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M E M O R Y C O N T R O L L E R
Memory map
www.digiembedded.com
205
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M e m o r y m a p
The memory controller provides hardware support for booting from external
nonvolatile memory. During booting, the nonvolatile memory must be located at
address
0x00000000
in memory. When the system is booted, the SRAM or SDRAM
memory can be remapped to address
0x00000000
by modifying the address map in the
AHB decoder.
Power-on reset
memory map
On power-on reset, memory chip select 1 is mirrored onto memory chip select 0 and
chip select 4. Any transactions to memory chip select 0 or chip select 4 (or chip
select 1), then, access memory chip select 1. Clearing the address mirror bit (M) in
the Control register disables address mirroring, and memory chip select 0, chip
select 4, and memory chip select 1 can be accessed as normal.
Chip select 1
memory
configuration
You can configure the memory width and chip select polarity of static memory chip
select 1 by using selected input signals. This allows you to boot from chip select 1.
These are the bootstrap signals:
gpio_a[0], addr[23]:
Memory width select
gpio_a[2]:
Boot mode
Example: Boot
from flash, SRAM
mapped after boot
The system is set up as:
Chip select 1 is connected to the boot flash device.
Chip select 0 is connected to the SRAM to be remapped to
0x00000000
after boot.
This is the boot sequence:
1
At power-on, the reset chip select 1 is mirrored into chip select 0 (and chip
select 4).
Summary of Contents for NS9215
Page 1: ...NS9215 Hardware Reference 90000847_C Release date 10 April 2008...
Page 3: ......
Page 4: ......
Page 26: ...26 Hardware Reference NS9215...
Page 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Page 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Page 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
Page 136: ...WOR KI N G W I TH T H E C P U Noncachable instruction fetches 136 Hardware Reference NS9215...
Page 202: ...S Y S T E M C O N T RO L M OD U L E RTC Module Control register 202 Hardware Reference NS9215...
Page 354: ...E X T E R N A L D M A DMA Peripheral Chip Select register 354 Hardware Reference NS9215...
Page 472: ...R E A L TI M E C L O C K M O D U L E General Status register 472 Hardware Reference NS9215...
Page 512: ...TI M I NG Clock timing 512 Hardware Reference NS9215...
Page 515: ...PA CKA GING Processor Dimensions www digiembedded com 515...
Page 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...