Figure 15.13 Data Stage Operation (Control-In) - Hitachi H8S/2215 Series Hardware Manual

USB function
IN token reception
1 written
to UTRG0/EP0s
RDFN?
Valid data
in EP0i FIFO?
Data transmission to host
Set EP0i transmission
complete flag
(UIFR0/EP0i TS = 1)
Note: If the size of the data transmitted by the function is smaller than the data size requested by the host,
the function indicates the end of the data stage by returnning 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.

Figure 15.13 Data Stage Operation (Control-In)

No
NACK
Yes
No
NACK
Yes
ACK
Firmware
From setup stage
Write data to USB endpoint
data register 0i (UEDR0i)
Write 1 to EP0i packet
enable bit
(UTRG0/EP0i PKTE = 1)
Clear EP0i transmission
complete flag
(UIFR0/EP0i TS = 0)
Write data to USB endpoint
data register 0i (UEDR0i)
Write 1 to EP0i packet
enable bit
(UTRG0/EP0i PKTE = 1)
Rev. 3.0, 10/02, page 495 of 686