CHAPTER 12 USB FUNCTION CONTROLLER (USBF)
Preliminary User’s Manual U19014EJ1V0UD
318
(33) UF0 active alternative setting register (UF0AAS)
This register specifies a link between the Interface number and Alternative Setting.
This register can be read or written in 8-bit units.
USBF of the
µ
PD78F0730 can set a five-series Alternative Setting (Alternate Setting 0, 1, 2, 3, and 4 can be
defined) and a two-series Alternative Setting (Alternative Setting 0 and 1 can be defined) for one Interface.
ALT2
UF0AAS
IFAL21
5
IFAL20
ALT2EN
3
ALT5
2
IFAL51
1
IFAL50
ALT5EN
Address
FF71H
After reset
00H
0
4
6
7
Bit position
Bit name
Function
7, 3
ALTn
These bits specify whether an n-series Alternative Setting is linked with Interface 0.
When these bits are set to 1, the setting of the IFALn1 and IFALn0 bits is invalid.
1: Link n-series Alternative Setting with Interface 0.
0: Do not link n-series Alternative Setting with Interface 0 (default value).
These bits specify the Interface number to be linked with the n-series Alternative Setting.
If the linked Interface number is outside the range specified by the UF0AIFN register, the
n-series Alternative Setting is invalid (ALTnEN bit = 0).
IFALn1
IFALn0
Interface number to be linked
1
1
Links Interface 4.
1
0
Links Interface 3.
0
1
Links Interface 2.
0
0
Links Interface 1.
6, 5,
2, 1
IFALn1,
IFALn0
Do not link a five-series Alternative Setting and a two-series Alternative Setting with the
same Interface number.
4, 0
ALTnEN
These bits validate the n-series Alternative Setting. Unless these bits are set to 1, the
setting of the ALTn, IFALn1, and IFALn0 bits is invalid.
1: Validate the n-series Alternative Setting.
0: Do not validate the n-series Alternative Setting (default value).
Remark
n = 2, 5
For example, when the UF0AIFN register is set to 82H and the UF0AAS register is set to 15H, Interfaces 0, 1,
2, and 3 are valid. Interfaces 0 and 2 support only Alternative Setting 0. Interface 1 supports Alternative
Setting 0 and 1, and Interface 3 supports Alternative Setting 0, 1, 2, 3, and 4. With this setting, requests
GET_INTERFACE wIndex = 0/1/2/3, SET_INTERFACE wValue = 0 & wIndex = 0/2, SET_INTERFACE wValue
= 0/1 & wIndex = 1, and SET_INTERFACE wValue = 0/1/2/3/4 & wIndex = 3 are automatically responded to,
and a STALL response is made to the other GET/SET_INTERFACE requests.
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