upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 397

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

CHAPTER 13 INTERRUPT FUNCTIONS
Cautions 3. Use the 1-bit memory manipulation instruction (CLR1) for manipulating the flag of the
interrupt request flag register. A 1-bit manipulation instruction such as “IF0L.0 = 0;” and
“_asm(“clr1 IF0L, 0”);” should be used when describing in C language, because assembly
instructions after compilation must be 1-bit memory manipulation instructions (CLR1).
If an 8-bit memory manipulation instruction “IF0L & = 0xfe;” is described in C language, for
example, it is converted to the following three assembly instructions after compilation:
mov a, IF0L
and a, #0FEH
mov IF0L, a
In this case, at the timing between “mov a, IF0L” and “mov IF0L, a”, if the request flag of
another bit of the identical interrupt request flag register (IF0L) is set to 1, it is cleared to 0 by
“mov IF0L, a”. Therefore, care must be exercised when using an 8-bit memory manipulation
instruction in C language.
397
Preliminary User’s Manual U19014EJ1V0UD