produced by the
MegaWizard Plug-In.
2. Loads the software into RAM whether it is on- or off-chip memory.
3. Resets the watchdog timer and sets the embedded processor’s
endianness.
4. Loads the PLD configuration data into the device.
5. Passes control to the user’s code.
The hello_flash.hex flash programming file created in “Compile the
Software Application” on page 17 is used to configure the embedded
processor PLD by loading the software and hardware images from an
external flash device. The software image is the hello.hex (Hexadecimal)
file created in “Compile the Software Application” on page 17 and the
hardware image is the hello.sbi created in the “Compile the Hardware
Design” on page 16.