Datasheet

Section 22 USB Function Module (USB)
Rev. 2.00 Aug. 20, 2008 Page 856 of 1198
REJ09B0403-0200
• EPIR04
Bit Bit Name
Initial
Value
R/W Description
7 to 0 D7 to D0 Undefined W Endpoint FIFO Number
[Possible setting range]
0 to 3
The endpoint number is the endpoint number the USB host uses. The endpoint FIFO number
corresponds to the endpoint number described in this manual. Thus data transfer between the USB
host and the endpoint FIFO can be enabled by putting the endpoint number and the endpoint FIFO
number in one-to-one correspondence. Note that the setting value is subject to a limitation
described below.
Since each endpoint FIFO number is optimized by the exclusive software that corresponds to the
transfer system, direction, and the maximum packet size, make sure to set the endpoint FIFO
number to the data described in table 22.2.
1. The endpoint FIFO number 1 cannot designate other than the maximum packed size of 8 bytes,
control transfer method, and out transfer direction.
2. The endpoint number 0 and the endpoint FIFO number must have one-on one relationship.
3. The maximum packet size for the endpoint FIFO number 0 is 8 bytes only.
4. The endpoint FIFO number 0 can specify only the maximum packet size and the data for the
rest should be all 0.
5. The maximum packet size for the endpoint FIFO numbers 1 and 2 is limited to 64 bytes.
6. The maximum packet size for the endpoint FIFO numbers 3 is limited to 8 bytes.
7. The maximum number of endpoint information setting is ten.
8. Up to ten endpoint information setting should be made.
9. Write 0 to the endpoints not in use.
Table 22.2 shows the example of limitations for the maximum packet size, the transfer method,
and the transfer direction.
Table 22.2 Example of Limitations for Setting Values
Endpoint FIFO Number Maximum Packet Size Transfer Method Transfer Direction
0 8 bytes Control 
1 64 bytes Bulk Out
2 64 bytes Bulk In
3 8 bytes Interrupt In