Datasheet

Section 16 USB Function Module (USB)
R01UH0309EJ0500 Rev. 5.00 Page 981 of 1408
Sep 24, 2012
H8S/2456, H8S/2456R, H8S/2454 Group
• 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 16.2.
1. Endpoint number 0 and endpoint FIFO number 0 must have one-on-one relationship.
2. The maximum packet size for endpoint FIFO number 0 is limited to 16 bytes.
3. For endpoint FIFO number 0, only the maximum packet size can be specified and the data for
the rest should be all 0.
4. The maximum packet size for endpoint FIFO numbers 1 and 2 is limited to 64 bytes.
5. Only the bulk transfer method and out transfer direction can be specified for endpoint FIFO
numbers 1.
6. Only the bulk transfer method and in transfer direction can be specified for endpoint FIFO
numbers 2.
7. The maximum packet size for endpoint FIFO numbers 3 is limited to 16 bytes.
8. Only the interrupt transfer method and in transfer direction can be specified for endpoint FIFO
numbers 3.
9. The maximum number of endpoint information settings is four.
10. Four endpoint information settings should be made.
11. Write 0 to the endpoints not in use.
Table 16.2 shows the limitations for the maximum packet size, the transfer method, and the
transfer direction.