自制MP3播放器

文章摘要：The MAX chip is a special USB to Li-Ion charger, and it controls the relatively complicated charge sequence to the Li-Ion cell.The Li-Ion cell (or Ni-Mh cells), supply 3.6V to the other components.Memory Card InterfaceThe player can be used with either a Compact Flash card or a MultiMedia Card.The C

自制MP3播放器,标签：电子小制作,http://www.88dzw.com

The MAX chip is a special USB to Li-Ion charger, and it controls the relatively complicated charge sequence to the Li-Ion cell.

The Li-Ion cell (or Ni-Mh cells), supply 3.6V to the other components.

Memory Card Interface

The player can be used with either a Compact Flash card or a MultiMedia Card.

The Compact Flash (CF) interface is pretty similar to a standard ATA interface. The nice thing about it, is that it can run in 8-bit mode, making it very simple to interface to a microprocessor.

In the yampp-7, the CF interface is mapped directly into the memorymap of the processor. To control the CF card and to read/write data, the standard ATA register bank of is used, and address bits A8-A11 is used to select the register.

The MultiMedia Interface is a serial interface with an SPI bus. As the mega161 already has such a bus, the MultiMedia card is simply hooked onto this bus, with a single address line used as chip select.

Address decoding

To simplify the addressing of the CF card and USB interface, a 74HC00 is used to gate the RD and WR signals to the USB chip depending on the state of address line A15. With this, the USB chip will be LOCated at address 0x8000, and the CF card's registers are located at 0x1000 to 0x1F00.

MP3 Decoder

The MP3 decoder is, as on other yampp's the VS1001K chip from VLSI. It's an easy to use decoder with a built in DAC. It's clocked from a 12.288 MHz Crystal, enabling bitrates up to 256k bps.

It also has a built in headphone amplifier.

Player control

The player is controlled with 4 pushbuttons. One of these is connected to the ICP input of the CPU, which can generate an interrupt to the CPU. When the player is stopped, it enters power-down mode after 1 minute. The interrupt from the button can then be used to wakeup the CPU from the low-power sleep mode.

All buttons have two functions, one is reached by a short press on the button, and the other by holding down the button. Depending on player state, the buttons control various functio

Partslist

PartvaluePackage

--------------------- -----------------

R1,R610k R0805

R2,R3100RR0805 *

R4 1MR0805

R5,R8,R114k7 R0805

R71k5R0805

R102k2R0805

R12470R0805

R1333kR0805

R14,R1527 R0805

R1651kR0805

C1,C6,C7 100nFC0805

C9-C11 100nFC0805

C2-C533pFC0805

C8 10uF/16ELNA_RV2_4

C14 10uF/16 Tantal ! C6032

C15 1uF/16 Tantal C3528

C12,C13100uF/10ELNA_RV2_63

D1 BAS32 SOD80 *

T2 BC817 SOT23

IC1ATmega161LTQFP44

IC2VS1001K SOIC-28

IC474HC00D SO14

IC5MAX1811 SO8 **

IC6FT8U245BM QFP32

Q1 4.000MHzHC49U-V Crystal

Q2 12.288MHz HC49U-V Crystal

Q3 6.00MHz Ceramic Resonator

J1 Compact Flash Connector

J2 LCD/Programming Angled Connector 2*5 2mm

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