Datasheet

301
7593L–AVR–09/12
AT90USB64/128
• 7 - FIFOCON - FIFO Control
For OUT and SETUP Pipe:
Set by hardware when the current bank is free, at the same time than TXOUT or TXSTP.
Clear to send the FIFO data and to switch the bank. Setting by software has no effect.
For IN Pipe:
Set by hardware when a new IN message is stored in the current bank, at the same time than
RXIN.
Clear to free the current bank and to switch to the following bank. Setting by software has no
effect.
• 6 - NAKEDI - NAK Handshake received
Set by hardware when a NAK has been received on the current bank of the Pipe. This triggers
an interrupt if the NAKEDE bit is set in the UPIENX register.
Shall be clear to handshake the interrupt. Setting by software has no effect.
• 5 - RWAL - Read/Write Allowed
OUT Pipe:
Set by hardware when the firmware can write a new data into the Pipe FIFO.
Cleared by hardware when the current Pipe FIFO is full.
IN Pipe:
Set by hardware when the firmware can read a new data into the Pipe FIFO.
Cleared by hardware when the current Pipe FIFO is empty.
This bit is also cleared by hardware when the RXSTALL or the PERR bit is set
• 4 - PERRI -PIPE Error
Set by hardware when an error occurs on the current bank of the Pipe. This triggers an interrupt
if the PERRE bit is set in the UPIENX register. Refers to the UPERRX register to determine the
source of the error.
Automatically cleared by hardware when the error source bit is cleared.
• 3 - TXSTPI - SETUP Bank ready
Set by hardware when the current SETUP bank is free and can be filled. This triggers an inter-
rupt if the TXSTPE bit is set in the UPIENX register.
Shall be cleared to handshake the interrupt. Setting by softw
are has no effect.
• 2 - TXOUTI -OUT Bank ready
Set by hardware when the current OUT bank is free and can be filled. This triggers an interrupt if
the TXOUTE bit is set in the UPIENX register.
Shall be cleared to handshake the interrupt. Setting by software has no effect.
Bit 765432 1 0
FIFOCON NAKEDI RWAL PERRI TXSTPI TXOUTI RXSTALLI RXINI UPINTX
Read/write RW RW RW RW RW RW RW RW
Initial value 0 0 0 0 0 0 0 0