Datasheet

285
7766F–AVR–11/10
ATmega16/32U4
• 7-3 - Reserved
The value read from these bits is always 0. Do not set these bits.
• 2 - CTRLDIR - Control Direction (Flag, and bit for debug purpose)
Set by hardware after a SETUP packet, and gives the direction of the following packet:
- 1 for IN endpoint
- 0 for OUT endpoint.
Can not be set or cleared by software.
• 1-0 - CURRBK1:0 - Current Bank (all endpoints except Control endpoint) Flag
Set by hardware to indicate the number of the current bank:
00b Bank0
01b Bank1
1xb Reserved.
Can not be set or cleared by software.
• 7 - FIFOCON - FIFO Control Bit
For OUT and SETUP Endpoint:
Set by hardware when a new OUT message is stored in the current bank, at the same time than
RXOUT or RXSTP.
Clear to free the current bank and to switch to the following bank. Setting by software has no
effect.
For IN Endpoint:
Set by hardware when the current bank is free, at the same time than TXIN.
Clear to send the FIFO data and to switch the bank. Setting by software has no effect.
• 6 - NAKINI - NAK IN Received Interrupt Flag
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.
Bit 76543 2 10
- - - - - CTRLDIR CURRBK1:0 UESTA1X
Read/Write R R R R R R R R
Initial Value 0 0 0 0 0 0 0 0
Bit 76543210
FIFOCON NAKINI RWAL NAKOUTI RXSTPI RXOUTI STALLEDI TXINI UEINTX
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value00000000