CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
Preliminary User’s Manual U19014EJ1V0UD
286
(2/2)
Bit position
Bit name
Function
0
BKI1NK
This bit controls NAK to Endpoint1 (bulk 1 transfer (IN)).
1: Do not transmit NAK.
0: Transmit NAK (default value).
This bit is cleared to 0 only when the FIFO connected to the SIE side of the UF0BI1
register (64-byte FIFO of bank configuration) cannot receive data. It is set to 1 when a
toggle operation is performed (the data of the UF0BI1 register is retained until
transmission has been correctly completed). The bank is changed (toggle operation)
when the following conditions are satisfied.
•
Data is correctly written to the FIFO connected to the CPU bus side (writing has
been completed and the FIFO is full or the UF0DEND register is set).
•
The value of the FIFO counter connected to the SIE side is 0.
This bit is automatically set to 1 and data transmission is started when the FIFO on the
CPU side becomes full and a FIFO toggle operation is performed as a result of writing
data to the FIFO. To send a short packet that does not make the FIFO on the CPU side
full, set the BKI1DED bit to 1 after completing writing data. When the BKI1DED bit is set
to 1, a toggle operation is performed and at the same time, this bit is automatically set to
1. This bit is also cleared to 0 as soon as the UF0BI1 register has been cleared.
electronic components distributor
