NEC Network Controller uPD98502 - Manual (Page 361)

CHAPTER 6 USB CONTROLLER
Preliminary User’s Manual S15543EJ1V0UM 361
Figure 6-25. Example of Buffers Including Corrupted Data
B uffer des criptor
B uffer des criptor
B uffer des criptor
V alid
D ata
V alid
D ata
V alid
D ata
V alid
D ata
Link pointe r
B uffer des criptor
V alid
B uffer des c.(L=1)
C orrupted
D ata
C orrupted
D ata
B uffer des criptor
Link pointe r
V alid
D ata
B uffer D irectory
V alid
C orrupted
D ata
M ax P ack et S ize
M ax P ack et S ize
6.6.9 Rx FIFO overrun
On Isochronous Rx EndPoint (EP2), if data reading from Rx FIFO is delayed by some problem, Rx FIFO Overrun
will occur.
In the case of corruption, action of USB Controller varies according to Rx Mode.
(a) Rx normal mode
USB Controller sets EP2FO (EndPoint2 No Data) bit (Bit 9) in USB General Status Register 2.
USB Controller writes the Rx indications which indicates that EP2 FIFO Overrun has occurred.
USB Controller doesn’t write any dummy data to Data Buffer on system memory.