Z87C33 Datasheet, PDF (46/72 Pages) Zilog, Inc. – CMOS Z8® MCU Consumer Controller Processor

Z87C33
CMOS Z8“ MCU Consumer Controller Processor
40
Table 26. Interrupt Mask Register—IMR FBh/R251 Bank 0h: READ/WRITE
Reset
0
X
X
X
X
X
X
X
Note: R = Read, W = Write, X = Indeterminate.
Bit
Bit
Position Field
Reset
R/W State Description
D7
MIE
R/W
0 Master Interrupt Enable
1: Enable interrupts
0: Disable interrupts
D6
RAM Protect R/W
X RAM Protect
1: Enable RAM Protect*
0: Disable RAM Protect
D5–D0 IRQ5–IRQ0 R/W
X Interrupt Request
1: Enable IRQ0–IRQ5
0: Disable IRQ0–IRQ5
Note: * Must select RAM Protect Mask Option
Flags Register
The CPU sets flags in the Flags Register, FLAGS, to allow the user to perform
tests based on differing logical states. READ/WRITE and reset states for bits D7–
D0 are listed in Table 27.
Table 27. Flags Register—FLAGS FCh/R252 Bank 0h: READ/WRITE
Bit
D7 D6 D5
R/W
R/W R/W R/W
Reset
X
X
X
Note: R = Read, W = Write, X = Indeterminate.
D4
R/W
X
D3
R/W
X
D2
D1
D0
R/W R/W R/W
X
X
X
Bit
Bit
Position Field
D7
Carry
D6
Zero
D5
Sign
D4
Overflow
D3
Decimal Adjust
D2
Half Carry
Note: *Not affected by RESET.
Reset
R/W State Description
R/W
X Carry Flag
R/W
X Zero Flag
R/W
X Sign Flag
R/W
X Overflow Flag
R/W
X Decimal Adjust Flag
R/W
X Half Carry Flag
PS015601-1003