MSM82C59A-2JS View Datasheet(PDF) - Oki Electric Industry
Part Name
Description
MFG CO.
'MSM82C59A-2JS' PDF : 28 Pages View PDF
¡ Semiconductor
MSM82C59A-2RS/GS/JS
Before Rotation
(IR4 the highest priority requesting service)
IS Status
IS7 IS6 IS5 IS4 IS3 IS2 IS1 IS0
01010000
Priority Status 7 6 5 4 3 2 1 0
Lowest
Highest
After Rotation
(IR4 was serviced, all other priorities rotated correspondingly)
IS Status
IS7 IS6 IS5 IS4 IS3 IS2 IS1 IS0
01000000
Priority Status 2 1 0 7 6 5 4 3
Highest
Lowest
(11) Specific Rotation (Specific Priority)
All priority levels can be changed by programming the lowest priority level (Set Priority
Command in OCW2). For example, if IR5 is programmed as the device of lowest priority,
IR6 will have the highest priority. In this mode, the internal status can be updated during
OCW2 by software control. This is unrelated, however, to the EOI command in the same
OCW2.
Priority level can also be changed by using the OCW2 Rotate On Specific EOI command.
(12) Interrupt Mask
Interrupt inputs can be masked individually by Interrupt Mask Registers (IMR)
programmed through the OCW1. Each interrupt channel is masked (disabled) when the
respective IMR bit is set to “1”. IR0 is masked by bit 0, and IR1 is masked by bit 1. Masking
of any particular channel has no effect on other channels.
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