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CHAPTER 6 USB CONTROLLER
Preliminary User’s Manual S14767EJ1V0UM00
387
6.2.2.11
USB EP4 Control Register (U_EP4CR): 30H
31
16
MAXP4
15
0
7
Reserved
Reserved
30
6
NAK4
NHSK4
EP4EN
SS4
17
18
19
20
RM4
21
Register for setting the operation of and EndPoint4.
If the value in the MAXP field is rewritten during a send or receive operation, the operation of USB Controller may
become unpredictable. Therefore the MAXP can be written to once only, when initial setting is being performed.
Bit
Field
Description
R/W
31
EP4EN
(EndPoint Enable)
If the V
R
4120A RISC processor sets this bit to 1, EndPoint4 is enabled for
transmitting and receiving data from and to USB.
R/W
30-21
Reserved
Reserved for future use
R
20-19
RM4
(Rx Mode)
Bit for setting the send mode.
When this bit is set to 0, sending is performed in SZLP Mode.
When this bit is set to 1, sending is performed in NZLP Mode.
For a detailed explanation of the send modes, see Section 6.5.3.
R/W
18
SS4
(Send Stall)
If the V
R
4120A RISC Processor sets this bit to 1, STALL handshake is
performed at EndPoint4.
R/W
17
NHSK4
(No Handshake)
If the V
R
4120A RISC Processor sets this bit to 1, No Handshake is
performed at EndPoint4.
R/W
16
NAK4
If the V
R
4120A RISC Processor sets this bit to 1, NAK Handshake is
performed at EndPoint4.
R/W
15-7
Reserved
Reserved for future use
R
6-0
MAXP4
(MAX Packet size)
Register that stores the Max Packet Size for EndPoint4. Prior to the start of
a USB transaction, the V
R
4120A RISC Processor must write an appropriate
value into this register.
When this field contains 0, no transaction is performed at EndPoint4.
R/W