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Serial Boot Facility (SBF)
12-8
Freescale Semiconductor
SBFCR[BLDIV] is not overwritten with the BLDIV[3:0] value read from the SPI memory. Instead, the
SBF uses the SBFCR[BLDIV] value to determine the SPI memory clock.
NOTE
The ability to use the FAST_READ command is limited by the SBF
electrical specifications. Specifically, delays present throughout the system
(including those between the SBF, the pin multiplexing logic, and the actual
I/O pads) effectively limit the maximum frequency at which the SBF
operates and can preclude use of the FAST_READ feature altogether. Even
when the delays within the processor itself are minimized, the actual SPI
memories may have similarly untenable electrical specifications (data input
setup and output valid times).
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 ...