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ML401/ML402/ML403 Evaluation Platform
UG080 (v2.5) May 24, 2006
Detailed Description
R
11. Stereo AC97 Audio Codec
The ML40
x
board has an AC97 audio codec (U14) to permit audio processing. The
National Semiconductor LM4550 Audio Codec supports stereo 16-bit audio with up to
48-kHz sampling. The sampling rate for record and playback can be different.
Note:
The reset for the AC97 codec is shared with the reset signal for the flash memory chips and
is designed to be asserted at power-on or upon system reset.
Separate audio jacks are provided for Microphone, Line In, Line Out, and Headphone. All
jacks are stereo except for Microphone. The Headphone jack is driven by the audio codec's
internal 50-mW amplifier.
summarizes the audio jacks.
12. RS-232 Serial Port
The ML40
x
board contains one male DB-9 RS-232 serial port allowing the FPGA to
communicate serial data with another device. The serial port is wired as a host (DCE)
device. Therefore, a null modem cable is normally required to connect the board to the
serial port on a PC. The serial port is designed to operate up to 115200 Bd. An interface chip
is used to shift the voltage level between FPGA and RS-232 signals.
Note:
The FPGA is only connected to the TX and RX data pins on the serial port. Therefore, other
RS-232 signals, including hardware flow control signals, are not used. Flow control should be
disabled when communicating with a PC.
A secondary serial interface is available by using header J27 to support debug of the USB
controller chip. Header J27 brings out RS-232 voltage level signals for ground, TX data, and
RX data.
13. 16-Character x 2-Line LCD
The ML40
x
board has a 16-character x 2-line LCD (Lumex LCM-S01602DTR/M) on the
board to display text information. Potentiometer R1 adjusts the contrast of the LCD. The
data interface to the LCD is connected to the FPGA to support 4-bit mode only. A level
translator chip is used to shift the voltage level between the FPGA and the LCD.
Caution!
Care should be taken not to scratch or damage the surface of the LCD window. The
protective layer of tape on the top of the screen should be left on for added protection of the
screen's surface.
Table 12:
ML40
x
Audio Jacks
Reference
Designator
Function
Stereo/Mono
J11
Microphone - In
Mono
J12
Analog Line - In
Stereo
J13
Analog Line - Out
Stereo
J14
Headphone - Out
Stereo
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