TF card MP3 decoding board decoding module 3.75V power supply with 2W mixed mono memory playback

Product parameters

TF card MP3 decoding board, without TF card, supports playing MP3 music files, currently tested with 16GB TF card support, no larger ones have been tested yet

3.7 Lithium battery or USB 5V power supply,

The three white boxes in the upper right corner of the board represent three sets of touch buttons, the middle one is the play pause button, the up and down two sets of short presses are the up and down song buttons, and the up and down two sets of long presses are the volume+- adjustment buttons.

Equipped with a 2W monaural amplifier, the maximum output of the amplifier is 3W when powered by 5V (it is recommended to pair it with a small speaker on a 4 Euro 3W plug-in small speaker for good sound quality and loud sound. If you feel that the volume is not enough, please directly replace it with a 4 Euro 5W speaker. The sound is so loud that it scares you and definitely surprises you. Hehe. After replacing the 4 Euro 5W speaker, pay attention to the heat dissipation of the amplifier chip, and it is best to add heat sinks)

Some customers have reported that the amplifier may generate heat when playing music. It is normal for the amplifier chip or tube to heat up. As long as the amplifier is not turned up to a high volume, the output terminal of the short circuited speaker (with a resistance of 0 ohms) will not burn the amplifier chip, so you can use it with confidence.

Some customers need to go back and use this board as the front stage of the power amplifier. If they don't need the power amplifier of this board, they can go back and connect the power amplifier themselves. They can modify it as follows: remove the power amplifier chip (8-pin chip) from the board, and then connect a 104 (or 224) capacitor in series from the 4th and 6th pins of the main control (these two pins are the left and right channel outputs of the main control chip) to the input terminal of the power amplifier (the capacitor acts as an isolation to prevent burning of the front stage main control chip or later power amplifier tubes when the same power supply is used). The remaining wire is connected from the negative terminal to the common terminal of the power amplifier input

A customer needs to go back and modify this board to use headphones to listen to music. Remove the amplifier chip (8-pin chip) from the board, and then connect a 104 (or 224) capacitor to the left and right channels of the earphone through the 4th and 6th pins of the main control (which are the left and right channel outputs of the main control chip). The remaining wire is connected from the negative terminal to the common terminal of the earphone

Power on automatic playback

Loop playback with memory function, resume playing from the last played track after next power on

Play Equipped with LED indicator light display

PCB board size 34.23MM (left-right distance) * 22.33MM (up-down distance) * 1mm (thickness)

The maximum size of the appearance is 37.09MM (maximum distance left and right) * 22.33MM (maximum distance up and down) * 2.97MM (maximum thickness)

A 3.7V600MA lithium battery (043545), when fully charged, can be used for approximately 3.5 hours at maximum volume, which is very energy-efficient

Product Introduction

1. Overview

GPD2846A is a chip designed for MP3 players with FM radio and LineIn functions.

2. Main features

Supports MP3 playback format.

Can play T-card/SD card, USB flash drive FM、 External audio source (LineIn), plug in and play first, can also be switched by the Mode key.

Automatically detect whether the headphones are inserted, and based on this, switch the external amplifier directly through the IO port (Mute) without the need for external transistors.

Support storing volume, number of songs, etc. on T-card/SD card, USB flash drive, users can save EEPROM

It can automatically detect whether there is an external EEPROM and decide whether to store the settings in EEPROM or T card/SD card, USB flash drive.

Use one AD key port to achieve various button combinations.

There are two sets of AD key keyboards to choose from.

Supports 3 FM radio chips: RDA5807, BK1080, and RTC6207E.

Does not support infrared remote control.

USB device mode is not supported.

Supports USB audio mode.

Packaging type: SOP16 packaging chip.

3. Product application

MP3 player with FM radio function and screenless mini speaker.

4. Pin definition

Pin # Pin Name Description

1 V33REG DVDD33 digital power supply 3.3V.

2 V50REG VMCU/BAT lithium battery input, 3.3V~5V.

3 VSSREG DVSS digital signal grounding.

4 DACOL DACL left channel audio signal output.

Please install a 1uF capacitor to stabilize the center point of the VCOM Vref audio signal.

6 DACOR DACR right channel audio signal output.

The left and right inputs of 7 LINEN_R LineInR+L LineIn.

8 IOA4 AD key button.

If IOA3 FMCLK has a pull-down resistor to ground, IOA3 will output a clock signal to the outside

Hanging FM radio IC. If IOA3 is suspended, FM receiver IC must

You need to connect a 32768Hz crystal oscillator yourself.

10 IOA2 Mute Mute: Mute external amplifiers.

11 DM DM USB DM.

12 DP DP for USB.

13 IOA0 IO key/LED (1) external LED light: Output "1" represents lighting up the LED.

(2) Also known as IO-key1.

(3) It is also used as a functional option to define key modes.

14 IOB1 SD_CLK

SD_DET

SD_CK: Clock output for T-card/SD card.

SD_DET： Detect if the SD card is inserted, reading '0' indicates insertion.

Please connect a 3.3K Ω resistor to ground.

15 IOB0 SD_CMD

I2C_CLK

SD_CMD: Command and response for T card/SD card.

I2C_CLK: clock of I2C; External EEPROM and FM.

16 IOB2 SD_DAT

I2C_DAT

SD_daT: Data input/output for T card/SD card.

I2C_DAT: I2C data; External EEPROM and FM.

GPD2846

5. AD key button operation function

(5-1) AD key has a total of eight buttons, S1~S8, among which S1~S4 are four buttons that play MP3 mode (i.e. play USB flash drive and...)

The behavior of playing SD card/T card is determined by whether there is an external pull-up resistor on the IOA0/LED pin.

Please pull up to V33REG through a 22K Ω resistor.

We refer to IOA0/LED without Roption as "key mode one" and with Roption as "key mode two".

(5-2) Definition of Key Nouns:

[ Prev ]： Previous， Play the previous MP3.

[ Next ]：Next， Play the next MP3.

[ P/P ]：Play/Pause， Switch between playing and pausing.

[ V+ ]：Volume+， Increase the volume.

[ V++ ]：Volume++， Long pressing will continuously increase the volume until the button is released.

[ V- ]：Volume-， Reduce the volume.

[ V-- ]：Volume--， Long press will continuously decrease the volume until the button is released.

[ Scan ]：Scan ALL FM-band， Automatically search for channels between 87.5MHz and 108.0MHz again, and identify the radio channels with signals

Store it. Up to 50 units can be stored.

[ Scan+ ]： Search for the nearest valid radio station in the direction of 108MHz from the current channel, and then stop playing

This radio station.

[ Scan- ]： Search for channels at 87.5MHz, then move from the current channel to the direction of 87.5MHz to search for the nearest valid radio station, and stop playing

This radio station.

[ CH+ ]： Jump to the next (frequency+) stored FM radio station to play.

[ CH- ]： Jump to the previous (frequency -) stored FM radio station for playback.

[RW]: Rewind, MP3 fast return.

[FF]: Fast Forward, MP3 fast forward.

[Mode]: The order of "Mode switching" is SD card/T card, USB flash drive, FM Line In Loop switching.

If the Mode key is used to switch to the corresponding mode, the playback media in that mode must exist, otherwise it will automatically jump to the next mode

Formula. For example, if the Mode key is used to switch to Line In Mode, the Line In line must be inserted before it will take effect. If it is found that

When not inserted, it will automatically switch to the next mode.

[ Repeat ]： Switch between two loop modes, All? Single (single loop).

[ EQ ]： Sound Field Effects "Normal, Classic, Bass, Live, Rock

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