Texas Instruments Stellaris LM3S9D90, Руководство пользователя

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July 5, 2011 11
Hardware Description
The EK-LM3S9D90 evaluation kit contains two boards: the EK-LM3S9D90 evaluation board and
the BD-ICDI JTAG debug board as described in more detail in this chapter.
Evaluation Board
The EK-LM3S9D90 evaluation board uses the Stellaris® LM3S9D90 microcontroller and includes
a 10/100 Ethernet port and a USB 2.0 full-speed OTG port. The board is intended for use with the
ICDI board, but can be used as a standalone board as well. Figure 2-1 shows the block diagram.
Figure 2-1. EK-LM3S9D90 Evaluation Board Block Diagram
Functional Description
Microcontroller, Reset, GPIO Pads, and JTAG (Schematic page 20)
Microcontroller
The evaluation board uses the Stellaris LM3S9D90 microcontroller. A 16 MHz crystal provides the
main oscillator clock which can directly drive the ARM core clock or can drive an internal PLL to
increase the core clock up to 80 MHz. A 25 MHz crystal is used for the Ethernet clock and a
4.194304 MHz crystal is used for the real-time clock.
The LM3S9D90 microcontroller has an internal LDO voltage regulator that supplies power for
internal use. This rail requires only three capacitors for decoupling and is not connected to any
other circuits.
Stellaris
LM3S9D90
Ethernet 10/100
5V
GPIOs
USB – OTG
3.3V
Regulator
USB Power
Switch
JTAG/SWD
PWR/UART
UART0
BOARD PADs
RESET
DPDT
VBUS
4.19MHz
25MHz
16MHz
RTC MOSC
Ethernet
USER LED
USER PUSHBUTTON
USB
JTAG
C H A P T E R 2