LM3S5739 Datasheet, PDF (668/856 Pages) Texas Instruments – Stellaris® LM3S5739 Microcontroller

Universal Serial Bus (USB) Controller
17.1 Block Diagram
Figure 17-1. USB Module Block Diagram
Endpoint Control
EP0 – 7
Control
Transmit
Receive
Combine
Endpoints
Host
Transaction
Scheduler
USB PHY
USB Data Lines
D+ and D-
USB FS/LS
PHY
UTM
Synchronization
Data Sync
Timers
Packet
Encode/Decode
Packet Encode
Packet Decode
CRC Gen/Check
FIFO RAM
Controller
Rx
Rx
Buff
Buff
Tx
Tx
Buff
Buff
Cycle Control
DMA
Requests
CPU Interface
Interrupt
Control
EP Reg.
Decoder
Common
Regs
Cycle
Control
Interrupts
AHB bus –
Slave mode
FIFO
Decoder
17.2
Signal Description
Some USB controller signals are alternate functions for some GPIO signals and default to be GPIO
signals at reset. The column in the table below titled "Pin Assignment" lists the possible GPIO pin
placements for these USB signals. The AFSEL bit in the GPIO Alternate Function Select
(GPIOAFSEL) register (page 378) should be set to choose the USB function. The USB0VBUS and
USB0ID signals are configured by clearing the appropriate DEN bit in the GPIO Digital Enable
(GPIODEN) register. For more information on configuring GPIOs, see “General-Purpose Input/Outputs
(GPIOs)” on page 355. The remaining signals (with the word "fixed" in the Pin Assignment column)
have a fixed pin assignment and function.
Table 17-1. USB Signals (100LQFP)
Pin Name
Pin Number Pin Type Buffer Type^a Description
USB0DM
70
I/O
Analog Bidirectional differential data pin (D- per USB specification)
for USB0.
USB0DP
71
I/O
Analog Bidirectional differential data pin (D+ per USB specification)
for USB0.
USB0EPEN
83
O
TTL
Optionally used in Host mode to control an external power
source to supply power to the USB bus.
USB0PFLT
76
I
TTL
Optionally used in Host mode by an external power source
to indicate an error state by that power source.
USB0RBIAS
73
O
Analog 9.1-kΩ resistor (1% precision) used internally for USB analog
circuitry.
a. The TTL designation indicates the pin has TTL-compatible voltage levels.
17.3
Functional Description
Note: A 9.1-kΩ resistor should be connected between the USB0RBIAS and ground. The 9.1-kΩ
resistor should have a 1% tolerance and should be located in close proximity to the
668
November 17, 2011
Texas Instruments-Production Data