AN2148 Motorola / Freescale Semiconductor, AN2148 Datasheet - Page 7

• Manufacturer Part Number: AN2148
• Description: Design Considerations for Interfacing SDRAM with MC68VZ328
• Manufacturer: Motorola / Freescale Semiconductor

Below are some examples of address line configuration for different sizes of SDRAM:
These configurations apply to both 8-bit and 16-bit SDRAM. The reason for this is because differences
between 8-bit and 16-bit addressing can be configured by setting the DRAM Memory Configuration
Register (DRAMMC). See section 7.3 of the VZ User Manual for details on configuring this register. For
details on address bus signals, see section 2.4 of the VZ User Manual.
2.2
One item worth noting for the data bus is that 8-bit SDRAMs should connect their data signals to D[15:8].
For details on data bus signals, see section 2.5 of the VZ User Manual.
2.3
For details on SDRAM interface signals, see section 2.15 of the VZ User Manual.
A[0:9]
A10
A11
A12
BS0
BS1
Data Lines
Interface Lines
SDRAM Pins
1
Note: X = "No Connect"
Note 1: For 16Mbit SDRAM, A11 is used for Bank Select and maybe
labeled as such.
Table 2. Address Line Configurations (8-bit or 16-bit)
Physical Interface Between SDRAM and MC68VZ328
A[1:10]
SDA10
A12
X
X
X
16Mbit
Pre-Publication Draft
A[1:10]
SDA10
A12
X
A13
A14
64Mbit
VZ Pins
A[1:10]
SDA10
A13
X
A12
A15
128Mbit
A[1:10]
SDA10
A12
A13
A15
A16
256Mbit
Data Lines
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