T89C51RD2-3CBC-L ATMEL [ATMEL Corporation], T89C51RD2-3CBC-L Datasheet - Page 37

• Manufacturer Part Number: T89C51RD2-3CBC-L
• Description: 0 to 40MHz Flash Programmable 8-bit Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

6.7. Interrupt System
The T89C51RD2 has a total of 7 interrupt vectors: two external interrupts (INT0 and INT1), three timer interrupts
(timers 0, 1 and 2), the serial port interrupt and the PCA global interrupt. These interrupts are shown in Figure 16.
Each of the interrupt sources can be individually enabled or disabled by setting or clearing a bit in the Interrupt
Enable register (See Table 18.). This register also contains a global disable bit, which must be cleared to disable
all interrupts at once.
Each interrupt source can also be individually programmed to one out of four priority levels by setting or clearing
a bit in the Interrupt Priority register (See Table 19.) and in the Interrupt Priority High register (See Table 20.).
shows the bit values and priority levels associated with each combination.
The PCA interrupt vector is located at address 0033H. All other vectors addresses are the same as standard C52
devices.
Rev. F - 15 February, 2001
EXF2
INT0
INT1
PCA IT
TF0
TF1
TF2
RI
TI
Individual Enable
IE0
IE1
Figure 16. Interrupt Control System
IPH, IP
3
0
3
0
3
0
3
0
3
0
3
0
3
0
Global Disable
T89C51RD2
High priority
interrupt
Interrupt
polling
sequence, decreasing
from high to low priority
Low priority
interrupt
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