Specific Blackfin Boot Modes
19-36
ADSP-BF537 Blackfin Processor Hardware Reference
8-Bit Flash/PROM Boot (BMODE = 001)
Booting from 8-bit flash requires the same
BMODE
settings as with 16-bit
flash. The two modes are differentiated by the first byte read in. While
booting from 8-bit flash/PROM sounds cheaper and may result in smaller
board space, there are also some disadvantages compared to the 16-bit
mode: 8-bit mode supports only up to 512k byte devices directly, whereas
16-bit mode supports up to 1M byte. Because code execution from 8-bit
external memory is not supported, in 8-bit mode the usage of the
flash/PROM device is most likely restricted to booting purposes. The boot
kernel assumes these conditions for the flash boot mode (
BMODE
=
001
):
• Asynchronous Memory Bank (AMB) 0 enabled
• 16-bit packing for AMB 0 enabled
• Bank 0
RDY
is set to active high
• Bank 0 hold time (read/write deasserted to
AOE
deasserted) =
3 cycles
• Bank 0 read/write access times = 15 cycles
Since the EBIU on the Blackfin processor is 16 bits wide (hence no
ADDR[0]
), an 8-bit flash/PROM occupies only the lower 8 bits of the data
bus (
D[7:0]
).
illustrates the pin-to-pin connections between
the Blackfin processor and an 8-bit flash/PROM.
Summary of Contents for Blackfin ADSP-BF537
Page 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Page 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Page 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...