11
8xC251Tx Hardware Description
3.2.6 IE1
Address: B1H
Reset Value: xxxx xxx0B
3.2.7 IPH1
Address: B3H
Reset Value: xxxx xxx0B
3.2.8 IPL1
Address: B2H
Reset Value: xxxx xxx0B
Interrupt priority o f the s econd s erial I/O port ca n be prog rammed to one o f four l evels de pending on the
IPH1.0 and IPL1.0 bits.
Table 8. IE1 Spec ial Function Register Defin itions
Bit Number Bit Mne-
monic Function
7 - 1 -Reserved
0ES1 Second serial I/O port Interr upt Enable:
Setting this bit enables the second serial I/O port in terrupt
Table 9. IPH1 Special Function Register Definitions
Bit Number Bit Mne-
monic Function
7 - 1 -Reserved
0IPH1.0 Second serial I/O port Inte rrupt Priority High Bit
Table 10. IPL1 Special Function Regi ster Definitions
Bit Number Bit Mne-
monic Function
7 - 1 -Reserved
0IPL1.0 Second serial I/O port Inte rrupt Priority Low Bit
Table 11. Interrupt Priority of Second Serial I/O Port
IPH1.0 IPL1.0 Priority Level
000 (Lowest Priority)
011
102
113 (Highest Priori ty)