RTOS/SIMPLELINK-MSP432-SDK: No function similar to UARTCharAvail present in TIVA driver library for MSP432

Thank you Bob for your input.

I will try this out and get back to you.

Regards,

Vikram 

Hi Bob,

I tried to use the concept for the demo uart code but did not find any difference in the outcome so will it be possible for you to please explain what is the difference in using the UART_RETURN_NEWLINE v/s UART_RETURN_FULL;

The source that I will be getting data from is a black box to me as we don't have access to it in terms of what sort of data will it be sending.

The task is that there is a pulser which triggers through a watchdog event on MSP432 and starts sending data over its uart line to the MSP432. So we are not sure whether it sends a new line character everytime or not?

Thank you

Vikram

Vikram,
Unless the device at the other end explicitly sens a Newline, you may not see one. The UART_RETURN_NEWLINE /FULL parameters determine when the given thread unblocks or returns. So either a newline or a buff-full condition unblocks the READ command in that thread.

As I understand this, you have just 1 MSP432 device communicating with something else, and you are using an input pulse from that other device to trigger a watchdog timer on the MSP432 (exactly why you're using a watchdog instead of just allowing the external pulse to trigger an interrupt isn't clear). After this pulse, you are receiving a constant stream of data for some time and you want to ensure that you don't get a buffer overflow. Thus you are checking the buffer (originally using UARTCharsAvail(uint32_tBase)) periodically to process that data.

Is that an accurate description of what you are trying to do? And if so, is there a reason you are not using the UART read command and allowing it to unblock/return when the given buffer is full? I would think that would perform the same operation described above.

Regard,s
Bob

Hi Bob,

Thank you for your reply.

Yes, I have just one MSP432 device that communicates with the other device (micro pulser) over the UART.  The concept of watchdog is not triggered by the other device instead the watchdog is triggered at a fixed time interval in MSP432 and post this watchdog triggered event, I turn on the other device and send some command in reply to which the other device starts sending stream of data for some time. 

So I want to ensure I don't get the buffer overflow error and since, I have to use the ring buffer to constantly collect the data received I also don't want to miss out on the data received.

I am using the UART_read command but the problem is at times, I still run into the buffer overflow error.

So if there is a function similar to UARTCharsAvail, I can use that to verify after certain fixed data value if something else is left to be received or not.

Thank you

Vikram

Vikram,

  Determining the righ approach here will requre knowing a little about the incoming datastream, but here are a few things to consider:

1. The UART driver APIs have the options  when opening/initiatlizing (UART_params_init() ) a UART instance

• UART_DATA_TEXT- treats all device line endings a a newline
• UART_RETURN_NEWLINE - causes UARTread() to return when seeing a newline instead of when buffer is full
• You could use the 2 options above to minimize the chance you'll overrun your buffer

2. You could alternately use UART_readPolling(), which won't return until it has read <size> number of bytes. How you use this and the size to set depends on your incoming data. Again, if <size> is much less than your buffer size, then you reduce the chance of overunning your buffer.

Regards,

  Bob

Thank you Bob,

Much appreciated on the 3 points you mentioned. I will try with Option 1 since I cannot use the UART_readPolling() function.
Hope to get the best result.

Regards,
Vikram