CY7C68003

Document Number: 001-15775 Rev. *I

Page 10 of 27

Figure 6. Sending RX CMD

USB Data Transmit (NOPID)

In this mode, the Link transmits data on the USB without a Packet Identifier (PID) by sending a TX CMD byte of the NOPID type.

TX2UL asserts NXT (see Figure 8 on page 11) in the first cycle of TX CMD and deasserts NXT when it detects STP to be high. Because

this command does not contain PID data, TX2UL waits for the next data byte before beginning transmission on the USB. When the

last byte is transferred by the TX2UL, the link asserts STP for one cycle and drives data to 00h if no transmit errors occur. The link

does not assert STP before the first byte is transferred by the TX2UL.

Figure 7. USB Data Transmit (NOPID)

CLOCK

DATA[7:0]

DIR

STP

NXT

Turn around

RX CMD

Turn around

Turn around

RX CMD

RX CMD

Turn around

D1

CLOCK

DATA[7:0]

DIR

STP

NXT

D0

TX CMD (NOPID)

D2

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