atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 305

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

ATmega32U4
Set by hardware when a NAK handshake has been sent in response of a IN request from the
host. This triggers an USB interrupt if NAKINE is sent.
Shall be cleared by software. Setting by software has no effect.
• 5 - RWAL - Read/Write Allowed Flag
Set by hardware to signal:
- for an IN endpoint: the current bank is not full i.e. the firmware can push data into the FIFO,
- for an OUT endpoint: the current bank is not empty, i.e. the firmware can read data from the
FIFO.
The bit is never set if STALLRQ is set, or in case of error.
Cleared by hardware otherwise.
This bit shall not be used for the control endpoint.
• 4 - NAKOUTI - NAK OUT Received Interrupt Flag
Set by hardware when a NAK handshake has been sent in response of a OUT/PING request
from the host. This triggers an USB interrupt if NAKOUTE is sent.
Shall be cleared by software. Setting by software has no effect.
• 3 - RXSTPI - Received SETUP Interrupt Flag
Set by hardware to signal that the current bank contains a new valid SETUP packet . An inter-
rupt (EPINTx) is triggered (if enabled).
Shall be cleared by software to handshake the interrupt. Setting by software has no effect.
This bit is inactive (cleared) if the endpoint is an IN endpoint.
• 2 - RXOUTI / KILLBK - Received OUT Data Interrupt Flag
Set by hardware to signal that the current bank contains a new packet. An interrupt (EPINTx) is
triggered (if enabled).
Shall be cleared by software to handshake the interrupt. Setting by software has no effect.
Kill Bank IN Bit
Set this bit to kill the last written bank.
Cleared by hardware when the bank is killed. Clearing by software has no effect.
See
page 294
for more details on the Abort.
• 1 - STALLEDI - STALLEDI Interrupt Flag
Set by hardware to signal that a STALL handshake has been sent, or that a CRC error has been
detected in a OUT isochronous endpoint.
Shall be cleared by software. Setting by software has no effect.
• 0 - TXINI - Transmitter Ready Interrupt Flag
Set by hardware to signal that the current bank is free and can be filled. An interrupt (EPINTx) is
triggered (if enabled).
Shall be cleared by software to handshake the interrupt. Setting by software has no effect.
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