NEC Network Controller uPD98502 - Manual (Page 318)

CHAPTER 6 USB CONTROLLER
318 Preliminary User’s Manual S15543EJ1V0UM
6.2.6 U_GSR2 (USB General Status Register 2)
This register indicates the current status of USB Controller. Reading this register clears all bits in this register.
Bits Field R/W Default Description
31:21 Reserved R 0 Reserved for future use
21 FW RC 0 Frame Number Written:
This bit is set to a ‘1’ when Frame Number is written to USB Frame
Number/Version Register (04H).
20 IFN RC 0 Incorrect Frame Number:
This bit is set to a ‘1’ when USB Controller receives a SOF packet with
Incorrect Frame Number, or with CRC/Bit Stuff error.
19 IEA RC 0 Incorrect EndPoint Access:
This bit is set to a ‘1’ when USB Controller received an IN or OUT Token with
Incorrect EndPoint Number.
18 URSM RC 0 USB Resume:
This bit is set to a ‘1’ when USB Controller has received a Resume Signaling
from the Host PC.
17 URST RC 0 USB Reset:
This bit is set to a ‘1’ when USB Controller has received a Reset Signaling
from the Host PC.
16 USPD RC 0 USB Suspend:
This bit is set to a ‘1’ when USB Controller detects that USB enters Suspend
state.
15:8 Reserved R 0 Reserved for future use
7 EP2OS RC 0 Over Size on EndPoint2:
This bit is set to a ‘1’ when the received data size is over Max Packet Size on
EP2.
6 EP2ED RC 0 Extra Data on EndPoint2:
This bit is set to a ‘1’ when an extra data packet is detected on Isochronous
EndPoint (EP2). In the case that EP2EN bit in U_EP2CR is set to a ‘0’, this
bit will not be set even if the USB Controller detects an extra data on EP2.
5 EP2ND RC 0 Isochronous Data Corrupted on EndPoint2:
Bit that indicates that Isochronous data is corrupted on EP2. In the case that
EP2EN bit in U_EP2CR is set to a ‘0’, this bit will not be set even if the USB
Controller detects data corruption on EP2.
4 EP1NT RC 0 No Token on EndPoint1:
This bit is set to a ‘1’ when IN Token packet does not come on EP1 between
two SOFs. In the case that EP1EN bit in U_EP1CR is set to a ‘0’, this bit will
not be set even if the USB Controller detects no token packet on EP1.
3 EP1ET RC 0 Extra Token on EndPoint1:
This bit is set to a ‘1’ when two IN Token packets are received on EP1
between two SOFs. In the case that EP1EN bit in U_EP1CR is set to a ‘0’,
this bit will not be set even if the USB Controller detects an extra token
packet on EP1.
2 EP1ND RC 0 No Data on EndPoint1:
This bit is set to a ‘1’ when IN Token packet comes but any data is not ready
on EP1. In the case that EP1EN bit in U_EP1CR is set to a ‘0’, this bit will not
be set even if the USB Controller detects no data condition on EP1.
1 ES RC 0 Extra SOF:
This bit is set to a ‘1’ when extra SOF packet is detected.
0 SL RC 0 SOF Loss:
This bit is set to a ‘1’ when USB Controller doesn’t receive any SOF packet.