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Serial Boot Facility (SBF)
Freescale Semiconductor
12-3
12.3.1
Serial Boot Facility Status Register (SBFSR)
The read-only SBFSR register reflects the amount of boot code loaded through the external SPI memory.
12.3.2
Serial Boot Facility Control Register (SBFCR)
The read-always/write-once SBFCR register controls SBF operation following subsequent warm resets.
Address: 0xFC0A_0018 (SBFSR)
Access: User read-only
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R
BLL
W
Reset
See Note
Note:
Reset value is user-defined (loaded from SPI memory during serial boot following any reset type)
Figure 12-2. Serial Boot Facility Status Register (SBFSR)
Table 12-3. SBFSR Field Descriptions
Field
Description
15–0
BLL
Boot load length. Reflects the number of longwords of boot code loaded from external SPI memory during serial
boot. No boot code was loaded if BLL equals 0x0000. Otherwise, BLL plus 1 longwords were loaded.
Address: 0xFC0A_0020 (SBFCR)
Access: User read/write-once
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
R
0
0
0
0
0
0
0
0
0
0
0
FR
BLDIV
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
See Note
1
Reset value is 0 and is reset only by power-on reset (remains unchanged for other reset types)
Note:
The reset value is loaded from SPI memory during serial boot following power-on reset. It remains unchanged
for other reset types. Prior to this register being loaded from SPI memory, a divisor of 67 is used to begin the
serial boot sequence.
Figure 12-3. Serial Boot Facility Control Register (SBFCR)
Table 12-4. SBFCR Field Descriptions
Field
Description
15–5
Reserved, must be cleared.
4
FR
Fast read. Determines whether the SBF uses the standard
READ
command or flash FAST_READ command on
reboot following any reset other than power-on reset. Because this register is write-once, the application must write
the value for this bit in the same write that the BLDIV field is written. Any subsequent writes to this field prior to a
power-on reset event terminate without effect.
0 SBF uses the standard
READ
command
1 SBF uses the FAST_READ command
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 ...