LM3S1958 Datasheet, PDF (28/435 Pages) List of Unclassifed Manufacturers – Microcontroller

Architectural Overview
1.4.4
1.4.4.1
1.4.4.2
1.4.4.3
The I²C bus interfaces to external I²C devices such as serial memory (RAMs and ROMs), networking
devices, LCDs, tone generators, and so on. The I²C bus may also be used for system testing and
diagnostic purposes in product development and manufacture.
The LM3S1958 controller includes two I²C modules that provide the ability to communicate to other
IC devices over an I²C bus. The I²C bus supports devices that can both transmit and receive (write
and read) data.
Devices on the I²C bus can be designated as either a master or a slave. Each I²C module supports
both sending and receiving data as either a master or a slave, and also supports the simultaneous
operation as both a master and a slave. The four I²C modes are: Master Transmit, Master Receive,
Slave Transmit, and Slave Receive.
A Stellaris^® I²C module can operate at two speeds: Standard (100 Kbps) and Fast (400 Kbps).
Both the I²C master and slave can generate interrupts. The I²C master generates interrupts when
a transmit or receive operation completes (or aborts due to an error). The I²C slave generates
interrupts when data has been sent or requested by a master.
System Peripherals
Programmable GPIOs (see page 148)
General-purpose input/output (GPIO) pins offer flexibility for a variety of connections.
The Stellaris^® GPIO module is composed of eight physical GPIO blocks, each corresponding to an
individual GPIO port. The GPIO module is FiRM-compliant (compliant to the ARM Foundation IP
for Real-Time Microcontrollers specification) and supports 21-52 programmable input/output pins.
The number of GPIOs available depends on the peripherals being used (see “Signal Tables” on page
389 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.
Four Programmable Timers (see page 189)
Programmable timers can be used to count or time external events that drive the Timer input pins.
The Stellaris^® General-Purpose Timer Module (GPTM) contains four GPTM blocks. Each GPTM
block provides two 16-bit timer/counters that can be configured to operate independently as timers
or event counters, or configured to operate as one 32-bit timer or one 32-bit Real-Time Clock (RTC).
Timers can also be used to trigger analog-to-digital (ADC) conversions.
When configured in 32-bit mode, a timer can run as a one-shot timer, periodic timer, or Real-Time
Clock (RTC). When in 16-bit mode, a timer can run as a one-shot timer or periodic timer, and can
extend its precision by using an 8-bit prescaler. A 16-bit timer can also be configured for event
capture or Pulse Width Modulation (PWM) generation.
Watchdog Timer (see page 222)
A watchdog timer can generate nonmaskable interrupts (NMIs) or a reset when a time-out value is
reached. The watchdog timer is used to regain control when a system has failed due to a software
error or to the failure of an external device to respond in the expected way.
The Stellaris^® Watchdog Timer module consists of a 32-bit down counter, a programmable load
register, interrupt generation logic, and a locking register.
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June 14, 2007
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