Texas Instruments BOOST-DAC8730-HART, User Manual, Page: 12 / 21

BOOST-DAC8730-HART Software Overview
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12 SLAU699 – May 2017
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BOOST-DAC8730-HART Evaluation Module
The DAC8730 device notifies the microcontroller of a valid HART transaction, and will send this
information to the microcontroller, which in turn will store to a buffer. Pressing the
OK button located under
READ HART reads the byte information from the buffer. This information is displayed in the Status String
indicator field in hexadecimal format.
Pressing the OK button located under Device Status will read the Status Nibble of the DAC8730 device,
which will notify of any errors or flags. This information is displayed in the Status String indicator field in
hexadecimal format and is detailed in Table 7 .
Table 7. UART Command Byte
Code Nibble Status Nibble
DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
See the following table ILOOP_LOW VSHUNT_LOW Don’t Care HL_PWM
Command Code Nibble Reply 2
nd
Byte Description
RESET 0000 PWM A 25-ms timeout has occurred and an updated DAC data is
required. After 10 consecutive RESET commands, a
resynchronization occurs.
IDLE 0010 PWM TX-HART
(optional)
Request for DAC data, no transmitted or received HART data
is required for the bus
START_RX 0100 - - A carrier has been detected, and there is activity on the
HART bus
RX 0101 PWM RX-HART Correct HART data has been received and will be transmitted
in the next byte
RX_PE 1101 PWM RX-HART A parity error has been detected in the HART data. The
received byte will still be transmitted in the next byte.
RX_FE 1110 PWM RX-HART A framing error has been detected in the HART data. The
received byte will still be transmitted in the next byte.
END_RX 0110 PWM - The received HART packet is complete and the bus is no
longer occupied
START_TX 1000 PWM TX-HART
(optional)
HART transmission started and HART data is ready to be
transmitted
TX 1001 PWM TX-HART
(optional)
HART data is still available and the HART packet is still
transmitting
END_TX 1010 PWM - No more HART data is available and the packet is terminated
EXCEPTION 1111 - - Internal state machine error