/*
    Copyright 2017 fishpepper <AT> gmail.com

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http:// www.gnu.org/licenses/>.

   author: fishpepper <AT> gmail.com
*/

#include "hal_ppm.h"
#include "ppm.h"

#ifndef SBUS_ENABLED

void hal_ppm_init(void) {
    // no int on overflow:
    OVFIM = 0;

    // set channels to compare interupt:
    // CH0: off
    T1CCTL0 = 0;
    // CH1: off
    T1CCTL1 = 0;
    // CH2: toggle pin on cmp match, will generate sync pulses
    #if PPM_INVERTED
    // inverted, set on match, clear on zero
    T1CCTL2 = T1CCTLx_MODE_COMPARE | T1CCTLx_CMP_SETCLR0;
    #else
    // non-inverted, clear on match, set on zero
    T1CCTL2 = T1CCTLx_MODE_COMPARE | T1CCTLx_CMP_CLRSET0;
    #endif  // PPM_INVERTED

    // configure peripheral alternative1 for timer 1:
    // use alt config 1 -> clr flag -> P0_4 = output
    PERCFG &= ~(PERCFG_T1CFG);

    // USART1 use ALT2 in order to free up P0_4 for peripheral func
    PERCFG |= PERCFG_U1CFG;

    // select P0_4 for peripheral function
    // NOTE: make sure to set usart1 to alt2 config!
    P0SEL |= (1 << PPM_OUT_PIN);

    // select P0_4 as output
    P0DIR |= (1 << PPM_OUT_PIN);

    // prescaler = 128
    // tickspeed = 26MHz / 8 = 3,25MHz (TICKSPD is set in timeout.c!)
    // 1us = 3.25 ticks -> 2ms = 6500 ticks, 4ms = 13000
    T1CTL = T1CTL_MODE_MODULO | T1CTL_DIV_1;


    // ch2 cmp: sync pulse length
    SET_WORD_LO_FIRST(T1CC2H, T1CC2L, PPM_SYNC_PULS_LEN_TICKS);

    // overflow:
    SET_WORD_LO_FIRST(T1CC0H, T1CC0L, HAL_PPM_US_TO_TICKCOUNT(1000));

    ppm_output_index = 0;

    // clear pending interrupt flags (IRCON is reset by hw)
    T1CTL &= ~(T1CTL_CH0_IF | T1CTL_CH1_IF | T1CTL_CH2_IF | T1CTL_OVFIF);

    // overflow causes an int -> reload next channel data
    OVFIM = 1;

    // enable T1 interrups
    T1IE = 1;
}


void hal_ppm_failsafe_exit() {
    // configure p0_4 as peripheral:
    P0SEL |= (1<<4);

    // reset counter:
    SET_WORD_LO_FIRST(T1CNTH, T1CNTL, 0);

    // re enable timer interrupts:
    OVFIM = 1;

    // disable T1 interrups
    T1IE = 1;
}

void hal_ppm_failsafe_enter(void) {
    // disable interrupts
    OVFIM = 0;

    // disable T1 interrups
    T1IE = 0;

    // configure p0_4 as normal i/o:
    P0SEL &= ~(1<<4);

    // set pins to failsafe level:
    #if PPM_INVERTED
    // clear on zero -> default is high
    P0 |= (1<<4);
    #else
    // set on zero -> default is low
    P0 &= ~(1<<4);
    #endif  // PPM_INVERTED
}

#endif  // SBUS_ENABLED