AMD Am186TMER Microscope & Magnifier User Manual


 
Interrupt Control Unit
8-34
8.4.7 Priority Mask Register (PRIMSK, Offset 2Ah)
(Slave Mode)
The format of the Priority Mask Register is shown in Figure 8-23. The Priority Mask Register
provides the value that determines the minimum priority level at which maskable interrupts
can generate an interrupt.
Figure 8-23 Priority Mask Register (PRIMSK, offset 2Ah)
The value of the PRIMSK Register at reset is 0007h.
Bits 15–3: Reserved
Bits 2–0: Priority Field Mask (PRM2–PRM0)—This field determines the minimum priority
which is required for a maskable interrupt source to generate an interrupt.
A value of seven (111b) allows all interrupt sources that are not masked to generate
interrupts. A value of five (101b) allows only unmasked interrupt sources with a
programmable priority of zero to five (000b to 101b) to generate interrupts.
Table 8-6 Priority Field Mask (Slave Mode)
Priority PR2–PR0
(High) 0 0 0 0b
10 0 1b
20 1 0b
30 1 1b
41 0 0b
51 0 1b
61 1 0b
(Low) 7 1 1 1b
15
70
PRM0
PRM2
PRM1
Reserved