a NOOB question, please help

[fouadalnoor]

Hello, I am trying to make a simple mp3 player using:

-MCU (with integrated Decoder)
-DAC (With integrated Amplifier)
-6 Buttons
- LCD Screen
-SD card

I have the data sheets for all the components I need, but I am new at this and I am having problems drawing the circuit for it. What I want to do now is just write a list of all the pins and how they connect together using the data sheets.

I have now made the following list:

MCU to

DAC - pin 56 (DOUT), pin 57 (DCLK), pin 58 (DSEL), pin 59 (SCLK)

MCU to buttons

[1] Volume Up - pin 3 (P0.5/AD5)

[2] Volume Down - pin 4 (P0.4/AD4)

[3] Play/pause - pin 5 (P0.3/AD3)

[4] Previous - pin 6 (P0.2/AD2)

[5] Next - pin 7 (P0.1/AD1)

[6] Menu - pin 8 (P0.0/AD0)

MCU to

LCD - pin 84 (P0.6/AD6)


I now from this list what pins I have to use from my MCU, but I dont know where these pins connect to my DAC. I have looked at all the data sheets and cant seem to figure out what pins from the DAC connect to the pins from my MCU...


I usually dont like asking for help since its an indipendent project, but now I am just lost.

I was hoping that someone here could tell me where each pin from the MCU connects to which pin from the DAC. (Also please explain to me why you have chosen to connect a perticular pin to another pin so that I can learn)

Any help will be GREATLY APPRICIATED!

Yours truly fouadalnoor

 

[arunb]

The DAC uses a SPI port. It seems the MCU too has a SPI port, but I think it is meant for a SD card.

For the SPI Port

DAC MCU

CS (Chip Select) An general I/O port (Output)
SDI (Serial Data In) MOSI (Output)
SCLK (Serial Clock) SCK (Output)
Mode Any General I/O (output)

Chip Select pins makes the device ready for SPI access, SDI pin is used to clock in the data, SCLK is the clock pin (this goes high and low for each bit of the data)

Mode ??? (see the datasheet)

Read the DAC and the MCU datasheets very carefully, keep in mind the control voltage for these devices, if the devices use different voltages, level shifters may be needed.

See the SPI timing diagrams, these will show the states of the various pins of the SPI at any given time.

Do the same for the LCD. This has a parallel interface.

Construct the project stagewise, start by interfacing the mcu with DAC. You should develop driver procedures/functions that can read/write to the DAC.

Once you have done this, start by interfacing the mcu with the LCD. Here again develop driver code for controlling the device.

After all this read the datasheet (see examples) to see how the MP3 decoder works.

You should start the actual project only after you have solved the interface problems individually.

hope this helps

thanks
a