Block Diagram Of Usb Function - NEC switch User Manual

USB receiver
enable register
(USBMOD)
Remote wakeup
control register
(REMWUP)
EOP generation/detection
USBDP Resume & reset
detection control
SYNC detection/
USBDM
USB clock generator
f
X
USB timer
(7-bit counter)
USB timer start
reservation control
register (USBTCL)
Notes 1. Data/handshake packet receive byte number counter (DRXCON), data packet transmit byte number
counter 0, 1 (DTXCO0, DTXCO1)
2. Token address compare register (ADRCMP), token PID compare register (TIDCMP), data/handshake
PID compare register (DIDCMP)
3. Token packet receive result store register (TRXRSL), data/handshake packet receive result store
register (DRXRSL)
4. See Figure 8-3 for USB timer configuration.
CHAPTER 8 USB FUNCTION
Figure 8-2. Block Diagram of USB Function
Internal bus
Data/handshake
packet receive mode
register (URXMOD)
• Handshake packet
• SYNC packet
NRZI
encoder
Receive bank
switching ID
detection buffer
USB clock
Bit stuff/bit strip
controller
Overflow
Note 4
INTUSBTM
Start
Internal bus
User's Manual U12978EJ3V0UD
Transmit reservation
Note 1 register (HTXRSV,
Counter
Transmit/receive pointer
(USBPOB, USBPOW)
Output
Transmit buffer
latch
Receive buffer
Compare register
INTUSBRD
ENDP
detector
Receive result
Note 3
store register
DTXRSV)
Note 2
CRC
circuit
Packet receive status
register (RXSTAT)
99