AT83C51SND1C_03 ATMEL [ATMEL Corporation], AT83C51SND1C_03 Datasheet - Page 83

• Manufacturer Part Number: AT83C51SND1C_03
• Description: Single-Chip Flash Microcontroller with MP3 Decoder and Human Interface
• Manufacturer: ATMEL [ATMEL Corporation]

Function Interface Unit (UFI)
Figure 58. UFI Block Diagram
Figure 59. USB Typical Transaction Load
4109E–8051–06/03
IN Transactions:
OUT Transactions:
HOST
HOST
12 MHz DPLL
To/From SIE
C51
C51
UFI
UFI
OUT
IN
NACK
DATA0 (n Bytes)
Endpoint FIFO Write
Endpoint Control
The Function Interface Unit provides the interface between the AT8xC51SND1C and
the SIE. It manages transactions at the packet level with minimal intervention from the
device firmware, which reads and writes the endpoint FIFOs.
Figure 59 shows typical USB IN and OUT transactions reporting the split in the hard-
ware (UFI) and software (C51) load.
USB side
Transfer
Control
FSM
ACK
IN
C51 interrupt
Asynchronous Information
Endpoint FIFO read (n Bytes)
Endpoint 2
Endpoint 1
Endpoint 0
DATA1
OUT
DATA1
IN
Endpoint Control
USBADDR
UEPCONX
UEPDATX
UEPSTAX
NACK
C51 side
USBCON
UEPNUM
UFNUMH
UFNUML
UEPRST
UBYCTX
USBINT
USBIEN
UEPINT
UEPIEN
DATA1
OUT
ACK
AT8xC51SND1C
To/From C51 Core
C51 interrupt
DATA1
Endpoint FIFO write
ACK
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