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Launchpad midi synth

Larry Frazier
Prodigy 90 points


Hello. I'm trying to get midi in via USART on a g2553 Launchpad. I seem to be getting 0x80, note off, but not note on. I've tried various baud/oversample settings to see if I'm just getting garbage, but I keep getting note off vs. nothing. I have a buffer for RXD input, so I hope data isn't still getting overwritten.

I'm a noob, sorry if there's just something simple I don't get.

void uart_init(void)
{
    uart_set_rx_isr_ptr(0L);

    P1SEL  = RXD + TXD;                       
      P1SEL2 = RXD + TXD;                       
      UCA0CTL1 |= UCSSEL_2 + ~UC7BIT;                     // SMCLK==4mhz
      UCA0BR0 = 32;                            //  DIVIDES SMCLK BY 32*16 = 31250  = MIDI SPEC w/UCOS16 oversample
      UCA0BR1 = 0;                              //
      UCA0MCTL =  ~UCBRS0 + UCOS16;// + ~UC7BIT ;                        // Modulation UCBRSx = 1
      UCA0CTL1 &= ~UCSWRST + ~UCMSB;                     // Initialize USCI state machine
      IE2 |= UCA0RXIE;                          // Enable USCI_A0 RX interrupt
}

thanks

  • 0
    Guru 58965 points

    Let's do a little "math".

    Do you know what is : 0x00 | (0x80 + ~0x10) ?

    ~0x10 is 0x7F

    (0x80 + 0x7F) is 0xFF

    0x00 | (0xFF) is 0xFF

    Do you want to chage UCA0CTL1 to 0xFF?

    You have: UCA0CTL1 |= UCSSEL_2 + ~UC7BIT; 



  • 0 in reply to old_cow_yellow
    Prodigy 90 points

    Ok, I see that error. I fixed that, but I still don't see the remaining prob. Been trying to tweak things and getting a little lost...

    void uart_init(void)
    {
        uart_set_rx_isr_ptr(0L);

        P1SEL  = RXD + TXD;                       
          P1SEL2 = RXD + TXD;                       
          UCA0CTL1 |= UCSSEL_2;                     // SMCLK==4mhz
          UCA0BR0 = 8;                            //  DIVIDES SMCLK  = 31250  = MIDI SPEC w/UCOS16 oversample
          UCA0BR1 = 0;                              //
          UCA0MCTL =   UCBRS0 + UCOS16;// + ~UC7BIT ;                        // Modulation UCBRSx = 1
          UCA0CTL1 &= ~UCSWRST;// + ~UCMSB;                     // Initialize USCI state machine
          IE2 |= UCA0RXIE;                          // Enable USCI_A0 RX interrupt
    }

  • 0 in reply to Larry Frazier
    Prodigy 90 points

    I had the clock divider wrong also, fixed above. midi CC and note on going thru now....thx!

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