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PROBLEMS WITH EARLY CYGNAL SILICON

Applies to: RTX51 Tiny Real-time Kernel

Answer


Information in this article applies to:


QUESTION

Are there any problems using Cygnal devices with the RTX51 Tiny RTOS?

ANSWER

Yes. Some early versions of Cygnal devices required at least one instruction to execute after selecting a new register bank in the PSW before using one of the single-byte MOV Rn, A instructions. Such a construct is found in the RTX51 Tiny kernel. Source code is provided so you can easily correct this problem. In the RTX51TNY.A51 source file, you must change the following code:

TIMERINT:       CALL    RETINT          ; Enable Interrupts again.
                MOV     ?RTX_SAVEPSW,PSW
                MOV     PSW,#?RTX_REGISTERBANK
                MOV     saveacc,A

to this:

TIMERINT:       CALL    RETINT          ; Enable Interrupts again.
                MOV     ?RTX_SAVEPSW,PSW
                MOV     PSW,#?RTX_REGISTERBANK
                MOV     saveacc,ACC

RTX51 Tiny Version 2 will be updated to avoid this sequence of instructions.

Note: This problem does not exist in later revisions of the Cygnal silicon.

Article last edited on: 2004-04-20 13:18:41

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