ARM Technical Support Knowledge Articles

CHANGING L51_BANK TO OUTPUT INVERTED SIGNALS

Applies to: C51 C Compiler

Answer


Information in this article applies to:


SYMPTOMS

When creating code banking applications, it may become necessary to output the additional address lines from the L51_BANK.A51 configuration file in a reverse polarity. This may be required if the hardware has inverters in-line with A16, A17, A18, and the other additional address lines.

RESOLUTION

To solve this problem, you must toggle the code bank select lines that will be output. This is done in the L51_BANK.A51 configuration file. The following code illustrates how to do this for PORT-mapped code banking:

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SWITCH          MACRO   N
                ORG     N * 8
                PUBLIC  ?B_SWITCH&N
  ?B_SWITCH&N:
  IF ?B_RTX = 0
                ORL     ?B_CURRENTBANK,#?B_MASK
                ANL     ?B_CURRENTBANK,# (NOT BANK&N OR NOT ?B_MASK)
                RET
  ELSE
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Article last edited on: 2001-02-07 00:00:00

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