AT43USB325E-AU Atmel, AT43USB325E-AU Datasheet - Page 30

• Manufacturer Part Number: AT43USB325E-AU
• Description: IC USB KEYBOARD CTRLR 64LQFP
• Manufacturer: Atmel
• Series: AVR®r

Specifications of AT43USB325E-AU

• Applications: Keyboard Controller
• Core Processor: AVR
• Program Memory Type: SRAM (16 kB)
• Controller Series: AT43USB
• Ram Size: 512 x 8
• Interface: SPI, 3-Wire Serial
• Number Of I /o: 42
• Voltage - Supply: 4.4 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

4.11.1
30
AT43USB325
MCU Control Register – MCUCR
from an interrupt, it will always return to the main program and execute one more instruction
before any pending interrupt is served.
• Bit 7, 6 – Res: Reserved Bits
• Bit 5 – SE: Sleep Enable
The SE bit must be set (1) 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 programmer's purpose,
it is recommended to set the Sleep Enable SE bit just before the execution of the SLEEP
instruction.
• Bit 4 – SM: Sleep Mode
This bit selects between the two available sleep modes. When SM is cleared (zero), Idle Mode is
selected as Sleep Mode. When SM is set (1), Power Down mode is selected as sleep mode. The
AT43USB325 does not support the Idle Mode and SM should always be set to one when enter-
ing the Sleep Mode.
• Bit 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 corre-
sponding interrupt mask in the GIMSK is set. The level and edges on the external INT1 pin that
activate the interrupt are defined in the following table:
Table 4-2.
Read/Write
Initial Value
$35 ($55)
ISC11
Bit
0
0
1
1
INT1 Sense Control
R
7
–
0
ISC10
0
1
0
1
R
6
–
0
Description
The low level of INT1 generates an interrupt request.
Reserved.
The falling edge of INT1 generates an interrupt request.
The rising edge of INT1 generates an interrupt request.
R/W
SE
5
0
R/W
SM
4
0
ISC11
R/W
3
0
ISC10
R/W
2
0
R
1
–
0
R
0
–
0
3355C–USB–4/05
MCUCR