#include <msp430.h>
#include "SPI.h"

uchar SPI_CS;

int SPIInit(){

  UCA0CTL1 = UCSWRST;

  // setup A0 for SPI
  UCA0CTL0 = SPI_Mode3 | UCMSB | UCMST | (0x10 << 1) | UCSYNC;
  UCA0CTL1 |= UCSSEL_2;
  UCA0BR1 = 0; //TODO: set corect frequency
  UCA0BR0 = 4;


  // config port
  //set SEL to USCI (0b01); MOSI (pin 1), MISO (pin 2), CLK (pin 4)
  P1SEL  |= BIT1 | BIT2 | BIT4;
  P1SEL2 |= BIT1 | BIT2 | BIT4;


  UCA0CTL1 &= ~UCSWRST;

  // enable interrupts
  IE2 |= UCA0TXIE;
  IFG2 &= ~UCA0TXIFG;

  // set initial values for vars
  SPI_packetC = 0;
  SPI_CS = 0;

  __enable_interrupt();

  return 0;
}

void SPISend(){
  P1OUT &= ~SPI_CS;
  UCA0TXBUF = SPI_packet[SPI_packetC];
}

void SPIInitSend(uchar cs, enum SPI_Mode mode){
  while(SPI_CS != 0)
      //TODO: search for a more power effient way for a delay
      __delay_cycles (16000);

  UCA0CTL0 |= mode;
  UCA0CTL0 &= ~mode ^ 0xC0;
  SPI_CS = cs;
}

#pragma vector = USCIAB0TX_VECTOR
__interrupt void ISR_EUSCI_A0(){
  SPI_packet[SPI_packetC] = UCA0RXIFG;
  if(SPI_packetC == 4){
    P1OUT |= SPI_CS;
    SPI_packetC = 0;
    IFG2 &= ~UCA0TXIFG;
    SPI_CS = 0;
  }else{
    SPI_packetC++;
    UCA0TXBUF = SPI_packet[SPI_packetC];
  }
}