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CHAPTER 6 USB CONTROLLER
Preliminary User’s Manual S14767EJ1V0UM00
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(3) EndPoint2, EndPoint4, assemble mode
The processing in EndPoint2, EndPoint4 receive Assemble mode is explained below.
Figure 6-18. EndPoint2, EndPoint4 Receive Assemble Mode
D0
μ
PD98501
Buffer
Directory
D1
D2
D1
D2
D2
Rx Indication
D0
D0
D1
D3
D3
In this mode USB Controller issues Rx indication after receiving one data segment.
In other word, after USB Controller writes the Short packet or Zero-Length Packet received from USB to buffer in
system memory, USB Controller renewing Size field, Last bit in last Buffer Descriptor and issues Rx indication.
(4) EndPoint2, EndPoint4, separate mode
The processing in EndPoint2, EndPoint4 receive separate mode is explained below.
Figure 6-19. EndPoint2, EndPoint4 Receive Separate Mode
D0
μ
PD98501
Buffer
Directory
D1
D2
D1
D2
D2
Rx Indication
Rx Indication
Rx Indication
Rx Indication
D0
D0
D1
D2
In this mode, after USB Controller receives USB packet and stores the data in receive buffer, it issues Rx indication
when buffer was full. If buffer was full in the middle of USB packets, in that time it issues indication. After that,
processing of storing the USB packet to next buffer continues.
It does not execute to renew Size field, Last bit in Buffer Descriptor.
Caution
If you want to guarantee the behavior of Isochronous EndPoint as well as possible, Rx Normal
Mode and software processing is recommended. Rx Assemble mode and Separate Mode is not
fit to Isochronous EndPoint.