
70
AT89C51ID2
4289C–8051–11/05
Table 55. IPH1 Register
IPH1 - Interrupt Priority High Register (B3h)
Reset Value = XXXX X000b
Not bit addressable
76
543
210
-
SPIH
TWIH
KBDH
Bit
Number
Bit
Mnemonic
Description
7-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
6-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
5-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
4-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
3-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
2
SPIH
SPI interrupt Priority High bit
SPIH
SPILPriority Level
0
0Lowest
0
1
0
1
1Highest
1TWIH
TWI interrupt Priority High bit
TWIH
TWILPriority Level
0
0Lowest
0
1
0
1
1Highest
0
KBDH
Keyboard interrupt Priority High bit
KB DH
KBDLPriority Level
00 Lowest
0
1
10
1
1Highest