M37702E6BFS Renesas Electronics America, M37702E6BFS Datasheet - Page 90

• Manufacturer Part Number: M37702E6BFS
• Description: EPROM MCU/8BIT CMOS EMULATION CH
• Manufacturer: Renesas Electronics America

Specifications of M37702E6BFS

• Accessory Type: Emulator EPROM MCU
• For Use With/related Products: 7702
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

INTERRUPTS
4.11 Precautions when using interrupts
4.11 Precautions when using interrupts
Fig. 4.11.1 Program example to reserve time required for changing interrupt priority level
Table 4.11.1 Relation between number of instructions to be inserted with program example of Figure
4.11.1 and interrupt priority detection time select bits
Note: We recommend [b5 = “1”, b4 = “0”].
4–26
Interrupt priority detection time select bits (Note)
1. Use the SEB or CLB instruction when setting the interrupt control registers (addresses 70
2. To change the interrupt priority level select bits (bits 0 to 2 at addresses 70
7F
of
change. Accordingly, it is necessary to reserve enough time by software when changing the
interrupt priority level of which interrupt source is the same within a very short execution time
consisting of a few instructions.
Figure 4.11.1 shows a program example to reserve time required for changing interrupt priority
level. The time for change depends on the interrupt priority detection timer select bits (bits 4 and
5 at address 5E
with program example of Figure 4.11.1 and the interrupt priority detection time select bits.
b5
0
0
1
1
Note: All instructions (other than instructions for writing to address 7X
16
:
SEB .B #0XH, 007XH
NOP
NOP
NOP
CLB.B #0XH, 007XH
:
.)
are required after executing an write-instruction until completion of the interrupt priority level’s
same cycles as NOP instruction can also be inserted. Confirm the number of
instructions to be inserted by Table 4.11.1.
16
). Table 4.11.1 lists the relation between the number of instructions to be inserted
; Write to interrupt priority level select bits
; Insert NOP instruction (Note)
;
;
; Write to interrupt priority level select bits
b4
0
1
0
1
7702/7703 Group User’s Manual
7 cycles of
4 cycles of
2 cycles of
Do not select.
Interrupt priority level
detection time
16
) which have the
NOP instruction 4 or more
NOP instruction 2 or more
NOP instruction 1 or more
Number of inserted
16
to 7F
instructions
16
), 2 to 7 cycles
16
to