Intel 80C188XL, 80C186XL 8.4.6Poll and Poll Status Registers, Register Name, Register Mnemonic

INTERRUPT CONTROL UNIT

Register Name:	In-Service Register
Register Mnemonic:	INSERV
Register Function:	Indicates which interrupt handlers are in process

15

I	I	I	I
N	N	N	N
T	T	T	T
3	2	1	0

DD M M A A 1 0

0

T

M

R

			A1192-A0
Bit	Bit Name	Reset	Function
Mnemonic		State
INT3:0	External	0000 0	A bit is set to indicate that the corresponding
	Interrupt In-		external interrupt is being serviced.
	Service
DMA1:0	DMA	0	This bit is set to indicate that the corresponding
	Interrupt In-		DMA channel interrupt is being serviced.
	Service
TMR	Timer	0	This bit is set to indicate that a timer interrupt is
	Interrupt In-		being serviced.
	Service

NOTE: Reserved register bits are shown with gray shading. Reserved bits must be written to a logic zero to ensure compatibility with future Intel products.

Figure 8-10. In-Service Register

8.4.6Poll and Poll Status Registers

The Poll and Poll Status registers allow you to poll the Interrupt Control Unit and service inter- rupts through software. You can read these registers to determine whether an interrupt is pending and, if so, the interrupt type. The registers contain identical information, but reading them pro- duces different results.

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