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Serial Boot Facility (SBF)
12-6
Freescale Semiconductor
12.4.3
Execution Transfer
After boot load is complete or if no boot load is requested (SBFSR[BLL] = 0), the following steps
complete the serial boot process:
1. The acquired configuration data is driven to the appropriate modules.
2. The system is released from reset.
3. The ColdFire processor initiates its normal reset vector fetch at address 0.
4. The actual memory that responds to the reset vector fetch depends on whether serial boot load is
requested:
— If SBFSR[BLL] is cleared, the reset vector fetch is handled by the FlexBus module, and
whatever external memory is mapped at address 0, governed by the user-provided setting of
RCON/CCR[FBCONFIG].
— If SBFSR[BLL] is set, the reset vector and boot code are read from the on-chip SRAM. (The
SBF enables the SRAM and maps it to address 0 via the RAMBAR before control of the
processor is restored to the ColdFire core.) The reset vector (initial stack pointer and program
counter) should point to locations in the on-chip SRAM, so that boot code can initialize the
device and load the application software from the SPI memory or via some other mechanism
(e.g. a hard disk drive connected to the ATAPI controller or a network server responding to a
TFTP client).
12.5
Initialization Information
12.5.1
SPI Memory Initialization
The SBF requires that, prior to device power-up, the SPI memory is loaded with data organized according
to
, depending on the exact device used (256- or 360-pin). See
“Reset Configuration (BOOTMOD[1:0] = 11),”
for the reset configuration (SBF_RCON) data definition.
Table 12-5. SPI Memory Organization (360-pin Devices)
Byte Address
Data Contents
0x0
{0000,BLDIV[3:0]}
0x1
BLL[7:0]
0x2
BLL[15:8]
0x3
RCON[7:0]
0x4
RCON[15:8]
...
...
0x12
RCON[127:120]
0x13
1
CODE_BYTE_0
2
0x14
CODE_BYTE_1
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
Page 843: ...Freescale Semiconductor 1 ...
Page 921: ...Revision History A 6 Freescale Semiconductor ...