Texas Instruments EKS-LM3S1968 Evaluation Kit with Code Composer Studio EKS-LM3S1968 EKS-LM3S1968 데이터 시트
제품 코드
EKS-LM3S1968
January 6, 2010
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Hardware Description
In addition to a microcontroller, the Stellaris LM3S1968 evaluation board includes a range of useful
peripherals and an integrated in-circuit debug interface (ICDI). This chapter describes how these
peripherals operate and interface to the microcontroller.
peripherals and an integrated in-circuit debug interface (ICDI). This chapter describes how these
peripherals operate and interface to the microcontroller.
LM3S1968 Evaluation Board
LM3S1968 Microcontroller Overview
The heart of the EVB is a Stellaris LM3S1968 ARM Cortex-M3-based microcontroller. The
LM3S1968 offers 256-KB Flash memory, 50-MHz operation, and a wide range of peripherals.
Refer to the LM3S1968 data sheet (order number DS-LM3S1968) for complete device details.
LM3S1968 offers 256-KB Flash memory, 50-MHz operation, and a wide range of peripherals.
Refer to the LM3S1968 data sheet (order number DS-LM3S1968) for complete device details.
The LM3S1968 microcontroller is factory programmed with a quickstart demo program. The
quickstart program resides in the LM3S1968 on-chip Flash memory and runs each time power is
applied unless the quickstart has been replaced with a user program.
quickstart program resides in the LM3S1968 on-chip Flash memory and runs each time power is
applied unless the quickstart has been replaced with a user program.
Hibernation Module
The Hibernation Module manages removal and restoration of power to the microcontroller and
peripherals while maintaining a real-time clock (RTC) and non-volatile memory. The EVB includes
a 3 V Lithium battery to maintain Hibernate module power when USB power is unavailable.
peripherals while maintaining a real-time clock (RTC) and non-volatile memory. The EVB includes
a 3 V Lithium battery to maintain Hibernate module power when USB power is unavailable.
The Hibernation state is initiated in software. Leaving Hibernation mode requires either an RTC
timer match event or assertion of the WAKE signal. Pressing the Select switch on the EVB asserts
WAKE
timer match event or assertion of the WAKE signal. Pressing the Select switch on the EVB asserts
WAKE
. The Hibernate LED (LED4) signals that the EVB is in Hibernate state (+3.3 V disabled) as
long as USB power is present. When USB power is removed, the EVB will remain in the Hibernate
state, however, the LED will not be on.
state, however, the LED will not be on.
Clocking
The EVB uses an 8.0-MHz crystal to complete the LM3S1968 microcontroller's main internal clock
circuit. An internal PLL, configured in software, multiples this clock to 50 MHz for core and
peripheral timing.
circuit. An internal PLL, configured in software, multiples this clock to 50 MHz for core and
peripheral timing.
The real-time clock oscillator is part of the microcontroller's Hibernation module and uses a
4.194304 MHz crystal for timing. This frequency divides by 128 to generate a 32.7680 kHz
standard timing frequency.
4.194304 MHz crystal for timing. This frequency divides by 128 to generate a 32.7680 kHz
standard timing frequency.
Reset
The LM3S1968 microcontroller shares its external reset input with the OLED display. In the EVB,
reset sources are gated through the CPLD, though in a typical application a simple wired-OR
arrangement is sufficient.
reset sources are gated through the CPLD, though in a typical application a simple wired-OR
arrangement is sufficient.
External reset is asserted (active low) under any one of three conditions:
Power-on reset
Reset push switch SW1 held down
C H A P T E R 2