CONTROL REGISTERS
S3C80A5B
4-10
IMR
— Interrupt Mask Register
DDH
Set 1
Bit Identifier
.7
.6
.5
.4
.3
.2
.1
.0
RESET Value
x
x
x
x
x
x
x
x
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Addressing Mode
Register addressing mode only
.7
Interrupt Level 7 (IRQ7) Enable Bit; External Interrupts P0.7–P0.4
1
Enable (un-mask)
.6
Interrupt Level 6 (IRQ6) Enable Bit; External Interrupts P0.3–P0.0
0
Disable (mask)
1
Enable (un-mask)
.5
Not used for S3C80A5B.
.4
Interrupt Level 4 (IRQ4) Enable Bit; Counter A Interrupt
0
Disable (mask)
1
Enable (un-mask)
.3–.2
Not used for S3C80A5B.
.1
Interrupt Level 1 (IRQ1) Enable Bit; Timer 1 Match or Overflow
0
Disable (mask)
1
Enable (un-mask)
.0
Interrupt Level 0 (IRQ0) Enable Bit; Timer 0 Match or Overflow
0
Disable (mask)
1
Enable (un-mask)
NOTES:
1. When an interrupt level is masked, any i nterrupt requests that may be issued are not recognized by the CPU.
2. Interrupt levels IRQ2, IRQ3 and IRQ5 are not used in the S3C80A5B interrupt structure.