Hitachi H8/500 Series - Interrupt Handling Flowchart

Program execution state
Interrupt requested?
Y
N
N
N
N
N
N
N
NNN
Y
Y
Y
Y
Y
Y
Y
YY
Y
N
N
Y
Y
N
N
N
N
Y
Y
Y
N
Address
error?
Trace?
NMI?
Level-7 interrupt?
Level-6 interrupt?
Level-1 interrupt?
Mask level
in SR 6?
Mask level
in SR 5?
Mask level
in SR = 0?
Data transfer
enabled?
Interrupt remains pending
Start DTC
Read DTC vector
Read transfer mode
Read source address
Read data
Source
address increment
mode?
Increment source
address (+1 or +2)
Write source address
Read destination address
Write data
Exception-handling
sequence
Save PC
Maximum
mode?
Save SR
Save PC
Clear T bit
Trace
Address
error?
Update mask level
Vectoring
Destination
address increment
mode?
Write destination
address
Increment source
address (+1 or +2)
Read DTCR
DTCR-1 DTCR
→
Write DTCR
DTCR = 0?
To user-coded
exception-handling
routine
≤
≤
Figure 5-2 Interrupt Handling Flowchart
106
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