CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
Preliminary User’s Manual U19014EJ1V0UD
323
Figure 12-2. Operation of UF0E0R Register
Status of UF0E0R
register
Normal
completion
of reception
Normal
completion
of reception
Abnormal
reception
FIFO
hard-
ware
clear
EP0NKR bit of
UF0E0N register
EP0R
bit of
UF0EPS0
register
E0ODT
bit of
UF0IS1
register
Hardware clear
Hardware clear
Reading
FIFO
starts
Reading
FIFO
completed
Hardware clear
(2) UF0 EP0 length register (UF0E0L)
The UF0E0L register stores the data length held by the UF0E0R register.
This register is read-only, in 8-bit units. A write access to this register is ignored.
The UF0E0L register always updates the length of the received data while it is receiving data. If the final
transfer is abnormal reception, the UF0E0L register is cleared to 0 and the interrupt request is not generated.
The interrupt request is generated only when the reception is normal, and the FW can read as many data from
the UF0E0R register as the value read from the UF0E0L register. The value of the UF0E0L register is
decremented each time the UF0E0R register has been read.
E0L7
UF0E0L
E0L6
5
E0L5
E0L4
3
E0L3
2
E0L2
1
E0L1
E0L0
Address
FF76H
After reset
00H
0
4
6
7
Bit position
Bit name
Function
7 to 0
E0L7 to E0L0
These bits store the data length held by the UF0E0R register.
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