Fujitsu FR60 Hardware Manual page 380

CHAPTER 11 REALOS-RELATED HARDWARE
■ Save/Restore Processing
If it is necessary to save and restore the internal state of the bit search module, such as when the bit search
module is used in an interrupt handler, use the following procedure:
1. Read the 1 detection data register and save its contents (save).
2. Use the bit search module.
3. Write the data saved in 1) to the 1 detection data register (restore).
With the above operation, the value obtained when the detection result register is read the next time
corresponds to the value written to the bit search module before 1).
If the data register written to last is the 0 detection or change point detection register, the value is restored
correctly with the above procedure.
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