![](http://datasheet.mmic.net.cn/380000/-PD78F9801_datasheet_16745018/-PD78F9801_114.png)
CHAPTER 8 USB FUNCTION
114
Figure 8-11. Format of Data/Handshake Packet Receive Mode Register
Symbol
6
7
5
4
3
<2>
<1>
<0>
0
0
0
0
0
RESMOD
DINTEN
DWRMSK
RESMOD
USB reset signal detection mode setting
0
1
FF66H
Address
URXMOD
After reset
00H
R/W
R/W
Rejects USB reset signal less than 3.0 s SE0 (Single-ended0) period.
Detects transition from J state to SE0 as USB reset signals.
DINTEN
Data/handshake packet receive interrupt enable flag
0
1
Does not generate data/handshake packet receive interrupt request (INTUSBRD).
Generates data/handshake packet receive interrupt request (INTUSBRD).
DWRMSK
Data/handshake packet write disable setting
0
1
Enables write operation to all addresses in data/handshake packet receive buffer.
Disables write operation to addresss greater than 11H in data/handshake packet receive buffer.
Note 1
Note 2
Notes 1.
Do not set data immediately before entering bus suspend mode. Clear immediately when returning
from the bus suspend mode.
If the bus is disturbed by a noise, the noise is detected as a USB reset signal. Confirm whether USB
reset signal is input by checking the URESRX flag (bit 4 of the USB receive status register (RXSTAT))
more than once by software.
2.
(3)
Packet receive status register (RXSTAT)
This register indicates the receive status of each packet.
Bits 0 to 2 (TOSTAT, DASTAT, and HSSTAT) are flags that indicate that a token packet, data packet, or
handshake packet is currently being received. These flags are set upon detection of a packet ID with an ID
detection buffer, and cleared upon reception of EOP.
Bits 3 to 6 (EOPRX, URESRX, SE0RX, RESMRX) are flags that detect bus status transition. These flags
are set immediately after each bus transition is detected. These flags are cleared by software.
Bit 7 (UWDERR) is set if an inadvertent program loop is detected in the USB timer. The flags are cleared
by software. The UWDERR cannot be set by software. An inadvertent program loop in the USB timer
means that EOP cannot be detected in a packet received from the host, or that noise on a bus was detected
as a bus status transition.
The RXSTAT is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets the RXSTAT to 00H.