AT90USB1286-16MU ATMEL [ATMEL Corporation], AT90USB1286-16MU Datasheet - Page 284

• Manufacturer Part Number: AT90USB1286-16MU
• Description: Microcontroller with 64/128K Bytes of ISP Flash and USB Controller
• Manufacturer: ATMEL [ATMEL Corporation]

22.19.2
284
AT90USB64/128
USB device endpoint registers
• Frame Number Lower Flag
Set by hardware. These bits are the 8 LSB of the 11-bits Frame Number information.
• 7-5 - Reserved
The value read from these bits is always 0. Do not set these bits.
• 4 - FNCERR -Frame Number CRC Error Flag
Set by hardware when a corrupted Frame Number in start of frame packet is received.
This bit and the SOFI interrupt are updated at the same time.
• 3-0 - Reserved
The value read from these bits is always 0. Do not set these bits.
• 7-3 - Reserved
The value read from these bits is always 0. Do not set these bits.
• 2-0 - EPNUM2:0 Endpoint Number Bits
Load by software to select the number of the endpoint which shall be accessed by the CPU. See
Section 22.6, page 270 for more details.
EPNUM = 111b is forbidden.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
Bit
Read/W
rite
Initial
Value
7
0
-
R
R
R
7
0
7
0
7
0
-
-
EPRST6
6
0
-
R/W
R
R
6
0
6
0
6
0
-
EPRST5
5
0
-
R/W
R
5
0
R
5
0
5
0
-
FNCERR
EPRST4
R
4
0
R/W
R
4
0
R
4
0
4
0
-
FNUM7:0
EPRST3
R/W
3
0
-
R
3
0
R
3
0
3
0
-
EPRST2
R/W
R/W
2
0
R
2
0
-
2
0
2
0
EPNUM2:0
EPRST1
R/W
R/W
R
1
0
1
0
-
1
0
1
0
EPRST0
R/W
R/W
R
0
0
0
0
0
0
0
0
-
7593A–AVR–02/06
UDFNUML
UDMFN
UENUM
UERST