AT89C51RC-24JI Atmel, AT89C51RC-24JI Datasheet - Page 18
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AT89C51RC-24JI
Manufacturer Part Number
AT89C51RC-24JI
Description
IC MICRO CTRL 24MHZ 44PLCC
Manufacturer
Atmel
Series
89Cr
Datasheet
1.AT89C51RC-24PU.pdf
(36 pages)
Specifications of AT89C51RC-24JI
Core Processor
8051
Core Size
8-Bit
Speed
24MHz
Connectivity
SPI, UART/USART
Peripherals
WDT
Number Of I /o
32
Program Memory Size
32KB (32K x 8)
Program Memory Type
FLASH
Ram Size
512 x 8
Voltage - Supply (vcc/vdd)
4 V ~ 5.5 V
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
44-PLCC
For Use With
AT89STK-11 - KIT STARTER FOR AT89C51RX2
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Eeprom Size
-
Data Converters
-
Other names
AT89C51RC24JI
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
16. Interrupts
18
AT89C51RC
The AT89C51RC has a total of six interrupt vectors: two external interrupts (INT0 and INT1),
three timer interrupts (Timers 0, 1, and 2), and the serial port interrupt. These interrupts are all
shown in
Each of these interrupt sources can be individually enabled or disabled by setting or clearing a
bit in Special Function Register IE. IE also contains a global disable bit, EA, which disables all
interrupts at once.
Note that
write 1s to these bit positions, since they may be used in future AT89 products.
Timer 2 interrupt is generated by the logical OR of bits TF2 and EXF2 in register T2CON. Nei-
ther of these flags is cleared by hardware when the service routine is vectored to. In fact, the
service routine may have to determine whether it was TF2 or EXF2 that generated the interrupt,
and that bit will have to be cleared in software.
The Timer 0 and Timer 1 flags, TF0 and TF1, are set at S5P2 of the cycle in which the timers
overflow. The values are then polled by the circuitry in the next cycle. However, the Timer 2 flag,
TF2, is set at S2P2 and is polled in the same cycle in which the timer overflows.
Table 16-1.
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
Figure
Table 14-1
Interrupt Enable (IE) Register
16-1.
–
shows that bit position IE.6 is unimplemented. User software should not
Position
IE.7
IE.6
IE.5
IE.4
IE.3
IE.2
IE.1
IE.0
ET2
ES
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.
ET1
(LSB)
EX1
ET0
1920D–MICRO–6/08
EX0