NEC Network Controller uPD98502 - Manual (Page 322)

CHAPTER 6 USB CONTROLLER
322 Preliminary User’s Manual S15543EJ1V0UM
6.2.11 U_EP3CR (USB EP3 Control Register)
This register is used for setting the operation of EndPoint3.
If the value in the MAXP field is rewritten during transmitting operation, the operation of USB Controller may
become unpredictable. Therefore, the MAXP can be written only when initial setting is being performed.
Bits Field R/W Default Description
31 EP3EN R/W 0 EndPoint Enable:
When the V R 4120A sets this bit to a ‘1’, EndPoint3 is enabled for transmit
data.
30:20 Reserved R/W 0 Reserved for future use. Writes ‘0’s.
19 TM3 R/W 0 Tx Mode:
Bit for setting the transmit mode.
When this bit is set to a ‘0’, transmitting is performed in SZLP Mode.
When this bit is set to a ‘1’, transmitting is performed in NZLP Mode.
For a detailed explanation of the transmit modes, see Section 6.5.3.
18 SS3 R/W 0 Transmit Stall:
When the V R 4120A sets this bit to a ‘1’, a STALL packet is sent from
EndPoint3.
17 Reserved R/W 0 Reserved for future use. Writes ‘0’s.
16 NAK3 R/W 0 When the V
R
4120A sets this bit to a ‘1’, a NAK packet is sent from
EndPoint3.
15:7 Reserved R/W 0 Reserved for future use. Writes ‘0’s.
6:0 MAXP3 R/W 0 MAX Packet size:
The Max Packet Size for EndPoint3. Prior to the start of a USB transaction,
the V R 4120A must write an appropriate value into this register.