DAC8741H: HART Data framing

mukesh Prajapati

Part Number: DAC8741H

Hello,

Suppose I want send one byte data(ex. 0x02) to HART sensor, so I am writing 0x02 byte to LSB of FIFO_D2M_Register and its odd parity bit writing
in to bit-8 of FIFO_D2M_Register.

As per HART protocol, suppose if want to send one byte data (ex. 0x02) then it expect as "Start bit | 8-bit data | parity bit | stop bit".

Please let me know where to configure start bit and stop bit. I do not found any description related to start bit and stop bit in DAC8741H data sheet.

Please clarify me as we are working with HART interface in delay.

Thanks,
Mukesh Prajapati

over 5 years ago

0 Paul_Frost over 5 years ago

TI__Guru 53773 points

Hi Mukesh,

As you are using the SPI input version of the device, the DAC8741H automatically implements the start bit, parity, and stop bit. The start, parity, and stop bits are defined by the HART standard, which this device is compliant with.

Thanks,
Paul

0 mukesh Prajapati over 5 years ago in reply to Paul_Frost

Prodigy 110 points

Hi Paul,

I want to confirm one thing from you is if it add start bit and stop bit that is fine. but what about bit-8 of FIFO_D2M_Register.

Whether we need to write odd parity bit of data byte in it or not?

Please clarify.

Thanks,

Mukesh Prajapati.

0 Paul_Frost over 5 years ago in reply to mukesh Prajapati

TI__Guru 53773 points

Hi Mukesh,

You do not need to add the parity bit. The device will calculate it for you.

Thanks,

Paul

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DAC8741H: HART Data framing