Address Multiplexing; Data Bus - Renesas H8S/2633 Series Hardware Manual

7.5.3

Address Multiplexing

In the case of DRAM space, the row address and column address are multiplexed. With address
multiplexing, the MXC1 and MXC0 bits of the MCR select the amount of shift in the row address.
Table 7-6 shows the relationship between MXC1 and MXC0 settings and the shift amount.
Table 7-6 MXC1 and MXC0 Settings vs Address Multiplexing
MCR
Shift
MXC1 MXC0 Amount
Row 0 0 8 bits
address
1 9 bits
1 0 10 bits
1 Do not set
Column — — —
address
7.5.4

Data Bus

Setting the ABWCR bit of an area set as DRAM space to 1 sets the corresponding area as 8-bit
DRAM space. Clearing the ABWCR bit to 0 sets the area as 16-bit DRAM. 16-bit DRAMs can be
directly connected in the case of 16-bit DRAM space.
With 8-bit DRAM space, the high data bus byte (D15 to D8) is valid. With 16-bit DRAM space,
the high and low data bus bytes (D15 to D0) are valid.
The access size and data alignment are the same as for the standard bus interface. See section
7.4.2, Data Size and Data Alignment for details.
A23 to A13 A12 A11 A10 A9
A23 to A13 A20 A19 A18 A17 A16 A15 A14 A13 A12 A11 A10 A9
A23 to A13 A12 A20 A19 A18 A17 A16 A15 A14 A13 A12 A11 A10 A9
A23 to A13 A12 A11 A20 A19 A18 A17 A16 A15 A14 A13 A12 A11 A10
— — — —
A23 to A13 A12 A11 A10 A9
Address Pin
A8 A7 A6 A5
— — — — —
A8 A7 A6 A5
A4 A3 A2 A1 A0
A8
— — — — —
A4 A3 A2 A1 A0
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