LM3S9B81 Datasheet, PDF (51/1155 Pages) Texas Instruments – Stellaris® LM3S9B81 Microcontroller

Stellaris® LM3S9B81 Microcontroller
1.1.4.2
1.1.4.3
– Receive channel request asserted on packet receipt
– Transmit channel request asserted on empty transmit FIFO
Controller Area Network (see page 751)
Controller Area Network (CAN) is a multicast shared serial-bus standard for connecting electronic
control units (ECUs). CAN was specifically designed to be robust in electromagnetically noisy
environments and can utilize a differential balanced line like RS-485 or twisted-pair wire. Originally
created for automotive purposes, it is now used in many embedded control applications (for example,
industrial or medical). Bit rates up to 1 Mbps are possible at network lengths below 40 meters.
Decreased bit rates allow longer network distances (for example, 125 Kbps at 500m).
A transmitter sends a message to all CAN nodes (broadcasting). Each node decides on the basis
of the identifier received whether it should process the message. The identifier also determines the
priority that the message enjoys in competition for bus access. Each CAN message can transmit
from 0 to 8 bytes of user information.
The LM3S9B81 microcontroller includes three CAN units with the following features:
■ CAN protocol version 2.0 part A/B
■ Bit rates up to 1 Mbps
■ 32 message objects with individual identifier masks
■ Maskable interrupt
■ Disable Automatic Retransmission mode for Time-Triggered CAN (TTCAN) applications
■ Programmable Loopback mode for self-test operation
■ Programmable FIFO mode enables storage of multiple message objects
■ Gluelessly attaches to an external CAN transceiver through the CANnTX and CANnRX signals
USB (see page 863)
Universal Serial Bus (USB) is a serial bus standard designed to allow peripherals to be connected
and disconnected using a standardized interface without rebooting the system.
The LM3S9B81 controller supports three configurations in USB 2.0 full and low speed: USB Device,
USB Host, and USB On-The-Go (negotiated on-the-go as host or device when connected to other
USB-enabled systems).
The USB module has the following features:
■ Complies with USB-IF certification standards
■ USB 2.0 full-speed (12 Mbps) and low-speed (1.5 Mbps) operation
■ Integrated PHY
■ 4 transfer types: Control, Interrupt, Bulk, and Isochronous
■ 32 endpoints
– 1 dedicated control IN endpoint and 1 dedicated control OUT endpoint
June 29, 2010
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Texas Instruments-Advance Information