HD6417641 RENESAS [Renesas Technology Corp], HD6417641 Datasheet - Page 820

• Manufacturer Part Number: HD6417641
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 20 USB Function Module
Data Stage (Control-IN): The application first analyzes command data from the host in the setup
stage, and determines the subsequent data stage direction. If the result of command data analysis is
that the data stage is in-transfer, one packet of data to be sent to the host is written to the FIFO. If
there is more data to be sent, this data is written to the FIFO after the data written first has been
sent to the host (USBIFR0/EP0iTS = 1).
The end of the data stage is identified when the host transmits an OUT token and the status stage
is entered.
Note: If the size of the data transmitted by the function is smaller than the data size requested by
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the host, the function indicates the end of the data stage by returning to the host a packet
shorter than the maximum packet size. If the size of the data transmitted by the function is
an integral multiple of the maximum packet size, the function indicates the end of the data
stage by transmitting a zero-length packet.
Data transmission to host
(USBIFR0/EP0i TS = 1)
Set EP0i transmission
IN token reception
to USBTRG/EP0s
in EP0i FIFO?
USB function
complete flag
Valid data
Figure 20.6 Data Stage (Control-IN) Operation
1 written
RDFN?
Yes
Yes
ACK
NACK
NACK
No
No
Interrupt request
data register (USBEPDR0i)
data register (USBEPDR0i)
(USBTRG/EP0i PKTE = 1)
(USBTRG/EP0i PKTE = 1)
Clear EP0i transmission
(USBIFR0/EP0i TS = 0)
Write data to USBEP0i
Write data to USBEP0i
Write 1 to EP0i packet
Write 1 to EP0i packet
From setup stage
complete flag
Application
enable bit
enable bit