ADSP-BF535 Blackfin Processor Hardware Reference
18-11
External Bus Interface Unit
For external devices that need a clock, the
CLKOUT
pin can be enabled by
setting the
AMCKEN
bit in the
EBIU_AMGCTL
register. In systems that do not
use
CLKOUT
, set the
AMCKEN
bit to zero.
The
BxPEN
bits allow software to enable 16-bit packing mode for each
bank independently. When 16-bit packing is enabled,
ABE[3]
becomes
ADDR[1]
and
ABE[2]
is held deasserted. Only the lower 16 bits of the exter-
nal data bus are used,
DATA[15:0]
.
In 16-bit packing mode, 32-bit transactions to AMC space that are
requested on internal buses are converted to two sequential 16-bit accesses
on the external bus. All 8-bit and 16-bit requests are still processed with a
single external transaction. When 32-bit packing is enabled, all 32-bit
transactions are processed with a single transfer.
Figure 18-3. Asynchronous Memory Global Control Register
15 14
13 12
11 10
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
Asynchronous Memory Global Control Register (EBIU_AMGCTL)
AMBEN[1:0]
B0PEN
AMCKEN
B1PEN
B2PEN
B3PEN
0 - Disable CLKOUT for
asynchronous memory
region accesses
1 - Enable CLKOUT for
asynchronous memory
region accesses
Bank 3 16-bit packing enable
0 - 32-bit datapath enabled
1 - 16-bit packing enabled
Bank 2 16-bit packing enable
0 - 32-bit datapath enabled
1 - 16-bit packing enabled
Bank 1 16-bit packing enable
0 - 32-bit datapath enabled
1 - 16-bit packing enabled
Bank 0 16-bit packing enable
0 - 32-bit datapath enabled
1 - 16-bit packing enabled
Enable asynchronous
memory banks
00 - All banks disabled
01 - Bank0 enabled
10 - Bank0 and Bank1
enabled
11 All banks enabled
Reset = 0x00F2
0xFFC0 3C00
Summary of Contents for ADSP-BF535 Blackfin
Page 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Page 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Page 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Page 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Page 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Page 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Page 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Page 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Page 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Page 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Page 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...