Rainbow Electronics T89C5115 - Manual (Page 85)

85
T89C5115
4128A–8051–04/02
Table 60. Priority Level Bit Values
A low-priority interrupt can be interrupted by a high priority interrupt but not by another
low-priority interrupt. A high-priority interrupt cannot be interrupted by any other interrupt
source.
If two interrupt requests of different priority levels are received simultaneously, the
request of the higher priority level is serviced. If interrupt requests of the same priority
level are received simultaneously, an internal polling sequence determines which
request is serviced. Thus within each priority level there is a second priority structure
determined by the polling sequence, see Table 61.
Table 61. Interrupt Priority Within Level
IPH.x IPL.x Interrupt Level Priority
0 0 0 (Lowest)
0 1 1
1 0 2
1 1 3 (Highest)
Interrupt Name Interrupt Address Vector Priority Number
external interrupt (INT0) 0003h 1
Timer0 (TF0) 000Bh 2
external interrupt (INT1) 0013h 3
Timer1 (TF1) 001Bh 4
PCA (CF or CCFn) 0033h 5
UART (RI or TI) 0023h 6
Timer2 (TF2) 002Bh 7
ADC (ADCI) 0043h 8