Specification
NET2272 USB Peripheral Controller
______________________________________________________________________________
NetChip Technology, Inc., 2003
Patent Pending
335 Pioneer Way, Mountain View, California 94041
TEL (650) 526-1490
FAX (650) 526-1494
http://www.netchip.com
Rev 1.2, October 15, 2003
74
8.6.16 (Address 2Ch: EP_BUFF_STATES) Endpoint Buffer States
Bits
Description
Read
Write
Default
Value
7:4
Reserved.
Yes
No
0
3:2
Buffer B State. This field provides the current state of the endpoint buffer B.
Value
State
00
Buff_Free; buffer is empty, free to assign
01
Buff_Valid; buffer has valid packet, waiting to move to local or USB side
10
Buff_Lcl; buffer is assigned to the local side
11
Buff_Usb; buffer is assigned to the USB side
Yes
No
--
1:0
Buffer A State. This field provides the current state of the endpoint buffer A.
Value
State
00
Buff_Free; buffer is empty, free to assign
01
Buff_Valid; buffer has valid packet, waiting to move to local or USB side
10
Buff_Lcl; buffer is assigned to the local side
11
Buff_Usb; buffer is assigned to the USB side
Yes
No
--
IN packets move: Lcl -> Valid -> Usb -> Free
OUT packets move: Usb -> Valid -> Lcl -> Free
If an endpoint is double-buffered, the buffers are never in the same state. If an endpoint is single-buffered, the
unused (B) buffer is locked to the Buff_Free state.
8.7
Register Changes from Net2270
•
Add Virtualized Endpoint Interrupt Enable to IRQENB0[4].
•
Add Virtualized Endpoint Interrupt Status to IRQSTAT0[4].
•
Add new LOCCTL1 register. Add DMA Mode bit to LOCCTL1[1:0].
•
Add Virtual Endpoint Enable bit to USBCTL[4].
•
Add Virtual OUT Interrupt 0 register (VIRTOUT0).
•
Add Virtual OUT Interrupt 1 register (VIRTOUT1).
•
Add Virtual IN Interrupt 0 register (VIRTIN0).
•
Add Virtual IN Interrupt 1 register (VIRTIN1).
•
Add Local OUT ZLP status bit to EP_STAT1[6].
•
Add new EP_HBW register.
•
Add new EP_BUFF_STATES register.
•
Remove Force Bi-directional to Inputs bit from USBDIAG register.
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