Datasheet

Table Of Contents
Section 15 Universal Serial Bus Interface (USB)
Page 594 of 846 REJ09B0140-0900 Rev. 9.00
Sep 16, 2010
H8S/2215 Group
EP3o receive data and status bit reading
As shown in figure 15.35, FIFO are switched on SOF packet reception. FIFOs thus store the
latest data. Accordingly, receive data sent from the host in frame [N] can only be read in frame
[N+1]. In addition, the EP3oTF and EP3oTS status bits of UIFR1 are automatically switched
on with each SOF packet reception; the EP3oTF and EP3oTS status in frame [N] can only be
read in frame [N + 1].
Data (1) Modify
Receive USB
data (1)
[In frame N]
[In frame N + 1]
[In frame N + 2]
Receive USB
data (2)
Receive USB
data (3)
TSTF
EP3o FIFO A
EP3o FIFO B
——
——
Data (1)
Data (2)
Modify
A-side flag update
Data (1) can be read in
frame [N + 1]
TSTF
TSTF
EP3o FIFO A Internal flag (A-side)
UIFR1
EP3o FIFO B
Data (3)
Data (2)
Modify
Data (2) can only be read in
frame [N + 2]
TSTF
TSTF
EP3o FIFO A Internal flag (A-side)
UIFR1
EP3o FIFO B
TSTF
Next frame
Next frame
No change
Internal flag (B-side)
Internal flag (B-side)
Internal flag (A-side) UIFR1
B-side flag update
TSTF Can be read
Can be read
Internal flag (B-side)
Figure 15.35 EP3o Data Reception