Cypress CY7C68000A Manual De Usuario

Document #: 38-08052 Rev. *G

Page 3 of 15

The operational modes are controlled by the OpMode signals.

The OpMode signals are capable of inhibiting normal operation

of the transceiver and evoking special test

 

modes. These modes

take effect immediately and take precedence over any pending

data operations. The transmission data rate when in OpMode

depends on the state of the XcvrSelect input.

Mode 0 enables the transceiver to operate with normal USB data

decoding and encoding.
Mode 1 enables the transceiver logic to support a soft disconnect

feature that tri-states both the HS and FS transmitters, and

removes any termination from the USB, making it appear to an

upstream port that the device is disconnected from the bus.
Mode 2 disables Bit Stuff and NRZI encoding logic so ‘1’s loaded

from the data bus becomes ‘J’s on the DPLUS/DMINUS lines

and ‘0’s become ‘K’s.

The CY7C68000A does not require external resistors for USB

data line impedance termination or an external pull up resistor on

the DPLUS line. These resistors are incorporated into the part.

They are factory trimmed to meet the requirements of USB 2.0.

Incorporating these resistors also reduces the pin count on the

part.

00

0

Normal operation

01

1

Non-driving

10

2

Disable Bit Stuffing and NRZI 

encoding

11

3

Reserved