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This simple
design creates a small, hand-held, battery operated, portable
MP3 player using an MSP430F123 for overall system control, a MultiMediaCard
(MMC) for data storage and VLSI’s VS1001K chip for MP3 decoding
and sound amplification. Two 1.5 Volt, AAA size, batteries are
connected in series to give a raw voltage of three volts (nominal).
This is fed into a voltage booster that creates 3.3 Volts from
input voltages as low as 1.2 Volts. The boosted voltage is then
routed to a semiconductor power switch. This power switch is controlled
via software, and is enabled after the uP (microprocessor) is
reset, and shut down at power-off. Initial startup voltage is
conducted via a user pressed ON button which enables the voltage
booster to supply operating voltage to the uP. After being powered
by the manual button, and subsequently running, the uP then enables
the power switch, after which the user button may be released.
The M430F123
processor has 8KB of regular program flash memory and 256 bytes
of data RAM. It also includes several built in peripheral devices
of which this project uses, including the built in Serial Peripheral
Interface (SPI) and Universal Asynchronous Receiver/Transmitter
(UART), a 16-bit timer, and a voltage comparator. Also used are
several digital I/O lines.
Block
Diagram
Jeff Pollard
California,
USA
xylotex@hotmail.com
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