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PGA460-Q1: PGA460 comm interface minimum requirements

Matias Fineschi
Intellectual 340 points
Part Number: PGA460-Q1
Other Parts Discussed in Thread: PGA460,

Hello everyone on this forum.

I have 2 questions regarding the PGA460:

1) Is the device operable only using the UART? In other words, are all the comm interfaces independent? This questions relies on the fact that when  a burst & listem command ends (executed on the Data Monitor view of the GUI ) I see some activity on the IO pin.

I'm designing my custom application using the PGA460-Q1 and just wanted to confirm that the device is fully usable through the UART interface only (either sincronic or asincronic). I have limited space and only able to use the UART. What I've read so far tells me that this is posible, but I'm asking just in case I'm missing anything.

2) Related to the previous question. What are the minimum requirements regarding its comms interfaces for the PGA460?

3) The S-to_M DAta Bytes section of the GUI only shows 54 bytes when executing  a "transducer echo data dump" command. Isn't this command supposed to output 128 bytes? Is this a bug on the GUI software?

Thank you :).

Cheers,

  • 0
    TI__Mastermind 27780 points
    Hi Matias,

    1) The PGA460 can be operated completely/independently in the following comm interface modes:
    •Asynchronous UART
    •Synchronous UART
    •One-Wire UART
    •Time Command Interface
    so, yes, the device can be fully operated in the UART mode. The IO pin can be floating if not used. The SCLK pin should be pulled to GND via a 10kOhm resistor if not used. There should not be any activity on the IO pin when using UART mode. Is the activity you are monitoring only present on the EVM when using the GUI? Have you checked if the IO pin toggles using custom software and/or hardware?

    2) To use the asynchronous UART mode, refer to the 7.5.1 UART and USART Communication Examples on page 55 of the PGA460-Q1 datasheet. Be sure your master MCU is using the PGA460 required UART frame structure:
    •8 data bits
    •1 start bit
    •2 stop bit
    •No parity bit
    •No flow control
    •Interfield wait time (only required when using 1 stop bit)
    Note: Most MCU's default to 1 stop bit, so ensure you have configured your master's UART port for 2 stop bits.
    The PGA460 supports an asynchronous baud rate between 2.4k to 115.2kBaud.

    3) Yes, the transducer echo data dump command is 128 bytes. The GUI's S-to-M Data Bytes section only shows up to 54 bytes at a time. If you were to were to click the "Send & Receive Bytes" button twice more, you'd see the other thirds of the data. It's less of a GUI bug, and more of a lack of explanation and limitation of the USB2ANY-per-transaction data packet size of 54 bytes. The MSP430 UART buffer actually captures the entire 128 byte readout locally, which is why when you read the buffer more than once, you eventually pull all the data (in segments).