HD6417034B RENESAS [Renesas Technology Corp], HD6417034B Datasheet - Page 121

• Manufacturer Part Number: HD6417034B
• Description: 32-Bit RISC Microcomputer
• Manufacturer: RENESAS [Renesas Technology Corp]

6.5.3
If a break is attempted at the task A return destination instruction fetch, task B is activated before
the UBC interrupt by interrupt B generated during task A processing, and the UBC interrupt is
handled after the interrupt B exception handling.
1. Cause
2. Remedy
The SH7032/SH7034 chip operates as follows.
It actually takes at least two cycles for the UBC interrupt generated by the address 0x00011a0c
instruction fetch cycle to be sent to the interrupt controller and interrupt exception handling to
begin. However, as shown in figure 6.3, when the UBC interrupt is generated, previously
generated interrupt B initiated by task B is accepted first, and the UBC interrupt is accepted
after completion of the interrupt B exception handling.
There is no way of preventing this operation by hardware. A software solution, such as the use
of a flag, must be employed.
Break
condition
Instruction Fetch Break
0x02000030
0x00011a0a
0x00011a0c
(0xf000978 Overrun fetch)
<Address>
0xf000974
Interrupt B accepted
Instruction replaced by interrupt
exception handling
Task B first instruction fetch
UBC first instruction fetch
Overrun fetch
<Description>
(instruction replaced by interrupt
exception handling)
F D
Figure 6.3 UBC Operation
F
E E
Interrupt exception
handling
M M E
UBC interrupt accepted
M E E
Rev. 7.00 Jan 31, 2006 page 95 of 658
Section 6 User Break Controller (UBC)
F
D E E
f
Interrupt exception
M M
handling
REJ09B0272-0700
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M
E E
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