Features
120
NS9750 Hardware Reference
8More boot, initialization, or application code is executed.
Example: Boot from flash, SDRAM remapped after boot
The system is set up as:
Chip select 1 is connected to the boot flash device.
Chip select 4 is connected to the SDRAM to be remapped to 0x00000000 after
boot.
The boot sequence is as follows:
1At power-on, the reset chip select 1 is mirrored into chip select 4 (and chip
select 0). The following signals are configured so the nonvolatile memory device
can be accessed:
boot_strap[4:3]
gpio[49]
2When the power-on reset (reset_n) and AHB reset (HRESETn) go inactive, the
processor starts booting from 0x00000000 in memory.
3The software programs the optimum delay values in flash memory so the boot
code can run at full speed.
4The code branches to chip select 1 so the code can continue executing from the
non-remapped memory location.
5The appropriate values are programmed into the memory controller to configure
chip select 4, and the memory device is initialized.
6The address mirroring is disabled by clearing the address mirror (M) field in the
Control register (see page 205).
7The ARM reset and interrupt vectors are copied from flash memory to SDRAM
that can then be accessed at address 0x00000000.
8More boot, initialization, or application code is executed.