//
// BlimpBot
// CSE 466 final project
// Josh Green, Baron Oldenburg, Henry Baba-Weiss
//
#include <string.h>
#include "bsp.h"
#include "virtual_com_cmds.h"

// Specialized version of the normal COM_Init function that is tweaked to work
// with the MSP430f5510 on the blimps.
void COM_Init()
{
  //................
  UCSCTL3 = SELREF_2;                       // Set DCO FLL reference = REFO
  UCSCTL4 |= SELA_2;                        // Set ACLK = REFO
  UCSCTL0 = 0x0000;                         // Set lowest possible DCOx, MODx

  // Loop until XT1,XT2 & DCO stabilizes - In this case only DCO has to stabilize
  do
  {
    UCSCTL7 &= ~(XT2OFFG + XT1LFOFFG + DCOFFG);
                                            // Clear XT2,XT1,DCO fault flags
    SFRIFG1 &= ~OFIFG;                      // Clear fault flags
  } while (SFRIFG1&OFIFG);                  // Test oscillator fault flag

  __bis_SR_register(SCG0);                  // Disable the FLL control loop
  UCSCTL1 = DCORSEL_5;                      // Select DCO range 16MHz operation
  UCSCTL2 |= 255;                           // Set DCO Multiplier for 8MHz
                                            // (N + 1) * FLLRef = Fdco
                                            // (249 + 1) * 32768 = 8MHz
  __bic_SR_register(SCG0);                  // Enable the FLL control loop

  // Worst-case settling time for the DCO when the DCO range bits have been
  // changed is n x 32 x 32 x f_MCLK / f_FLL_reference. See UCS chapter in 5xx
  // UG for optimization.
  // 32 x 32 x 8 MHz / 32,768 Hz = 250000 = MCLK cycles for DCO to settle
  __delay_cycles(250000);

  P4SEL = BIT4+BIT5;                        // P3.4,5 = USCI_A0 TXD/RXD
  UCA1CTL1 |= UCSWRST;                      // **Put state machine in reset**
  UCA1CTL1 |= UCSSEL__SMCLK;                // CLK = SMCLK
  UCA1BR0 = 54;                             //
  UCA1BR1 = 0;                              //
  UCA1MCTL = UCBRS_0 + UCBRF_10 + UCOS16;   // Modulation UCBRSx=0, UCBRFx=10
  UCA1CTL1 &= ~UCSWRST;                     // **Initialize USCI state machine**
  UCA1IE |= UCRXIE;                         // Enable USCI_A0 RX interrupt
}

// Transfers the given string over the UCSI UART port. Uses explicit length, instead 
// of looking for a null byte to terminate the string.
void TXString(char* string, int length)
{
  int pointer;
  for( pointer = 0; pointer < length; pointer++)
  {
    UCA1TXBUF = string[pointer];
    while (!(UCA1IFG & UCTXIFG));              // USCI_A0 TX buffer ready?
  }
}