AT89S52 Atmel Corporation, AT89S52 Datasheet - Page 18

• Manufacturer Part Number: AT89S52
• Manufacturer: Atmel Corporation

Specifications of AT89S52

• Flash (kbytes): 8 Kbytes
• Max. Operating Frequency: 24 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Uart: 1
• Sram (kbytes): 0.25
• Operating Voltage (vcc): 4.0 to 5.5
• Timers: 3
• Isp: SPI
• Watchdog: Yes

Table 13-1.
Figure 13-1. Interrupt Sources
18
Symbol
EA
–
ET2
ES
ET1
EX1
ET0
EX0
User software should never write 1s to reserved bits, because they may be used in future AT89 products.
(MSB)
Enable Bit = 1 enables the interrupt.
Enable Bit = 0 disables the interrupt.
EA
AT89S52
Interrupt Enable (IE) Register
Position
IE.7
IE.6
IE.5
IE.4
IE.3
IE.2
IE.1
IE.0
–
ET2
EXF2
INT0
INT1
TF0
TF1
TF2
RI
TI
Function
Disables all interrupts. If EA = 0, no interrupt is acknowledged. If EA = 1, each
interrupt source is individually enabled or disabled by setting or clearing its enable bit.
Reserved.
Timer 2 interrupt enable bit.
Serial Port interrupt enable bit.
Timer 1 interrupt enable bit.
External interrupt 1 enable bit.
Timer 0 interrupt enable bit.
External interrupt 0 enable bit.
0
1
0
1
ES
(LSB)
ET1
IE0
IE1
EX1
ET0
EX0
1919D–MICRO–6/08