ATMEGA8U2-MU Atmel, ATMEGA8U2-MU Datasheet - Page 206

• Manufacturer Part Number: ATMEGA8U2-MU
• Description: MCU AVR 8K FLASH USB 32-VQFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8U2-MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Processor Series: ATMEGA8x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 1 KB
• Interface Type: SPI, UART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 2
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT, AT90USBKEY, ATEVK525
• Minimum Operating Temperature: - 40 C
• Package: 32QFN EP
• Device Core: AVR
• Family Name: ATmega
• Maximum Speed: 16 MHz
• Operating Supply Voltage: 3.3|5 V
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Converters: -
• Lead Free Status / Rohs Status: Details

21.14.1
21.14.1.1
7799D–AVR–11/10
Example with 1 IN data bank
Detailed description
Example with 2 IN data banks
FIFOCON
FIFOCON
TXINI
TXINI
Abort
SW
SW
write data from CPU
write data from CPU
The RWAL bit always reflects the state of the current bank. This bit is set if the firmware can
write data to the bank, and cleared by hardware when the bank is full.
The data are written by the CPU, following the next flow:
If the endpoint uses 2 banks, the second one can be read by the HOST while the current is
being written by the CPU. Then, when the CPU clears FIFOCON, the next bank may be already
ready (free) and TXINI is set immediately.
An “abort” stage can be produced by the host in some situations:
• When the bank is empty, an endpoint interrupt (EPINTx) is triggered, if enabled (TXINE set)
• The CPU acknowledges the interrupt by clearing TXINI,
• The CPU can write the data into the current bank (write in UEDATX),
• The CPU can free the bank by clearing FIFOCON when all the data are written, that is:
• after “N” write into UEDATX
• as soon as RWAL is cleared by hardware.
NAK
BANK 0
and TXINI is set. The CPU can also poll TXINI or FIFOCON, depending the software
architecture choice,
BANK 0
SW
SW
IN
IN
SW
write data from CPU
BANK 1
(bank 0)
(bank 0)
DATA
DATA
SW
HW
HW
ACK
ACK
ATmega8U2/16U2/32U2
SW
SW
write data from CPU
write data from CPU
IN
BANK 0
BANK0
(bank 1)
DATA
SW
IN
ACK
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