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Luminary Micro may make changes to specications and product descriptions at any time, without notice. Contact your local Luminary Micro sales ofce
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Designers must not rely on the absence or characteristics of any features or instructions marked "reserved" or "undened." Luminary Micro reserves these
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Preliminary
November 29, 20072
LM3S102 Microcontroller
Table of Contents
About This Document .................................................................................................................... 14
Register 4:Analog Comparator Reference Voltage Control (ACREFCTL), offset 0x10 ......................... 329
Register 5:Analog Comparator Status 0 (ACSTAT0), offset 0x20 ....................................................... 330
Register 6:Analog Comparator Control 0 (ACCTL0), offset 0x24 ....................................................... 331
13November 29, 2007
Preliminary
About This Document
About This Document
This data sheet provides reference information for the LM3S102 microcontroller, describing the
functional blocks of the system-on-chip (SoC) device designed around the ARM® Cortex™-M3
core.
Audience
This manual is intended for system software developers, hardware designers, and application
developers.
About This Manual
This document is organized into sections that correspond to each major feature.
Related Documents
The following documents are referenced by the data sheet, and available on the documentation CD
or from the Luminary Micro web site at www.luminarymicro.com:
The following related documents are also referenced:
■
IEEE Standard 1149.1-Test Access Port and Boundary-Scan Architecture
This documentation list was current as of publication date. Please check the Luminary Micro web
site for additional documentation, including application notes and white papers.
Documentation Conventions
This document uses the conventions shown in Table 1 on page 14.
Table 1. Documentation Conventions
MeaningNotation
General Register Notation
REGISTER
offset 0xnnn
Register N
APB registers are indicated in uppercase bold. For example, PBORCTL is the Power-On and
Brown-Out Reset Control register. If a register name contains a lowercase n, it represents more
than one register. For example, SRCRn represents any (or all) of the three Software Reset Control
registers: SRCR0, SRCR1 , and SRCR2.
A single bit in a register.bit
Two or more consecutive and related bits.bit field
A hexadecimal increment to a register's address, relative to that module's base address as specified
in “Memory Map” on page 34.
Registers are numbered consecutively throughout the document to aid in referencing them. The
register number has no meaning to software.
Preliminary
November 29, 200714
reserved
yy:xx
Register Bit/Field
Types
R/W1C
W1C
Reset Value
Pin/Signal Notation
assert a signal
SIGNAL
SIGNAL
Numbers
X
0x
LM3S102 Microcontroller
MeaningNotation
Register bits marked reserved are reserved for future use. In most cases, reserved bits are set to
0; however, user software should not rely on the value of a reserved bit. To provide software
compatibility with future products, the value of a reserved bit should be preserved across a
read-modify-write operation.
The range of register bits inclusive from xx to yy. For example, 31:15 means bits 15 through 31 in
that register.
This value in the register bit diagram indicates whether software running on the controller can
change the value of the bit field.
Software can read this field. The bit or field is cleared by hardware after reading the bit/field.RC
Software can read this field. Always write the chip reset value.RO
Software can read or write this field.R/W
Software can read or write this field. A write of a 0 to a W1C bit does not affect the bit value in the
register. A write of a 1 clears the value of the bit in the register; the remaining bits remain unchanged.
This register type is primarily used for clearing interrupt status bits where the read operation
provides the interrupt status and the write of the read value clears only the interrupts being reported
at the time the register was read.
Software can write this field. A write of a 0 to a W1C bit does not affect the bit value in the register.
A write of a 1 clears the value of the bit in the register; the remaining bits remain unchanged. A
read of the register returns no meaningful data.
This register is typically used to clear the corresponding bit in an interrupt register.
Only a write by software is valid; a read of the register returns no meaningful data.WO
This value in the register bit diagram shows the bit/field value after any reset, unless noted.Register Bit/Field
Bit cleared to 0 on chip reset.0
Bit set to 1 on chip reset.1
Nondeterministic.-
Pin alternate function; a pin defaults to the signal without the brackets.[ ]
Refers to the physical connection on the package.pin
Refers to the electrical signal encoding of a pin.signal
Change the value of the signal from the logically False state to the logically True state. For active
High signals, the asserted signal value is 1 (High); for active Low signals, the asserted signal value
is 0 (Low). The active polarity (High or Low) is defined by the signal name (see SIGNAL and SIGNAL
below).
Change the value of the signal from the logically True state to the logically False state.deassert a signal
Signal names are in uppercase and in the Courier font. An overbar on a signal name indicates that
it is active Low. To assert SIGNAL is to drive it Low; to deassert SIGNAL is to drive it High.
Signal names are in uppercase and in the Courier font. An active High signal has no overbar. To
assert SIGNAL is to drive it High; to deassert SIGNAL is to drive it Low.
An uppercase X indicates any of several values is allowed, where X can be any legal pattern. For
example, a binary value of 0X00 can be either 0100 or 0000, a hex value of 0xX is 0x0 or 0x1, and
so on.
Hexadecimal numbers have a prefix of 0x. For example, 0x00FF is the hexadecimal number FF.
All other numbers within register tables are assumed to be binary. Within conceptual information,
binary numbers are indicated with a b suffix, for example, 1011b, and decimal numbers are written
without a prefix or suffix.
Preliminary
15November 29, 2007
Architectural Overview
1Architectural Overview
The Luminary Micro Stellaris®family of microcontrollers—the first ARM® Cortex™-M3 based
controllers—brings high-performance 32-bit computing to cost-sensitive embedded microcontroller
applications. These pioneering parts deliver customers 32-bit performance at a cost equivalent to
legacy 8- and 16-bit devices, all in a package with a small footprint.
The LM3S102 microcontroller is targeted for industrial applications, including test and measurement
equipment, factory automation, HVAC and building control, motion control, medical instrumentation,
fire and security, and power/energy.
In addition, the LM3S102 microcontroller offers the advantages of ARM's widely available
development tools, System-on-Chip (SoC) infrastructure IP applications, and a large user community.
Additionally, the microcontroller uses ARM's Thumb®-compatible Thumb-2 instruction set to reduce
memory requirements and, thereby, cost. Finally, the LM3S102 microcontroller is code-compatible
to all members of the extensive Stellaris®family; providing flexibility to fit our customers' precise
needs.
Luminary Micro offers a complete solution to get to market quickly, with evaluation and development
boards, white papers and application notes, an easy-to-use peripheral driver library, and a strong
support, sales, and distributor network.
1.1Product Features
The LM3S102 microcontroller includes the following product features:
■ 32-Bit RISC Performance
– 32-bit ARM® Cortex™-M3 v7M architecture optimized for small-footprint embedded
applications
– System timer (SysTick), providing a simple, 24-bit clear-on-write, decrementing, wrap-on-zero
counter with a flexible control mechanism
– Thumb®-compatible Thumb-2-only instruction set processor core for high code density
– 20-MHz operation
– Hardware-division and single-cycle-multiplication
Figure 1-1 on page 21 represents the full set of features in the Stellaris®100 series of devices; not
all features may be available on the LM3S102 microcontroller.
Preliminary
November 29, 200720
Figure 1-1. Stellaris®100 Series High-Level Block Diagram
LM3S102 Microcontroller
1.4Functional Overview
The following sections provide an overview of the features of the LM3S102 microcontroller. The
page number in parenthesis indicates where that feature is discussed in detail. Ordering and support
information can be found in “Ordering and Contact Information” on page 368.
1.4.1ARM Cortex™-M3
1.4.1.1Processor Core (see page 28)
All members of the Stellaris®product family, including the LM3S102 microcontroller, are designed
around an ARM Cortex™-M3 processor core. The ARM Cortex-M3 processor provides the core for
a high-performance, low-cost platform that meets the needs of minimal memory implementation,
reduced pin count, and low-power consumption, while delivering outstanding computational
performance and exceptional system response to interrupts.
“ARM Cortex-M3 Processor Core” on page 28 provides an overview of the ARM core; the core is
detailed in the ARM® Cortex™-M3 Technical Reference Manual.
21November 29, 2007
Preliminary
Architectural Overview
1.4.1.2System Timer (SysTick)
Cortex-M3 includes an integrated system timer, SysTick. SysTick provides a simple, 24-bit
clear-on-write, decrementing, wrap-on-zero counter with a flexible control mechanism. The counter
can be used in several different ways, for example:
■ An RTOS tick timer which fires at a programmable rate (for example, 100 Hz) and invokes a
SysTick routine.
■ A high-speed alarm timer using the system clock.
■ A variable rate alarm or signal timer—the duration is range-dependent on the reference clock
used and the dynamic range of the counter.
■ A simple counter. Software can use this to measure time to completion and time used.
■ An internal clock source control based on missing/meeting durations. The COUNTFLAG bit-field
in the control and status register can be used to determine if an action completed within a set
duration, as part of a dynamic clock management control loop.
The LM3S102 controller includes the ARM Nested Vectored Interrupt Controller (NVIC) on the ARM
Cortex-M3 core. The NVIC and Cortex-M3 prioritize and handle all exceptions. All exceptions are
handled in Handler Mode. The processor state is automatically stored to the stack on an exception,
and automatically restored from the stack at the end of the Interrupt Service Routine (ISR). The
vector is fetched in parallel to the state saving, which enables efficient interrupt entry. The processor
supports tail-chaining, which enables back-to-back interrupts to be performed without the overhead
of state saving and restoration. Software can set eight priority levels on 7 exceptions (system
handlers) and 14 interrupts.
“Interrupts” on page 36 provides an overview of the NVIC controller and the interrupt map. Exceptions
and interrupts are detailed in the ARM® Cortex™-M3 Technical Reference Manual.
1.4.2Motor Control Peripherals
To enhance motor control, the LM3S102 controller features Pulse Width Modulation (PWM) outputs.
1.4.2.1PWM
Pulse width modulation (PWM) is a powerful technique for digitally encoding analog signal levels.
High-resolution counters are used to generate a square wave, and the duty cycle of the square
wave is modulated to encode an analog signal. Typical applications include switching power supplies
and motor control.
On the LM3S102, PWM motion control functionality can be achieved through:
■ The motion control features of the general-purpose timers using the CCP pins
CCP Pins (see page 159)
The General-Purpose Timer Module's CCP (Capture Compare PWM) pins are software programmable
to support a simple PWM mode with a software-programmable output inversion of the PWM signal.
1.4.3Analog Peripherals
For support of analog signals, the LM3S102 microcontroller offers one analog comparator.
November 29, 200722
Preliminary
1.4.3.1Analog Comparators (see page 322)
An analog comparator is a peripheral that compares two analog voltages, and provides a logical
output that signals the comparison result.
A comparator can compare a test voltage against any one of these voltages:
■ An individual external reference voltage
■ A shared single external reference voltage
■ A shared internal reference voltage
The comparator can provide its output to a device pin, acting as a replacement for an analog
comparator on the board, or it can be used to signal the application via interrupts to cause it to start
capturing a sample sequence.
1.4.4Serial Communications Peripherals
The LM3S102 controller supports both asynchronous and synchronous serial communications with:
■ One fully programmable 16C550-type UART
LM3S102 Microcontroller
■ One SSI module
■ One I2C module
1.4.4.1UART (see page 212)
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 LM3S102 controller includes one fully programmable 16C550-type UARTthat supports data
transfer speeds up to 460.8 Kbps. (Although similar in functionality to a 16C550 UART, it is not
register-compatible.)
Separate 16x8 transmit (TX) and 16x12 receive (RX) FIFOs reduce CPU interrupt service loading.
The UART can generate individually masked interrupts from the RX, TX, modem status, and error
conditions. The module provides a single combined interrupt when any of the interrupts are asserted
and are unmasked.
1.4.4.2SSI (see page 250)
Synchronous Serial Interface (SSI) is a four-wire bi-directional communications interface.
The LM3S102 controller includes one SSI module that provides the functionality for synchronous
serial communications with peripheral devices, and can be configured to use the Freescale SPI,
MICROWIRE, or TI synchronous serial interface frame formats. The size of the data frame is also
configurable, and can be set between 4 and 16 bits, inclusive.
The SSI module performs serial-to-parallel conversion on data received from a peripheral device,
and parallel-to-serial conversion on data transmitted to a peripheral device. The TX and RX paths
are buffered with internal FIFOs, allowing up to eight 16-bit values to be stored independently.
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.
Preliminary
23November 29, 2007
Architectural Overview
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.
1.4.4.3I2C (see page 287)
The Inter-Integrated Circuit (I2C) bus provides bi-directional data transfer through a two-wire design
(a serial data line SDA and a serial clock line SCL).
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 LM3S102 controller includes one I2C module that provides 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. The 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.
1.4.5System Peripherals
1.4.5.1Programmable GPIOs (see page 114)
General-purpose input/output (GPIO) pins offer flexibility for a variety of connections.
The Stellaris®GPIO module is composed of three 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 0-18 programmable input/output pins.
The number of GPIOs available depends on the peripherals being used (see “Signal Tables” on page
334 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.
1.4.5.2Two Programmable Timers (see page 153)
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 two GPTM blocks. Each GPTM
block provides two 16-bit timers/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).
When configured in 32-bit mode, a timer can run as a Real-Time Clock (RTC), one-shot timer or
periodic timer. 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.
November 29, 200724
Preliminary
1.4.5.3Watchdog Timer (see page 189)
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.
The Watchdog Timer can be configured to generate an interrupt to the controller on its first time-out,
and to generate a reset signal on its second time-out. Once the Watchdog Timer has been configured,
the lock register can be written to prevent the timer configuration from being inadvertently altered.
1.4.6Memory Peripherals
The LM3S102 controller offers both single-cycle SRAM and single-cycle Flash memory.
1.4.6.1SRAM (see page 98)
The LM3S102 static random access memory (SRAM) controller supports 2 KB SRAM. The internal
SRAM of the Stellaris®devices is located at offset 0x0000.0000 of the device memory map. To
reduce the number of time-consuming read-modify-write (RMW) operations, ARM has introduced
bit-banding technology in the new Cortex-M3 processor. With a bit-band-enabled processor, certain
regions in the memory map (SRAM and peripheral space) can use address aliases to access
individual bits in a single, atomic operation.
LM3S102 Microcontroller
1.4.6.2Flash (see page 99)
The LM3S102 Flash controller supports 8 KB of flash memory. The flash is organized as a set of
1-KB blocks that can be individually erased. Erasing a block causes the entire contents of the block
to be reset to all 1s. These blocks are paired into a set of 2-KB blocks that can be individually
protected. The blocks can be marked as read-only or execute-only, providing different levels of code
protection. Read-only blocks cannot be erased or programmed, protecting the contents of those
blocks from being modified. Execute-only blocks cannot be erased or programmed, and can only
be read by the controller instruction fetch mechanism, protecting the contents of those blocks from
being read by either the controller or by a debugger.
1.4.7Additional Features
1.4.7.1Memory Map (see page 34)
A memory map lists the location of instructions and data in memory. The memory map for the
LM3S102 controller can be found in “Memory Map” on page 34. Register addresses are given as
a hexadecimal increment, relative to the module's base address as shown in the memory map.
The ARM® Cortex™-M3 Technical Reference Manual provides further information on the memory
map.
1.4.7.2JTAG TAP Controller (see page 38)
The Joint Test Action Group (JTAG) port provides a standardized serial interface for controlling the
Test Access Port (TAP) and associated test logic. The TAP, JTAG instruction register, and JTAG
data registers can be used to test the interconnects of assembled printed circuit boards, obtain
manufacturing information on the components, and observe and/or control the inputs and outputs
of the controller during normal operation. The JTAG port provides a high degree of testability and
chip-level access at a low cost.
Preliminary
25November 29, 2007
Architectural Overview
The JTAG port is comprised of the standard five pins: TRST, TCK, TMS, TDI, and TDO. Data is
transmitted serially into the controller on TDI and out of the controller on TDO. The interpretation of
this data is dependent on the current state of the TAP controller. For detailed information on the
operation of the JTAG port and TAP controller, please refer to the IEEE Standard 1149.1-TestAccess Port and Boundary-Scan Architecture.
The Luminary Micro JTAG controller works with the ARM JTAG controller built into the Cortex-M3
core. This is implemented by multiplexing the TDO outputs from both JTAG controllers. ARM JTAG
instructions select the ARM TDO output while Luminary Micro JTAG instructions select the Luminary
Micro TDO outputs. The multiplexer is controlled by the Luminary Micro JTAG controller, which has
comprehensive programming for the ARM, Luminary Micro, and unimplemented JTAG instructions.
1.4.7.3System Control and Clocks (see page 48)
System control determines the overall operation of the device. It provides information about the
device, controls the clocking of the device and individual peripherals, and handles reset detection
and reporting.
1.4.8Hardware Details
Details on the pins and package can be found in the following sections:
The ARM Cortex-M3 processor provides the core for a high-performance, low-cost platform that
meets the needs of minimal memory implementation, reduced pin count, and low power consumption,
while delivering outstanding computational performance and exceptional system response to
interrupts. Features include:
■ Compact core.
■ Thumb-2 instruction set, delivering the high-performance expected of an ARM core in the memory
size usually associated with 8- and 16-bit devices; typically in the range of a few kilobytes of
memory for microcontroller class applications.
■ Rapid application execution through Harvard architecture characterized by separate buses for
instruction and data.
■ Exceptional interrupt handling, by implementing the register manipulations required for handling
an interrupt in hardware.
■ Migration from the ARM7™ processor family for better performance and power efficiency.
■ Full-featured debug solution with a:
– Serial Wire JTAG Debug Port (SWJ-DP)
– Flash Patch and Breakpoint (FPB) unit for implementing breakpoints
– Data Watchpoint and Trigger (DWT) unit for implementing watchpoints, trigger resources,
and system profiling
– Instrumentation Trace Macrocell (ITM) for support of printf style debugging
– Trace Port Interface Unit (TPIU) for bridging to a Trace Port Analyzer
The Stellaris®family of microcontrollers builds on this core to bring high-performance 32-bit computing
to cost-sensitive embedded microcontroller applications, such as factory automation and control,
industrial control power devices, building and home automation, and stepper motors.
For more information on the ARM Cortex-M3 processor core, see the ARM® Cortex™-M3 Technical
Reference Manual. For information on SWJ-DP, see the ARM® CoreSight Technical Reference
Manual.
Preliminary
November 29, 200728
2.1Block Diagram
Private Peripheral
Bus
(internal)
Data
Watchpoint
and Trace
Interrupts
Debug
Sleep
Instrumentation
Trace Macrocell
Trace
Port
Interface
Unit
CM3 Core
InstructionsData
Flash
Patch and
Breakpoint
Adv. High-
Perf. Bus
Access Port
Nested
Vectored
Interrupt
Controller
Serial Wire JTAG
Debug Port
Bus
Matrix
Adv. Peripheral
Bus
I-code bus
D-code bus
System bus
ROM
Table
Private
Peripheral
Bus
(external)
Serial
Wire
Output
Trace
Port
(SWO)
ARM
Cortex-M3
Figure 2-1. CPU Block Diagram
LM3S102 Microcontroller
2.2Functional Description
Important:
Luminary Micro has implemented the ARM Cortex-M3 core as shown in Figure 2-1 on page 29. As
noted in the ARM® Cortex™-M3 Technical Reference Manual, several Cortex-M3 components are
flexible in their implementation: SW/JTAG-DP, ETM, TPIU, the ROM table, the MPU, and the Nested
Vectored Interrupt Controller (NVIC). Each of these is addressed in the sections that follow.
2.2.1Serial Wire and JTAG Debug
Luminary Micro has replaced the ARM SW-DP and JTAG-DP with the ARM CoreSight™-compliant
Serial Wire JTAG Debug Port (SWJ-DP) interface. This means Chapter 12, “Debug Port,” of the
ARM® Cortex™-M3 Technical Reference Manual does not apply to Stellaris®devices.
The SWJ-DP interface combines the SWD and JTAG debug ports into one module. See the
CoreSight™ Design Kit Technical Reference Manual for details on SWJ-DP.
2.2.2Embedded Trace Macrocell (ETM)
ETM was not implemented in the Stellaris®devices. This means Chapters 15 and 16 of the ARM®
Cortex™-M3 Technical Reference Manual can be ignored.
The ARM® Cortex™-M3 Technical Reference Manual describes all the features of an
ARM Cortex-M3 in detail. However, these features differ based on the implementation.
This section describes the Stellaris®implementation.
Preliminary
29November 29, 2007
ATB
Interface
Asynchronous FIFO
APB
Interface
Trace Out
(serializer)
Debug
ATB
Slave
Port
APB
Slave
Port
Serial Wire
Trace Port
(SWO)
ARM Cortex-M3 Processor Core
2.2.3Trace Port Interface Unit (TPIU)
The TPIU acts as a bridge between the Cortex-M3 trace data from the ITM, and an off-chip Trace
Port Analyzer. The Stellaris®devices have implemented TPIU as shown in Figure 2-2 on page 30.
This is similar to the non-ETM version described in the ARM® Cortex™-M3 Technical ReferenceManual, however, SWJ-DP only provides SWV output for the TPIU.
Figure 2-2. TPIU Block Diagram
2.2.4ROM Table
The default ROM table was implemented as described in the ARM® Cortex™-M3 Technical
Reference Manual.
2.2.5Memory Protection Unit (MPU)
The LM3S102 controller does not include the memory protection unit (MPU) of the ARM Cortex-M3.
2.2.6Nested Vectored Interrupt Controller (NVIC)
The Nested Vectored Interrupt Controller (NVIC):
■ Facilitates low-latency exception and interrupt handling
■ Controls power management
■ Implements system control registers
The NVIC supports up to 240 dynamically reprioritizable interrupts each with up to 256 levels of
priority. The NVIC and the processor core interface are closely coupled, which enables low latency
interrupt processing and efficient processing of late arriving interrupts. The NVIC maintains knowledge
of the stacked (nested) interrupts to enable tail-chaining of interrupts.
You can only fully access the NVIC from privileged mode, but you can pend interrupts in user-mode
if you enable the Configuration Control Register (see the ARM® Cortex™-M3 Technical Reference
Manual). Any other user-mode access causes a bus fault.
November 29, 200730
Preliminary
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