LM3S8971 Luminary Micro, Inc, LM3S8971 Datasheet - Page 37

• Manufacturer Part Number: LM3S8971
• Description: Lm3s8971 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

1.4.4.3
1.4.4.4
1.4.5
1.4.5.1
1.4.5.2
July 26, 2008
The SSI module can be configured as either a master or slave device. As a slave device, the SSI
module can also be configured to disable its output, which allows a master device to be coupled
with multiple slave devices.
The SSI module also includes a programmable bit rate clock divider and prescaler to generate the
output serial clock derived from the SSI module's input clock. Bit rates are generated based on the
input clock and the maximum bit rate is determined by the connected peripheral.
Controller Area Network (see page 380)
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 a more robust twisted-pair
wire. Originally created for automotive purposes, now it is used in many embedded control
applications (for example, industrial or medical). Bit rates up to 1Mb/s are possible at network lengths
below 40 meters. Decreased bit rates allow longer network distances (for example, 125 Kb/s 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 LM3S8971 includes one CAN units.
Ethernet Controller (see page 421)
Ethernet is a frame-based computer networking technology for local area networks (LANs). Ethernet
has been standardized as IEEE 802.3. It defines a number of wiring and signaling standards for the
physical layer, two means of network access at the Media Access Control (MAC)/Data Link Layer,
and a common addressing format.
The Stellaris® Ethernet Controller consists of a fully integrated media access controller (MAC) and
network physical (PHY) interface device. The Ethernet Controller conforms to IEEE 802.3
specifications and fully supports 10BASE-T and 100BASE-TX standards. In addition, the Ethernet
Controller supports automatic MDI/MDI-X cross-over correction.
System Peripherals
Programmable GPIOs (see page 168)
General-purpose input/output (GPIO) pins offer flexibility for a variety of connections.
The Stellaris
individual GPIO port. The GPIO module is FiRM-compliant (compliant to the ARM Foundation IP
for Real-Time Microcontrollers specification) and supports 4-38 programmable input/output pins.
The number of GPIOs available depends on the peripherals being used (see “Signal Tables” on page
531 for the signals available to each GPIO pin).
The GPIO module features programmable interrupt generation as either edge-triggered or
level-sensitive on all pins, programmable control for GPIO pad configuration, and bit masking in
both read and write operations through address lines. Pins configured as digital inputs are
Schmitt-triggered.
Four Programmable Timers (see page 210)
Programmable timers can be used to count or time external events that drive the Timer input pins.
The Stellaris
block provides two 16-bit timers/counters that can be configured to operate independently as timers
®
®
GPIO module is comprised of eight physical GPIO blocks, each corresponding to an
General-Purpose Timer Module (GPTM) contains four GPTM blocks. Each GPTM
Preliminary
LM3S8971 Microcontroller
37