atmega163l ATMEL Corporation, atmega163l Datasheet - Page 34

• Manufacturer Part Number: atmega163l
• Description: Atmega163 8-bit Avr Microcontroller With 16k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

MCU Control Register –
MCUCR
34
ATmega163(L)
The MCU Control Register contains control bits for general MCU functions.
• Bit 7 – Res: Reserved Bit
This bit is a reserved bit in the ATmega163 and always reads as zero.
• Bit 6 – SE: Sleep Enable
The SE bit must be set (one) to make the MCU enter the sleep mode when the SLEEP
instruction is executed. To avoid the MCU entering the sleep mode unless it is the pro-
grammers purpose, it is recommended to set the Sleep Enable SE bit just before the
execution of the SLEEP instruction.
• Bits 5, 4 – SM1/SM0: Sleep Mode Select Bits 1 and 0
These bits select between the three available sleep modes as shown in Table 7.
Table 7. Sleep Mode Select
• Bits 3, 2 – ISC11, ISC10: Interrupt Sense Control 1 Bit 1 and Bit 0
The External Interrupt 1 is activated by the external pin INT1 if the SREG I-Flag and the
corresponding interrupt mask in the GIMSK are set. The level and edges on the external
INT1 pin that activate the interrupt are defined in Table 8. The value on the INT1 pin is
sampled before detecting edges. If edge or toggle interrupt is selected, pulses that last
longer than one clock period will generate an interrupt. Shorter pulses are not guaran-
teed to generate an interrupt. If low level interrupt is selected, the low level must be held
until the completion of the currently executing instruction to generate an interrupt.
Table 8. Interrupt 1 Sense Control
Bit
$35 ($55)
Read/Write
Initial Value
ISC11
0
0
1
1
SM1
0
0
1
1
ISC10
0
1
0
1
R
7
–
0
Description
The low level of INT1 generates an interrupt request.
Any logical change on INT1 generates an interrupt request.
The falling edge of INT1 generates an interrupt request.
The rising edge of INT1 generates an interrupt request.
R/W
SE
SM0
6
0
0
1
0
1
SM1
R/W
5
0
Sleep Mode
Idle
ADC Noise Reduction
Power-down
Power-save
SM0
R/W
4
0
ISC11
R/W
3
0
ISC10
R/W
2
0
ISC01
R/W
1
0
ISC00
R/W
0
0
1142E–AVR–02/03
MCUCR