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ADSP-BF537 Blackfin Processor Hardware Reference
6-41
External Bus Interface Unit
The internal 32-bit non-multiplexed address is multiplexed into:
• Data mask for bytes
• SDRAM column address
• SDRAM row address
• Internal SDRAM bank address
Bit
A[0]
is used for 8-bit wide SDRAMs to generate the data masks. The
next lowest bits are mapped into the column address, next bits are mapped
into the row address, and the final two bits are mapped into the internal
bank address. This mapping is based on the
EBCAW
and
EBSZ
values pro-
grammed into the SDRAM memory bank control register.
The SDC uses no burst mode (
BL
=
1
) for read and write operations. This
requires the SDC to post every read or write address on the bus as for
non-sequential reads or writes, but does not cause any performance degra-
dation. For read commands, there is a latency from the start of the read
command to the availability of data from the SDRAM, equal to the CAS
latency. This latency is always present for any single read transfer. Subse-
quent reads do not have latency.
Whenever a page miss to the same bank occurs, the SDC executes a pre-
charge command followed by a bank activate command before executing
the read or write command. If there is a page hit, the read or write com-
mand can be given immediately without requiring the precharge
command.
Содержание Blackfin ADSP-BF537
Страница 42: ...Contents xlii ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 90: ...Development Tools 1 32 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 138: ...Programming Examples 4 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 340: ...SDC Programming Examples 6 84 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 606: ...Programming Examples 9 94 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 660: ...Programming Examples 10 54 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 720: ...Electrical Specifications 11 60 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 840: ...Programming Examples 13 42 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 876: ...Programming Examples 14 36 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 938: ...Programming Examples 15 62 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 958: ...Programming Examples 17 12 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 986: ...Programming Examples 18 28 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1162: ...G 26 ADSP BF537 Blackfin Processor Hardware Reference ...
Страница 1218: ...Index I 56 ADSP BF537 Blackfin Processor Hardware Reference ...