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ADSP-BF537 Blackfin Processor Hardware Reference
6-51
External Bus Interface Unit
Bank Activation Command
The bank activation command is required for first access to any internal
bank in SDRAM. Any subsequent access to the same internal bank but
different row will be preceded by a precharge and activation command to
that bank.
However, if an access to another bank occurs, the SDC leaves the current
page open and issues a bank activate command before executing the read
or write command to that bank. With this method, called multibank oper-
ation, one page per bank can be open at a time, which results in a
maximum of 4 pages.
Read/Write Command
A read/write command is executed if the next read/write access is in the
present active page. During the read command, the SDRAM latches the
column address. The delay between activate and read commands is deter-
mined by the t
RCD
parameter. Data is available from the SDRAM after
the CAS latency has been met.
In the write command, the SDRAM latches the column address. The
write data is also valid in the same cycle. The delay between activate and
write commands is determined by the t
RCD
parameter.
The SDC does not use the auto-precharge function of SDRAMs, which is
enabled by asserting
SA10
high during a read or write command.
Write Command With Data Mask
During partial writes to SDRAM, the
SDQM[1:0]
pins are used to mask
writes to bytes that are not accessed.
shows the
SDQM[1:0]
encodings based on the internal transfer address bit
IA[0]
and the transfer
size.
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 ...
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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 ...