AT43USB326-AU Atmel, AT43USB326-AU Datasheet - Page 20

• Manufacturer Part Number: AT43USB326-AU
• Description: IC USB KEYBOARD CTRLR 48LQFP
• Manufacturer: Atmel
• Series: AVR®r

Specifications of AT43USB326-AU

• Applications: Keyboard Controller
• Core Processor: AVR
• Program Memory Type: Mask ROM (16 kB)
• Controller Series: AT43USB
• Ram Size: 512 x 8
• Interface: USB
• Number Of I /o: 32
• Voltage - Supply: 4.4 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 5. AT43USB326 Interrupt Structure
Reset Sources
20
AT43USB326
GLB SUSP
FRMWUP
EOF2
HEP0
FEP2
FEP1
FEP0
RSM
SOF
The AT43USB326 has four sources of reset:
•
•
•
•
Suspend/Resume
USB Interrupt
Flag Register
Power-on Reset – The MCU is reset when the supply voltage is below the power-on reset
threshold.
External Reset – The MCU is reset when a low level is present on the RESET pin for
more than 50 ns.
Watchdog Reset – The MCU is reset when the watchdog timer period expires and the
watchdog is enabled.
USB Reset – The AT43USB326 has a feature to separate the USB and microcontroller
resets. This feature is enabled by setting the BUS INT EN, bit 3 of the SPRSIE register. A
USB bus reset is defined as a SE0 (single ended zero) of at least 4 slow speed USB clock
cycles received by Port0. The internal reset pulse to the USB hardware and
microcontroller lasts for 24 oscillator periods.
–
–
Register
Resets not separated: A USB bus reset will also reset the microcontroller.
Separated reset: A USB bus reset will only reset the USB hardware, while an
interrupt to the microcontroller will be generated if the BUS INT MSK bit, bit 3 of
SPRSMSK register, is also set.
Enable Register
Suspend/Resume
Interrupt Enable
USB Interrupt
Register
Suspend/Resume
Mask Register
USB Interrupt
Interrupt Mask
Register
TIMER0 OVF
USB
RESET
INT0
Microcontroller
13
8
2
1
Interrupt
Logic
3313D–USB–04/06