MSP430FR2355: SLAA458 PULSE OXIMETER WITH MSP430FR2355

Hello All,

Iam trying to design a pulse oximeter using MSP430FR2355 Launchpad. I've been able to successfully use the SAC module and get the SPO2 raw data from the SAC . I have also used ADC to read the SAC output and convert to digital form. Iam following SLAA458 & SLAA897 TI Documents. Can anybody tell me what is the meaning of the below shown code. This code is picked up from SLAA458 . 

 /* Track the beating of the heart */
        heart_signal_sample_counter++;
        if (pos_edge)
        {
            if (edge_debounce < 120)
            {
                edge_debounce++;
            }
            else
            {
                if (ir_heart_ac_signal < -200)
                {
                    edge_debounce = 0;
                    pos_edge = 0;
                    display_pulse(0);
                }
            }
        }
        else
        {
            if (edge_debounce < 120)
            {
                edge_debounce++;
            }
            else
            {
                if (ir_heart_ac_signal > 200)
                {
                    edge_debounce = 0;
                    pos_edge = 1;
                    display_pulse(1);
                    display_correcting(1, 0);
                    if (++heart_beat_counter >= 3)
                    {
                        log_heart_signal_sample_counter = heart_signal_sample_counter;
                        log_sq_ir_heart_ac_signal = sq_ir_heart_ac_signal;
                        log_sq_vs_heart_ac_signal = sq_vs_heart_ac_signal;
                        heart_signal_sample_counter = 0;
                        sq_ir_heart_ac_signal = 0;
                        sq_vs_heart_ac_signal = 0;
                        heart_beat_counter = 0;
                        _BIC_SR_IRQ(LPM0_bits);
                                            // Do a dummy wake up roughly
                                            // every 2 seconds
                    }
                }
            }
        }

 what is meaning of edgebounce , pos edge, and 

ir_heart_ac_signal >200 or

ir_heart_ac_signal < -200 ?

 
My other question is regarding UART of the MCU.
 Is There any way to use printf command to send data over UART with a newline ending . It is easy to send data using newline & print f as I do not have to break the data into MSB  & LSB.

Currently Iam using

while(!(UCA1IFG & UCTXIFG));
UCA1TXBUF = data ; // LSB OF DATA

I mean I've been using TIVA C series MCU'S and UART communication in them is pretty easy to use.