Datasheet

129
4341H–MP3–10/07
AT8xC51SND2C/MP3B
Table 16-13. UBYCTX Register
UBYCTX (S:E2h) – USB Endpoint X Byte Count Register (X = EPNUM set in UEPNUM)
Reset Value = 0000 0000b
Table 16-14. UFNUML Register
UFNUML (S:BAh, Read-only) – USB Frame Number Low Register
Reset Value = 00h
7 6 5 4 3 2 1 0
- 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.
7 6 5 4 3 2 1 0
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.