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Do registers in 4-MB mode of memory expansion reflected to CS1 to CS3?

Latest Updated:07/16/2010

Question:

In 4-MB mode of the memory expansion function, is the wait that is set in the CS0 area by the external area wait control expansion register* and the chip select expansion control register also reflected to the CS1 to CS3 areas (areas other than the CS area)?

Answer:

Yes, it is reflected.
In 4-MB mode, when areas other than the CS area are accessed, a low level signal is output from the CS0 pin, and a bank number is output from the CS3 to CS1 pins.

  • CS0: chip select signal
  • CS1 to CS3: bank number output (set by the bank select bit in the data bank register)

At this time, the wait set in the CS0 area by the external area wait control expansion register and the chip select expansion control register is reflected to the areas other than the CS area (CS1 to CS3 areas).
It is not necessary to set waits to the CS1 to CS3 pins individually.

*: The external area wait control expansion register may not available in some products.

Suitable Products
M16C/62P(M16C/62PT)
M16C/63
M16C/64A
M16C/65