AT43USB325E-AU Atmel, AT43USB325E-AU Datasheet - Page 23

• 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

Figure 4-2.
4.5
3355C–USB–4/05
Reset Sources
AT43USB325 Interrupt Structure
BUS RESET
GLB SUSP
FRMWUP
EOF2
HEP0
FEP2
FEP1
FEP0
FEP3
SOF
INTA
INTB
INTC
INTD
RSM
The AT43USB325 has four sources of reset:
• Power-on Reset – The MCU is reset when the supply voltage is below the power-on reset
• External Reset – The MCU is reset when a low level is present on the RESET pin for more
• Watchdog Reset – The MCU is reset when the watchdog timer period expires and the
• USB Reset – The AT43USB325 has a feature to separate the USB and microcontroller
threshold.
than 50 ns.
watchdog is enabled.
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.
– Resets not separated: A USB bus reset will also reset the microcontroller.
Suspend/Resume
USB Interrupt
Flag Register
Register
Enable Register
Suspend/Resume
Interrupt Enable
USB Interrupt
Register
Suspend/Resume
Mask Register
USB Interrupt
Interrupt Mask
Register
TIMER0 OVF
TIMER OVF
COMPB
COMPA
USB
RESET
INT1
INT0
Microcontroller
13
3
8
7
6
5
2
1
Interrupt
Logic
AT43USB325
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