Software Considerations

10.Make sure that no other devices respond in the range from $00000000 to $40000000.

Then, for each block:

1.Set the block’s base address to $00000000.

2.Enable the block and make sure that the other three blocks are disabled.

3.Set the block’s size control bits. Start with the largest possible (1024MB).

4.Write differing 64-bit data patterns to certain addresses within the block. The data patterns do not matter as long as each 64-bit data pattern is unique. The addresses to be written vary depending on the size that is currently being checked and are specified in Table 3-18. Table 3-19shows how PowerPC addresses correspond to DRAM row/column addresses.

5.Read back all of the addresses that have been written.

If all of the addresses still contain exactly what was written, then the block’s size has been found. It is the size for which the block is currently programmed.

If any of the addresses do not match exactly, then the amount of memory is less than that for which it is currently programmed. Sizing needs to continue for this block by programming its control bits to the next smaller size and repeating steps 4 and 5.

6.If no match is found for any size, then the block is unpopulated and has a size of 0MB.

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Motorola MVME2300 Series manual Software Considerations