0
1
2
3
M
Bank 0
Row 0
Row 1
Row 2
Row N
C
o
l
l
C
o
l
C
o
l
C
o
Row 0
Row N
Row 1
Row 2
C
C
Bank 1
l
l
0
2
1
o
o
C
C
l
l
3
M
o
o
Row 0
Row N
Row 1
Row 2
C
C
Bank 2
l
l
0
2
1
o
o
l
l
l
l
Row N
Row 2
Row 0
Row 1
Bank P
0
1
2
3
M
C
C
l
l
3
M
o
o
o
C
o
C
o
C
o
C
Architecture
384
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
DDR2/mDDR Memory Controller
Logical Address-to-DDR2/mDDR SDRAM Address Map (continued)
Figure 14-12. DDR2/mDDR SDRAM Column, Row, and Bank Access
NOTE: M is number of columns (as determined by PAGESIZE) minus 1, P is number of banks (as determined by
IBANK) minus 1, and N is number of rows (as determined by both PAGESIZE and IBANK) minus 1.
14.2.5.2 Special Address Mapping (IBANKPOS = 1)
When the internal bank position (IBANKPOS) bit is set to 1, the PAGESIZE, ROWSIZE, and IBANK fields
control the mapping of the logical source address of the memory controller to the column, row, and bank
address bits of the SDRAM device.
shows which source address bits map to the SDRAM
column, row, and bank address bits for all combinations of PAGESIZE, ROWSIZE, and IBANK.
When IBANKPOS is set to 1, the effect of the address-mapping scheme is that as the source address
increments across an SDRAM page boundary, the memory controller proceeds to the next page in the
same bank. This movement along the same bank continues until all the pages have been accessed in the
same bank. The memory controller then proceeds to the next bank in the device. This sequence is shown
in
and
Since, in this address mapping scheme, the memory controller can keep only one bank open, this scheme
is lower in performance than the case when IBANKPOS is cleared to 0. Therefore, this case is only
recommended to be used with Partial Array Self-refresh for mDDR SDRAM where performance may be
traded-off for power savings.
Table 14-6. Address Mapping Diagram for 16-Bit SDRAM (IBANKPOS = 1)
31
Source Address
1
Bank Address
Row Address
Column Address
Number of bank bits is defined by
IBANK nbb = 1, 2, or 3
Number of row bits is defined by
ROWSIZE: nrb = 9, 10, 11, 12, 13, or 14
Number of column bits is defined by
PAGESIZE: ncb = 8, 9, 10, or 11