3 other registers, Figure 818. end-of-interrupt register in slave mo, Figure 819. request, mask, and in-service registe – Intel 80C188XL User Manual
Page 223
INTERRUPT CONTROL UNIT
8-28
Figure 8-18. End-of-Interrupt Register in Slave Mode
8.5.1.3
Other Registers
The Priority Mask register is identical in Slave mode and Master mode. The Interrupt Request,
Interrupt Mask, and In-Service registers retain the same function, but individual bits differ to ac-
commodate the addition of the individual timer interrupts and the deletion of the external inter-
rupts. Figure 8-19 shows the bit positions for Slave mode.
Figure 8-19. Request, Mask, and In-Service Registers
Register Name:
End-of-Interrupt Register (in Slave Mode)
Register Mnemonic:
EOI
Register Function:
Used to issue the EOI command
Bit
Mnemonic
Bit Name
Reset
State
Function
VT2:0
Interrupt
Type
0
Write the three LSBs of the interrupt type (see
Table 8-5) to these bits to issue an EOI
command in slave mode.
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.
A1197-A0
15
0
V
T
0
V
T
2
V
T
1
15
0
T
M
R
0
D
M
A
0
D
M
A
1
T
M
R
2
T
M
R
1