AT85C51SND3Bx
Bit
Bit
Number
Mnemonic Description
Endpoint Bank Bits
Set this field according to the endpoint size:
00b: Single bank
3-2
EPBK1:0
01b: Double bank
1xb: Reserved. Do not use this configuration.
Endpoint Allocation Bit
Set this bit to allocate the endpoint memory.
Clear to free the endpoint memory.
See Section “Endpoint Activation” for more details.
1
0
ALLOC
-
Reserved
The value read from these bits is always 0. Do not set these bits.
Reset Value = 0000 0000b
Table 124. UESTA0X Register
UESTA0X (1.CEh) – USB Endpoint Status 0 Register
7
6
5
4
3
2
1
0
CFGOK
OVERFI
UNDERFI
ZLPSEEN
DTSEQ1
DTSEQ0 NBUSYBK1 NBUSYBK0
Bit
Bit
Number
Mnemonic Description
Configuration Status Flag
Set by hardware when the endpoint X size parameter (EPSIZE) and the bank
parametrization (EPBK) are correct compared to the max FIFO capacity and the
max number of allowed bank. This bit is updated when the bit ALLOC is set.
If this bit is cleared, the user should reprogram the UECFG1X register with
correct EPSIZE and EPBK values.
7
6
CFGOK
OVERFI
Overflow Error Interrupt Flag
Set by hardware when an overflow error occurs in an isochronous endpoint. An
interrupt (EPINTx) is triggered (if enabled).
See Section “Isochronous Mode” for more details.
Shall be cleared by software. Setting by software has no effect.
Flow Error Interrupt Flag
Set by hardware when an underflow error occurs in an isochronous endpoint. An
interrupt (EPINTx) is triggered (if enabled).
See Section “Isochronous Mode” for more details.
5
4
UNDERFI
ZLPSEEN
Shall be cleared by software. Setting by software has no effect.
Zero Length Packet Seen (bit / Flag)
Set by hardware, as soon as a ZLP has been filtered during a transfer.
Shall be cleared by the software. Setting by software has no effect.
Data Toggle Sequencing Flag
Set by hardware to indicate the PID data of the current bank:
00b: Data0
01b: Data1
3-2
DTSEQ1:0
1xb: Reserved.
For OUT transfer, this value indicates the last data toggle received on the current
bank.
For IN transfer, it indicates the Toggle that will be used for the next packet to be
sent. This is not relative to the current bank.
121
7632A–MP3–03/06
ATMEL [ ATMEL ]
