Bit Flash/Prom Boot (Bmode = 001) - Analog Devices Blackfin ADSP-BF537 Hardware Reference Manual

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Specific Blackfin Boot Modes

Figure 19-14

shows the start of a boot sequence for an 8-bit flash/PROM

*iNITIAL CORE BYTE READ FROM LOCATION

OxO OF THE FLASH TO DETERMINE 8-BIT

FLASH (0X40) OR 16-BIT FLASH (0X60).

**NOTE THAT EACH DATA READ OF AN 8-BIT

FLASH IS IN THE LEAST SIGNIFICANT BYTE

OF THE 16-BIT BUS.

Figure 19-14. Timing Diagram for 8-Bit Flash Boot Sequence

The processor performs an initial core byte read of location 0x0 of

the flash to determine the memory width of the flash. When boot-

ing from a FIFO in this mode, the first byte (which is part of the

first 10-byte header contained within the loader file) must be sent

twice—once for this initial core read and once for the actual boot

16-Bit Flash/PROM Boot (BMODE = 001)

The hardware connection for this boot scenario has already been shown in

19-10. It is one of the advantages of the 16-bit flash boot mode

that it requires the same hardware as the bypass mode. This not only

enables the user to support two booting methods on a given board by a

single jumper on the

cute slow subroutines directly out of the flash/PROM at runtime.

A loader file for a 16-bit flash/PROM will be exactly the same as the one

for the DXE count blocks will be 0xFF80 0060 or 0xFF80 0020 instead of

pin, but it also enables programming to exe-

19-12, except that the ADDRESS of the 10-byte header

ADSP-BF537 Blackfin Processor Hardware Reference