DDR Bridge
Microsemi Proprietary UG0446 User Guide Revision 7.0
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The default address is 0×A000. If the non-bufferable region size and address is left as default then
the 64 KB memory from 0×A0000000 address to 0×A0010000 address will be
non-bufferable.
•
Enable or disable respective buffers allocated for each master
: The selection of disabling the
write/read buffer makes all transactions without buffering. By default buffering is enabled.
•
DDR burst size for read/write buffers
: The DDR bridge configurator allows to select the size of
read/write buffers as 32 bytes or 16 bytes.
Figure 135 •
Configuring MSS DDR Bridge
5.5.0.2
MDDR/FDDR DDR Bridge Configurations
The DDR bridge in the MDDR or FDDR subsystem can be configured through the DDR_FIC registers
shown in
. The possible configurations and corresponding registers are as
follows:
•
Enable or disable the write and read buffers of the DDR bridge using the
DDR_FIC_HPD_SW_RW_EN_CR register.
•
Configure buffer size to 32 bytes or 16 bytes using the DDR_FIC_NBRWB_SIZE_CR register.
•
Configure the non-bufferable address using the DDR_FIC_NB_ADD register.
•
Configure the non-bufferable size using the DDR_FIC_NBRWB_SIZE_CR register.
•
Configure the timeout value for each write buffer using the
DDR_FIC_LOCK_TIMEOUTVAL_1_CR and DDR_FIC_LOCK_TIMEOUTVAL_2_CR registers. Set
the timeout value to maximum or a non- zero value.
The configuration registers for the MDDR DDR bridge and FDDR DDR bridge are also listed under the
DDR FIC registers
section in the
MDDR and FDDR chapters
.
5.5.1
Use Model 1: High Speed Data Transactions from Cortex-M3
Processor
This use model shows the use of the DDR bridge for increasing throughput from the Cortex-M3
processor to external DDR memories. The Cortex-M3 processor performs only the single read and write
transactions-not the burst transactions. The DDR bridge converts these single transactions into burst
transactions and further increases the throughput. The buffers for DS and IDC masters are enabled for
this, and the non-bufferable size is selected as
None
, as shown in the following image.