pt7a6525 Pericom Technology Inc, pt7a6525 Datasheet - Page 37

• Manufacturer Part Number: pt7a6525
• Description: Pt7a6525/6525l/6526 Hdlc Controller
• Manufacturer: Pericom Technology Inc

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Interrupt Status Register (ISTA)
Mask Register (MASK)
Each interrupt source can be selectively masked by setting the respective bit in MASK (whose bit positions correspond to those
in ISTA register). Masked interrupts are not indicated when reading ISTA. Instead, they are internally stored and will be indicated
after the corresponding MASK bits are reset.
Note: In the event of an extended interrupt, no interrupt request will be generated with EXA, EXB bits masked, even though this
bit is set in ISTA.
PT0017(12/05)
Table 11. Description of Interrupt Status Register
Note:
The ICA, EXA, and EXB bits are present in channel B only and correspond to the ISTA -A, EXIR-A and EXIR -B registers.
After the PT7A6526 requests an interrupt by changing its INT pin to logic 0, the microprocessor must first read the ISTA
register of channel B and check the state of these bits in order to determine which interrupt source(s) caused the interrupt.
Multiple interrupt sources may cause only a single interrupt request.
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