CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
Preliminary User’s Manual U19014EJ1V0UD
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(14) UF0 INT status 3 register (UF0IS3)
This register indicates the interrupt source. If the contents of this register are changed, the INTUSB1B signal
becomes active.
This register is read-only, in 8-bit units.
If an interrupt request (INTUSB1B) is generated from USBF, the FW must read this register to identify the
interrupt source.
Each bit of this register is forcibly cleared to 0 when 0 is written to the corresponding bit of the UF0IC3 register.
The related bits are invalid if each endpoint is not supported by the setting of the UF0E2IM register and the
current setting of the interface.
UF0IS3
BKO1DT
5
0
3
BKO1FL
2
BKO1NL
1
BKO1NAK
Address
FF2AH
After reset
00H
0
4
0
6
0
7
0
Bit position
Bit name
Function
3
BKO1FL
This bit indicates that data has been correctly received in the UF0BO1 register (Endpoint
2) and that both the FIFOs of the CPU and SIE hold the data.
1: Received data is in both the FIFOs of the UF0BO1 register (interrupt request is
generated).
0: Received data is not in the FIFO on the SIE side of the UF0BO1 register (default
value).
If data is held in both the FIFOs of the CPU and SIE, this bit is automatically set to 1 by
hardware. This bit is automatically cleared to 0 by hardware when the FIFO is toggled.
2
BKO1NL
This bit indicates that a Null packet (packet with a length of 0) has been received in the
UF0BO1 register (Endpoint 2).
1: Null packet is received (interrupt request is generated).
0: Null packet is not received (default value).
This bit is set to 1 immediately after reception of a Null packet when the FIFO is empty.
This bit is set to 1 when the FIFO on the CPU side has been completely read if data is in
that FIFO.
1
BKO1NAK
This bit indicates that an OUT token has been received to the UF0BO1 register
(Endpoint 2) and that NAK has been returned.
1: OUT token is received and NAK is transmitted (interrupt request is generated).
0: OUT token is not received (default value).
0
BKO1DT
This bit indicates that data has been correctly received in the UF0BO1 register (Endpoint
2).
1: Reception has been completed correctly (interrupt request is generated).
0: Reception has not been completed (default value).
This bit is automatically set to 1 by hardware when data has been correctly received and
the FIFO has been toggled. At the same time, the corresponding bit of the UF0EPS0
register is also set to 1. This bit is not set to 1 when the data is a Null packet. This bit is
automatically cleared to 0 by hardware when the value of the UF0BO1L register
becomes 0 as a result of reading the UF0BO1 register by FW.
This bit is automatically cleared to 0 when all the contents of the FIFO on the CPU side
have been read. However, the interrupt request is not cleared if data is in the FIFO on
the SIE side at this time, and the INTUSB1B signal does not become inactive. The
signal is kept active if data is successively received.
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