ATmega32U2 Atmel Corporation, ATmega32U2 Datasheet - Page 199

• Manufacturer Part Number: ATmega32U2
• Manufacturer: Atmel Corporation

Specifications of ATmega32U2

• Flash (kbytes): 32 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 22
• Ext Interrupts: 20
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 1
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 5
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

21.7
7799D–AVR–11/10
Address Setup
Figure 21-2. Endpoint activation flow:
As long as the endpoint is not correctly configured (CFGOK cleared), the hardware does not
acknowledge the packets sent by the host.
CFGOK will not be set if the Endpoint size parameter is bigger than the DPRAM size.
A clear of EPEN acts as an endpoint reset (see
It also performs the next operation:
S e e
allocation/reorganization.
The USB device address is set up according to the USB protocol:
ADDEN and UADD shall not be written at the same time.
• The configuration of the endpoint is kept (EPSIZE, EPBK, ALLOC kept)
• It resets the data toggle field.
• The DPRAM memory associated to the endpoint is still reserved.
• the USB device, after power-up, responds at address 0
• the host sends a SETUP command (SET_ADDRESS(addr)),
• the firmware records that address in UADD, but keep ADDEN cleared,
• the USB device sends an IN command of 0 bytes (IN 0 Zero Length Packet) to acknowledge
• then, the firmware may enable the USB device address by setting ADDEN. The only
the transaction,
accepted address by the controller is the one stored in UADD.
“ M e m o r y m a n a g e m e n t ” o n p a g e 1 9 2
Endpoint activated
Yes
UECFG0X
UECFG1X
CFGOK=1
Activation
Endpoint
EPEN=1
UENUM
EPNUM=x
EPTYPE
EPSIZE
ALLOC
EPDIR
EPBK
...
No
ERROR
“Endpoint reset” on page 197
ATmega8U2/16U2/32U2
f o r m o r e d e t a i l s a b o u t t h e m e m o r y
Select the endpoint
Activate the endpoint
Configure:
Configure:
Allocation and reorganization of
the memory is made on-the-fly
Test the correct endpoint
configuration
- the endpoint direction
- the endpoint type
- the Not Yet Disable feature
- the endpoint size
- the bank parametrization
for more details).
199