at43usb355 ATMEL Corporation, at43usb355 Datasheet - Page 22

• Manufacturer Part Number: at43usb355
• Description: At43usb355 Full-speed Usb Microcontroller With Embedded Hub, Adc And Pwm
• Manufacturer: ATMEL Corporation

Figure 8. AT43USB355 Interrupt Structure
Reset Sources
22
AT43USB355
BUS RESET
RESERVED
GLB SUSP
FRMWUP
EOF2
HEP0
FEP3
FEP2
FEP1
FEP0
RSM
SOF
The AT43USB355 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 RESETN 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 AT43USB355 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
TIMER1 COMPB
TIMER1 COMPA
TIMER1CAPT
TIMER0 OVF
TIMER1 OVF
ADC
USB
SPI STC
RESET
INT1
INT0
Microcontroller
13
12
9
8
7
6
5
4
3
2
1
Interrupt
Logic
2603G–USB–04/06