S3C8245/P8245/C8249/P8249 CONTROL REGISTER
4-41
SYM System Mode Register DEHSet 1
Bit Identifier .7 .6 .5 .4 .3 .2 .1 .0
nRESET Value 0––xxx0 0
Read/Write R/W R/W R/W R/W R/W R/W
Addressing Mode Register addressing mode only
.7 Not used, But you must keep "0"
.6–.5 Not used for the S3C8245/C8249
.4.2 Fast Interrupt Level Selection Bits (1)
000IRQ0
001IRQ1
010IRQ2
011IRQ3
100IRQ4
101IRQ5
110IRQ6
111IRQ7
.1 Fast Interrupt Enable Bit (2)
0Disable fast interrupt processing
1Enable fast interrupt processing
.0 Global Interrupt Enable Bit (3)
0Disable all interrupt processing
1Enable all interrupt processing
NOTES:
1.You can select only one interrupt level at a time for fast interrupt processing.
2.Setting SYM.1 to "1" enables fast interrupt processing for the interrupt level currently selected by SYM.2–SYM.4.
3.Following a reset, you must enable global interrupt processing by executing an EI instruction
(not by writing a "1" to SYM.0).