DAC8741H: What is sequence for send command and get response

mukesh Prajapati

Part Number: DAC8741H

Hello,

I am able to write FIFO_D2M Register and read FIFO_M2D Register. It is working fine.

But want to confirm bytes which I am writing in to FIFO_D2M Register. so sets DUP_EN bit of MODEM_Control register to 1.

Allocated TX FIFO and RX FIFO size to 16.

Then,

Writing 15 bytes in to FIFO_D2M Register,

Activating modulator.

Waiting for 2 Seconds.

Activating demodulator.

Reading FIFO_D2M register 15 times

But I am not receiving bytes which I have transmitted and getting HART gap error and parity error in MODEM_STATUS Register.

Can you please suggest.

Is there any sample code please let me know.

Thanks,

Mukesh Prajapati.

over 5 years ago

0 Paul_Frost over 5 years ago

TI__Guru 53773 points

Hi Mukesh,

My understanding is that for the full-duplex mode to work you will need to have both the modulator and demodulator active at the same time. Please try that.

Thanks,

Paul

0 mukesh Prajapati over 5 years ago in reply to Paul_Frost

Prodigy 110 points

Hello,

DAC8741H do not allow modulator and de-modulator to be active at same time.

Please let me know how to avoid gap error and parity error which I am getting while transmitting data bytes.

Thanks,

Mukesh Prajapati

0 Paul_Frost over 5 years ago in reply to mukesh Prajapati

TI__Guru 53773 points

Hi Mukesh, I am checking with my design team to confirm this.

0 Paul_Frost over 5 years ago in reply to Paul_Frost

TI__Guru 53773 points

Hi Mukesh,

In this use case, you should activate both the modulator and the demodulator at the same time. In the provided sequence, by the time the demodulator is enabled the data put into the Tx FIFO has already been sent, and there is nothing to demodulate.

In normal operation, only one function can operate at a time, thus half-duplex mode. When the full-duplex mode is enabled then the demodulator will see the data the modulator transmits.

Thanks,

Paul

0 mukesh Prajapati over 5 years ago in reply to Paul_Frost

Prodigy 110 points

Hi,

Please update on above for how to resolve gap error and parity error which I am getting while transmitting a data irrespective of half duplex or full duplex mode.

Thanks,

Mukesh Prajapati.

0 Paul_Frost over 5 years ago in reply to mukesh Prajapati

TI__Guru 53773 points

Hi Mukesh,

Are you measuring this on the EVM, or custom hardware? Can you share your schematic?

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DAC8741H: What is sequence for send command and get response