I2C Master Example Code With MCP4725

[rohit_alate]

Hello Team,

I am trying to interface the MCP4725 Module with my S32K148_EVAL Board .for that I am using the ref for the I2C Master Example Code, in the configuration I updated the Device address for the DAC Module 0x60 but it is not able to send the data on the BUS,

Can anyone help me out here with what I am missing here?

Thanks in Advance,
Rohit 

[PetrS]

Hi,

could you please share the connection you have? Do you have pull-ups on I2C lines?
Do you have any scope/analyzer screen of generated frames? Or nothing is seen?

BR, Petr

[rohit_alate]

hi @PetrS ,

NXP -> MCP4725
PTE1 -> SCL

PTC31 ->SDA

J3-13(V5_0) -> VCC

J3-16(GND)->GND

From MCP4725

Out --> +ve scope

Gnd -> -ve scope

No Pullups on I2C Line.

[rohit_alate]

Hello @PetrS ,

I am able to get the Analog data on the scope now, so DAC Interfacing is done.
But a new issue that I am facing is like when I created a different test project and configure the i2c then it will be working fine.

but I have one existing project in that I need to add this so when I am adding the i2c module and the same logic to update the DAC it is going into the Default ISR,

so what could be the reason so I can check on that?

[rohit_alate]

Hello @PetrS ,

I am able to connect the NXPS32K148-EVAL board with MCP4725(12 bit DAC Module).and i am getting analog data as per my inputs.

But the same thing when i try in a loop then it is not giving the analog values based on the input values,

Code : 

void setVoltage(uint16_t output)
{

uint8_t packet[3];

packet[0] = MCP4725_CMD_WRITEDAC;
packet[1] = output / 16; // Upper data bits (D11.D10.D9.D8.D7.D6.D5.D4)
packet[2] = (output % 16) << 4; // Lower data bits (D3.D2.D1.D0.x.x.x.x)

/* Send a packet of data to the bus slave */
LPI2C_DRV_MasterSendDataBlocking(INST_LPI2C1, packet, 3, true, OSIF_WAIT_FOREVER);
}

void delay(int value)
{
while(value--)
{

}
}

int main()

{

.....

for (int i = 0 ; i < 4096 ; i++)
{

setVoltage(1000);
delay(100000);
}

......
}

it will be really helpful if you help me in this,

Thanks,
Rohit

[rohit_alate]

Hello @PetrS ,

its my mistake i assumed it is working but it is still not working ,
PFA :
I2C Configuration :
lpi2c_master_user_config_t lpi2c1_MasterConfig0 = {
.slaveAddress = 98U,
.is10bitAddr = false,
.operatingMode = LPI2C_STANDARD_MODE,
.baudRate = 100000U,
.transferType = LPI2C_USING_INTERRUPTS,
.dmaChannel = 0U,
.masterCallback = NULL,
.callbackParam = NULL,
};

main.c file :
main()

{

LPI2C_DRV_MasterInit(INST_LPI2C1, &lpi2c1_MasterConfig0, &lpi2c1MasterState);

status_t status;
//status = setVoltage(4095);
while(1)
{

status = setVoltage(10);

}

}

it is not able to set the voltage.

[PetrS]

Hi,

please share what is outputted on I2C lines. Does it correspond to the slave device protocol?
What is the value of MCP4725_CMD_WRITEDAC?

BR, Petr

[rohit_alate]

Hello @PetrS ,

The Values :

#define MCP4725_I2CADDR_DEFAULT (0x62) ///< Default i2c address
#define MCP4725_CMD_WRITEDAC (0x40) ///< Writes data to the DAC
#define MCP4725_CMD_WRITEDACEEPROM (0x60) ///< Writes data to the DAC and the EEPROM (persisting the assigned value after reset)

and on pin it is giving the constant 2.57 v as DAC Output to any input Value.

[PetrS]

Hi,

does the DAC acknowledge any byte? You configured slave address 0x62 so you have A0 pin tied to VDD, it that right? Do you really have device with A2:A1 addresses 0:0. As per datasheet this is default factory config, but can be also different, see package marking information.

BR, Petr

[rohit_alate]

Hi @PetrS,

yes, the address of the slave device is 0x60 I updated that one with fast mode configuration,
but still, it is not able to generate the analog signal,

I try to check the DAC module with interfacing with Arduino board and it is working fine with the same logic and all but at NXP side what I am missing not able to get,

PFA for the Zip of the project,

thanks for your quick responses,

Regards,
Rohit