V
REG(3.3)
D+
D-
V
PU(3.3)
33Ω
33Ω
V
BUS
V
CC(5.0)
0.1µF
V
CC(I/O)
3.3V
0.1µF
nOE
SPEED
SOFTCON
SUSPND
MODE
*
RCV
VMO/FSE0
VPO/VO
VP
VM
GZO
SUSPENDO
RXDI
SE0O
TXDO
RXDPI
RXDMI
TUSB1105
USB TRANSCEIVER
MCU
3.3V
1.5KΩ
0.1µ
F
USB TYPE B
RECEPTACLE
PUENO
PUENON
VBUSI
3.3V
100KΩ
Tied to GND for
Single-Ended Input mode only
USB Connectivity
1657
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
Universal Serial Bus (USB)
29.4.5 USB Function Controller Connectivity With USB Transceivers
To provide a robust USB solution, a system that provides a USB device controller port must implement
certain features. These features include:
•
A USB type-B or mini-B receptacle
•
VBUS power detection
•
Transient suppression
•
A controllable pullup resistor to the D+ or D- line
•
USB-compatible upstream port transceiver
Optional weak pulldown resistors can be used to hold the D+ and D- signals at voltages below the USB
transceiver VIL level when there is no USB host connected to the USB Type B connector. By keeping D+
and D- voltages below VIL, the USB transceiver IDDQ can be reduced. Choice of value for the pulldown
resistors must be made carefully so that the circuit meets the requirements of the
USB Specification
.
The USB function controller only supports implementation as a full-speed USB device. As such, the pullup
resistor must be connected to the D+ signal to indicate implementation of a full-speed USB device.
This device supports a 6-wire connection to the USB transceiver.
Figure 29-96. USB Device Connections on USB Pin Group 0 Using 6-Wire Transceiver
Proper initialization of the device to support this mode of operation requires proper setting of the top-level
pin multiplexing (see