NEC switch - Manual (Page 150)

CHAPTER 8 USB FUNCTION
User’s Manual U12978EJ3V0UD
150
8.8.4 NRZI encoder operation
This circuit performs NRZI encoding of data to be transmitted.
Figure 8-30. Timing of NRZI Encoder Operation
Data
before encoding
USB clock generation
NRZI encoding
Transmit packet
Sync pattern Data/handshake packet
Figure 8-31. Flow Chart of NRZI Encoder Operation
Y
Y
Y
N
N
Idle state
Idle state
Sync.0 input
Next bit input
Reverse output level
Reverse output level
(1 output)
Transmit start?
Input bit = 0?
Was
EOP transmit signal
set?
Maintain
previous output level
N