DAC81416EVM: DAC Configuration & DAC Out

Dear Akhilesh,

Please find the attached Graphs

Read Register:

Write Register:

Hi Madhusudan,

Thanks for the scope image but still CS signal missing in your capture. DAC code will update  rising edge of CS signal. 

Also, SYNC-EN bit must set to 0.

Please share SPI capture with CS signal and ensure SYNC-EN bit set to 0.

Dear Anbu Mani35,

Please find the Attached Graphs

Clock and CS:

MOSI and CS:

So, I am trying to read Device ID and Version. But MISO signal is disturbed.

Here code:

void dac_init(void)

{

GPIO_WritePin(DAC_RESETn, CLEAR);
/* Delay for a bit */
DELAY_US(1000); // 1msec
GPIO_WritePin(DAC_RESETn, SET);

}

void loop(void)

{

dacWrite_Version(0x8100);         // Status

}

Hi,

I believe you have two issue right ? 

1.  Device ID is not able to read

2.  DAC output not updating  

1st will discuss about Device ID read issue then later discuss about DAC output update.

You mentioned that MISO signal get disturbed , meaning are you getting something not valid data at MISO ?  your captured image not showing MISO data. could you please share(CS,CLK,SDI, SDO) on signal screen. if you are suing 2ch scope 

share SPI code of read device ID, what sequence are you following ?  did you enable SDO -EN bit at register 03

Read device ID required 2 SPI cycles, 1s read command(write cycle), 2nd data read (read cycle)- refer Fig7-2   

Hello,

Please find the attached Signals and Code

Mode configured with Polarity: 0, Phase: 1

void inti(void)

{

GPIO_WritePin(DAC_RESETn, CLEAR);
/* Delay for a bit */
DELAY_US(1000);// 1msec
GPIO_WritePin(DAC_RESETn, SET);
/* Power-up device */
dac_init_steps(0x030004);

}

void loop(void)

{

dacWrite_Version(0x010000); // Status
dacWrite_Version(0x810000); // Status

}

Trying to read Device ID and Version.

CLK and CS

MOSI: CLK and Data

MISO: CLK and Data

Hi ,

Could you please try is sequence and probe MISO.

void loop(void)

{

dacWrite_Version(0x810000); // Status
dacWrite_Version(0x810000); // Status 

}

Not getting MISO data.

Please any once share Devise ID and Version reference code.

I am trying to Read Devise ID and Version getting problem.

I am using EVM as it is. Just interface SPI signals CS, MISO, MOSI, SCLK, Reset, along with voltages

I, J2 header pins shorted is it okay?

Giving input supplies 

J7.3 ---- GND

J7.4-----VIO-----5V

J7.5-----VDD/VAA-----5V

J7.6 -----VSS-------GND

J7.7-------VCC------30V

Note: LDAC and CLR not used.

Thank you Advance.

J2 header must be open

J3 header must be open

J2 header mush be open, if shorted device in reset state.

Devise ID and Version reading done.

Actually In TMS320f28379 EVM, SPI configuration as Polarity:0 Phase:1 working.

Can you share example code for DAC out.

Thank you.

Hello.

I am trying to post on dac value. But not getting.

Added Prepared code.

void Dac_init(void)

{

GPIO_WritePin(DAC_RESETn, CLEAR);
/* Delay for a bit */
DELAY_US(1000);//delay(1);//~1mse
GPIO_WritePin(DAC_RESETn, SET);

//Configuration

/* DACRANGEn Register A Range: +/- 20V */
dac_init_steps(0x0acccc); 
/* DACRANGEn Register B Range: +/- 20V */
dac_init_steps(0x0bcccc); 
dac_init_steps(0); /*Receive bytes */
/* DACRANGEn Register C Range: +/- 20V */
dac_init_steps(0x0ccccc); 
/* DACRANGEn Register D Range: +/- 20V */
dac_init_steps(0x0dcccc); 
/* Power-up device */
dac_init_steps(0x030a84);

/* Power up all channels */
dac_init_steps(0x090000);

/* Enable Broadcast for all channels */
dac_init_steps(0x05ffff);
/* Write code to all channels */
dac_init_steps(0x0fffff);

}

void loop(void)

{

dacWrite(0x107fff);

DELAY_US(100);

dacWrite(0x10ffff);

DELAY_US(100);

}

Thank you,

Hi ,

Good to hear that can fix code read issue . 

I have couple of questions here.

1.  I can understand that  you are  using TMS320f28379 EVM as host controller for SPI interface right ? 

2.  Before going directly update DAC , i want to ensure you cable able to write the register without any issue? did you checked both read /write happening ? 

Say for example , write a 0xAA55 data to register 0x05 address and read back your getting 0xAA55.

0x05 -> 0xAA55 ; Write 

0x05 -> < read data > ; should be 0xAA55.

Hello,

1. Host is TMS320f28379  EVM

2.Read and write is done.

I am trying to post on dac value. But not getting.

Hi,

I see from you setup VCC = 30 and VSS = 0V , DAC output voltage can be done uni-polar. 

void Dac_init(void)

{

GPIO_WritePin(DAC_RESETn, CLEAR);

/* Delay for a bit */

DELAY_US(1000);//delay(1);//~1mse

GPIO_WritePin(DAC_RESETn, SET);

//Configuration

/* DACRANGEn Register A Range: 0- 20V */ // updated as per your reference 30 V on VCC

dac_init_steps(0x0a2222);      

/* DACRANGEn Register B Range: 0- 20V */ updated as per your reference 30 V on VCC

dac_init_steps(0x0b2222); 

/* DACRANGEn Register C Range:0-20V */ updated as per your reference 30 V on VCC

dac_init_steps(0x0c2222); 

/* DACRANGEn Register D Range: 0- 20V */ updated as per your reference 30 V on VCC

dac_init_steps(0x0d2222); 

/* Power-up device */

dac_init_steps(0x030a84);   //

dac_init_steps(0x060000);   //  Add this line here DAC update with Async Mode

/* Power up all channels */

dac_init_steps(0x090000); //

/* Enable Broadcast for all channels */

dac_init_steps(0x05ffff);  // Brd cast enabled of all channed

/* Write code to all channels */

dac_init_steps(0x0f8000);    // Write DAC code to update all DAC for 10V  

}

Try this code , it will update all 16 channels.

Hello,

Thank you for your Support.

Shall we get Positive and Negative(Ex:+/-10) voltage on Single DAC out pin?

If possible how to Configure Registers.

Please Suggest me

Thank you Advance...

Yes , do the following to get +/-10V output.

Giving input supplies 

J7.3 ---- GND

J7.4-----VIO-----5V

J7.5-----VDD/VAA-----5V

J7.6 -----VSS >  - 10V

J7.7-------VCC> + 10V

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

void Dac_init(void)

{

GPIO_WritePin(DAC_RESETn, CLEAR);

/* Delay for a bit */

DELAY_US(1000);//delay(1);//~1mse

GPIO_WritePin(DAC_RESETn, SET);

//Configuration

/* DACRANGEn Register A Range:+/-10V */ // VCC= +10V, VSS = -10V

dac_init_steps(0x0aaaaa);      

/* DACRANGEn Register B Range: +/-10V */VCC= +10V, VSS = -10V

dac_init_steps(0x0baaaa); 

/* DACRANGEn Register C Range:+/-10V */ VCC= +10V, VSS = -10V

dac_init_steps(0x0caaaa); 

/* DACRANGEn Register D Range: +/-10V */ VCC= +10V, VSS = -10V

dac_init_steps(0x0daaaa); 

/* Power-up device */

dac_init_steps(0x030a84);   //

dac_init_steps(0x060000);   //  Add this line here DAC update with Async Mode

/* Power up all channels */

dac_init_steps(0x090000); //

/* Enable Broadcast for all channels */

dac_init_steps(0x05ffff);  // Brd cast enabled of all channed

/* Write code to all channels */

dac_init_steps(0x0f8000);    // Write DAC code to update all DAC for 10V  

}

Hope this code will help to drive +/10V output.