• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 1 answer
  • Subscribers 80 subscribers
  • Views 583 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MSP430FR50431: Implementing millis() function

Jan Malcák
Prodigy 40 points
Part Number: MSP430FR50431

Hi guys,

I am trying to implement millis() function from Arduino. What it does, it counts number of milliseconds since the program started and returns it. 

What I have so far is a Timer A3, sourced from SMCLK in UP mode: Gist. (for some reason, I was unable to insert code directly here).

The problem is, that for some reason, after 5-6 uart messages, the program halts and no other millis() update is sent to the uart. 

I don't know, if that is UART problem, or it has something to do with the millis implementation. But I spent two last days looking into it, following tutorials online and nothing helped. Clearly, I need second pair of eyes.

Would you please be so kind to look at the code and point to some parts, which could be wrong? Thank you in advance.

  • 0
    Guru 41995 points

    What type is your millis variable?

    I assume you have it volatile.

  • 0 in reply to Keith Barkley
    Prodigy 40 points

    Yes, its volatile, defined on the first line of linked gist.

    static volatile uint32_t TIMER_MS_COUNT = 0;
  • +1
    Guru 95935 points

    1) This

    EUSCI_A_UART_enableInterrupt(EUSCI_A2_BASE, EUSCI_A_UART_TRANSMIT_COMPLETE_INTERRUPT); // void

    enables UCTXCPTIE, but I don't see an ISR, so as soon as you get a UCTXCPTIFG you will end up in ISR_trap. Just remove this line. (I'm a bit surprised you ran as long as you did, given Erratum USCI42.)

    2) I don't see uart_write. I do see something called ss_uart_write.

    3) Check your stack size -- CCS's default is usually rather small. sprintf uses maybe 200 bytes of stack, along with texty[200].
  • 0 in reply to Bruce McKenney
    Prodigy 40 points

    Ad1) Yes, it was the line enabling interruptions. I used to have an ISR in there, just to set uart_busy flag in uart_write(), but later on I decided to rather wait for UCTXCPTIFG flag. Thank you so much!

    ad2) ss_uart_write() should be named uart_write(), its just a relic of me copying and editing the code for the publication.

    ad3) According to this thread, stack size should not be limited (except the total stack size). So I have to check current stack pointer and compare it to stack end, to make sure my program does not run out of memory? 

  • 0 in reply to Jan Malcák
    Guru 95935 points

    3) By "check" I just meant go to "Build Settings->Build->Linker->Basic->Set C Stack Size" and see if that value is even vaguely reasonable. I tossed out (200+200) as a possible estimate; alternatively, just add 200 (for text[]) to whatever's there.

  • 0 in reply to Bruce McKenney
    Prodigy 40 points

    Thank you, it was set to 160. I'll increase it.

**Attention** This is a public forum