Datasheet

107
AT8xC51SND1C
4109E–8051–06/03
Table 101. UBYCTX Register
UBYCTX (S:E2h) – USB Endpoint X Byte Count Register (X = EPNUM set in UEPNUM)
Reset Value = 0000 0000b
Table 102. UFNUML Register
UFNUML (S:BAh, Read-only) – USB Frame Number Low Register
Reset Value = 00h
76543210
- BYCT6 BYCT5 BYCT4 BYCT3 BYCT2 BYCT1 BYCT0
Bit
Number
Bit
Mnemonic Description
7-
Reserved
The value read from this bits is always 0. Do not set this bit.
6 - 0 BYCT7:0
Byte Count
Byte count of a received data packet. This Byte count is equal to the number of
data Bytes received after the Data PID.
76543210
FNUM7 FNUM6 FNUM5 FNUM4 FNUM3 FNUM2 FNUM1 FNUM0
Bit
Number
Bit
Mnemonic Description
7 - 0 FNUM7:0
Frame Number
Lower 8 bits of the 11-bit Frame Number.