upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 284

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

284
(2) UF0 EP0NAKALL register (UF0E0NA)
UF0E0NA
Bit position
This register controls NAK to all the requests of Endpoint0. It is also valid for automatically executed requests.
This register can be read or written in 8-bit units.
0
7
0
EP0NKA
Bit name
6
0
CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
This bit controls NAK to a transaction other than a SETUP transaction to Endpoint0
(including an automatically executed request). This bit is manipulated by FW.
This register is used to prevent a conflict between a write access by FW and a read
access from SIE when the data used for an automatically executed request is to be
changed. It postpones reflecting a write access on this bit from FW while an access
from SIE is being made. Before rewriting the request data register from FW, confirm that
this bit has been correctly set to 1.
Setting this bit to 1 is reflected only in the following cases.
Clearing this bit to 0 is reflected immediately, except while an IN token is being received
and a NAK response is being made.
Setting the EP0NKA bit to 1 is reflected in the above four cases during Endpoint0
transfer, but it is reflected immediately after data has been written to the bit while
Endpoint0 is transferring no data.
5
0
1: Transmit NAK.
0: Do not transmit NAK (default value).
• Immediately after USBF has been reset and a SETUP token has never been
• Immediately after reception of Bus Reset and a SETUP token has never been
• PID of a SETUP token has been detected
• The stage has been changed to the status stage
received
received
Preliminary User’s Manual U19014EJ1V0UD
4
0
3
0
2
0
Function
1
0
EP0NKA
0
Address
FF61H
After reset
00H