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S E R I A L C O N T R O L M O D U L E : S P I
System boot-over-SPI operation
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437
Available
strapping options
EEPROM/FLASH
header
The boot-over-SPI hardware requires several pieces of user-supplied information to
complete the boot operation. This information must be located in a 128-byte
header starting at address zero in the external memory device. Each entry in the
header is four bytes long.
Header format
This is the format of the 128-byte header.
boot_mode[1:0]
Address width
00
Disabled
01
8-bit address
10
16-bit address
11
24-bit address
Entry
Name
Description
0x0
Size[19:0]
(31:20 reserved)
Total number of words to fetch from the SPI-EEPROM.
The total must include the 32-word header:
(Code image size in bytes + 128) / 4)
0x4
Mode[27:0]
(31:28 reserved)
All SDRAM components contain a Mode register. This
register contains control information required to
successfully access the component. The fields (available
in any SDRAM specification) are defined as follows:
Burst length: 4 for 32-bit data bus, 8 for 16-bit data bus
Burst type: Sequential
CAS latency: Component-specific; 2 or 3
OpMode: Standard
Write burst mode: Programmed burst length
This value must be left-shifted such that it is aligned to the
row address bits as specified in “Address mapping,”
beginning on page 229. For example, 4Mx16 components
can be combined to create a 32-bit bus. These parts require
12 row address bits. With a CAS2 access, the Mode
register contents would be 0x22. This value is shifted 12
places to the left (0x00022000) to form the value in the
SDRAM config field.
0x8
Divisor[9:0]
(31:10 reserved)
Defines the interface data rate for the boot-over-SPI
operation after the initial 16-bytes. A data rate of about
375 Kbps fetches the 16-byte header. See the Clock
Generation register for more details.
0xc
HS Read[0]
(31:1 reserved)
A 1 indicates the external device supports high-speed read
operation. Serial FLASH devices operating above 20MHz
generally support this feature.
0x10
Config register
See the Memory Controller chapter.
Содержание NS9215
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Страница 44: ...P I N O U T 26 5 System clock 44 Hardware Reference NS9215 System clock drawing...
Страница 52: ...P I N O U T 26 5 Power and ground 52 Hardware Reference NS9215...
Страница 80: ...I O C O N T ROL M O D U L E Memory Bus Configuration register 80 Hardware Reference NS9215...
Страница 136: ...WOR KI N G W I TH T H E C P U Noncachable instruction fetches 136 Hardware Reference NS9215...
Страница 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...
Страница 260: ...M E MO R Y C O N T ROL L E R StaticMemory Turn Round Delay 0 3 registers 260 Hardware Reference NS9215...
Страница 354: ...E X T E R N A L D M A DMA Peripheral Chip Select register 354 Hardware Reference NS9215...
Страница 362: ...A E S D AT A E N C R Y P T I O N D E C R Y P T I O N M O D U L E CCM mode 362 Hardware Reference NS9215...
Страница 384: ...I O HU B M OD UL E Module Direct Mode TX Data Last FIFO 384 Hardware Reference NS9215 31 March 2008...
Страница 414: ...S E R I A L C ON T RO L M O D U L E U ART UART Modem Status register 414 Hardware Reference NS9215...
Страница 446: ...S E R I A L C ON T RO L M O D U L E S PI SPI timing characteristics 446 Hardware Reference NS9215...
Страница 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...
Страница 512: ...TI M I NG Clock timing 512 Hardware Reference NS9215...
Страница 514: ...PA CKA GING Processor Dimensions 514 Hardware Reference NS9215 P r o c e s s o r D i m e n s i o n s...
Страница 515: ...PA CKA GING Processor Dimensions www digiembedded com 515...
Страница 516: ...PA CKA GING Processor Dimensions 516 Hardware Reference NS9215...