LM3S8G62 Datasheet, PDF (42/1096 Pages) Texas Instruments – Stellaris® LM3S8G62 Microcontroller

OBSOLETE: TI has discontinued production of this device.
Architectural Overview
1.3.3.2
1.3.3.3
– Separate channels for transmit and receive
– Receive channel request asserted on packet receipt
– Transmit channel request asserted on empty transmit FIFO
Controller Area Network (see page 757)
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 LM3S8G62 microcontroller includes one CAN unit 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
UART (see page 615)
A Universal Asynchronous Receiver/Transmitter (UART) is an integrated circuit used for RS-232C
serial communications, containing a transmitter (parallel-to-serial converter) and a receiver
(serial-to-parallel converter), each clocked separately.
The LM3S8G62 microcontroller includes two fully programmable 16C550-type UARTs. Although
the functionality is similar to a 16C550 UART, this UART design is not register compatible. The
UART can generate individually masked interrupts from the Rx, Tx, modem flow control, modem
status, and error conditions. The module generates a single combined interrupt when any of the
interrupts are asserted and are unmasked.
The two UARTs have the following features:
■ Programmable baud-rate generator allowing speeds up to 5 Mbps for regular speed (divide by
16) and 10 Mbps for high speed (divide by 8)
■ Separate 16x8 transmit (TX) and receive (RX) FIFOs to reduce CPU interrupt service loading
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July 24, 2012
Texas Instruments-Production Data