+++ /dev/null
-/******************************************************************************
- *
- * Trennfix firmware - mm_switch.c
- *
- * Maerklin Motorola switch command receiver
- *
- * Copyright (C) 2017 Philipp Hachtmann
- *
- * 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/>.
- *
- *****************************************************************************/
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include <avr/io.h>
-#include <avr/eeprom.h>
-#include <avr/interrupt.h>
-#include <avr/pgmspace.h>
-
-#include <util/delay.h>
-#include <stdint.h>
-
-#include "hardware.h"
-#include "mm_switch.h"
-
-// #define DEBUG_TIMEOUT
-#ifdef DEBUG_TIMEOUT
-#define MON(val) setpin(PIN_DRIVE, val)
-#else
-#define MON(xx) ({0;})
-#endif
-
-
-/*
- * Lookup decoder number.
- *
- */
-
-static uint8_t lookup_nibble(uint8_t mm_nibble)
-{
- switch(mm_nibble) {
- case 0x0: return 0;
- case 0xc: return 1;
- case 0x8: return 2;
- case 0x3: return 3;
- case 0xf: return 4;
- case 0xb: return 5;
- case 0x2: return 6;
- case 0xe: return 7;
- case 0xa: return 8;
- default: return 0;
- }
- return 0;
-}
-
-static uint8_t lookup_decoder(uint8_t mm_byte)
-{
- uint8_t low;
- uint8_t high;
- if (mm_byte == 0)
- return 100;
- low = lookup_nibble(mm_byte >> 4);
- high = lookup_nibble(mm_byte & 0xf);
- if (!low)
- return 0;
- return 9 * high + low;
-}
-
-static uint8_t lookup_command(uint8_t mm_byte)
-{
- switch(mm_byte) {
- case 0xc3: return 1;
- case 0x03: return 2;
- case 0xf3: return 3;
- case 0x33: return 4;
- case 0xcf: return 5;
- case 0x0f: return 6;
- case 0xff: return 7;
- case 0x3f: return 8;
- default:
- return 0;
- }
-}
-
-
-static __attribute__((unused)) void mm_switch_init(void)
-{
- /* Get rid of the 1/8 clock prescaler */
- CLKPR = (1 << CLKPCE);
- CLKPR = 0;
-
- GIMSK |= _BV(PCIE); /* Enable pin change interrupt */
- PCMSK = _BV(PCINT4); /* PB4, Rail sense input */
-
- TCCR0A = 0; /* This is normal mode */
- TCCR0B = 0; /* Timer off */
- TIMSK |= _BV(OCIE0A); /* Get a match interrupt */
- TIMSK |= _BV(TOV0); /* Overflow interrupt */
-
- /* We need 13 + 45 us delay, That's 464 clocks @8MHz*/
- OCR0A = 91; /* Prescaler 8 is used */
-
- /* Timer 1 for timeout */
- /* We set it to 1024us by prescaler 64 and running full 256 */
- TCCR1 = 7;
- TIMSK |= _BV(TOIE1); /* Overflow interrupt */
-}
-
-static volatile uint8_t shift_command;
-static volatile uint8_t shift_function;
-static volatile uint8_t shift_address;
-static volatile uint8_t shift_command_first;
-static volatile uint8_t shift_address_first;
-
-/* We will shift from right to left.
- * XXXXXXXX XX XXXXXXXX
- * shift_address shift_function shift_command
- *
- * The bits 7 downto 2 of shift_function are ignored.
- */
-
-volatile uint8_t bitno = 0;
-
-static void __attribute__((unused)) trigger(void)
-{
- setpin(PIN_DRIVE, 1);
- _delay_us(4);
- setpin(PIN_DRIVE, 0);
- _delay_us(4);
-}
-
-enum recstate {
- IDLE = 0,
- FIRST_FAST_SAMPLE,
- FIRST_SLOW_SAMPLE, /* If clock arrives, we stay on the fast path! */
- FAST_SAMPLE,
- FAST_WAIT_FOR_CLOCK,
- SLOW_SAMPLE,
- SLOW_WAIT_FOR_CLOCK,
-};
-
-static enum recstate recstate = IDLE;
-
-static inline void shift(uint8_t value)
-{
- shift_address <<= 1;
- if (shift_function & 2)
- shift_address |= 1;
- shift_function <<= 1;
- if (shift_command & 0x80)
- shift_function |= 1;
- shift_command <<= 1;
- if (value)
- shift_command |= 1;
-}
-
-
-ISR(TIMER0_COMPA_vect) {
- static uint8_t patience = 0;
- static uint8_t address_last = 0xff;
- static uint8_t function_last = 0xff;
- static uint8_t command_last = 0xff;
-
- switch(recstate) {
- case FIRST_FAST_SAMPLE:
- recstate = FIRST_SLOW_SAMPLE;
- TSTART_CLK_TO_SAMPLE_FAST; /* Will not run out in fast! */
- break;
-
- case FIRST_SLOW_SAMPLE:
- bitno = 0;
-
- case SLOW_SAMPLE:
- recstate = SLOW_WAIT_FOR_CLOCK;
- TSTART_CLK_TO_SAMPLE_SLOW;
- break;
-
- case FAST_SAMPLE:
- recstate = FAST_WAIT_FOR_CLOCK;
- TSTART_CLK_TO_SAMPLE_FAST;
- break;
-
- case FAST_WAIT_FOR_CLOCK: /* A timeout! */
- if (patience) {
- patience--;
- TSTART_CLK_TO_SAMPLE_FAST;
- return;
- }
- recstate = IDLE;
- TSTOP;
- return;
-
- case SLOW_WAIT_FOR_CLOCK:
- if (patience) {
- patience--;
- TSTART_CLK_TO_SAMPLE_SLOW;
- return;
- }
- default:
- TSTOP;
- recstate = IDLE;
- return;
- }
-
- shift(MM_SENSE);
- bitno++;
-
- if (bitno == 18) { /* Save first received word */
- shift_command_first = shift_command;
- shift_address_first = shift_address;
- patience = 18;
-
- }
-
- if (bitno == 36) {
- if ((shift_command == shift_command_first) &&
- (shift_address == shift_address_first)) {
- if ((shift_address != address_last) || (shift_command != command_last) ||
- shift_function != function_last) {
-
- uint8_t addr = lookup_decoder(shift_address);
-
- if (recstate == SLOW_WAIT_FOR_CLOCK) {
- mm_switch_drive(addr, shift_function, shift_command);
- }
-
-
- if (recstate == FAST_WAIT_FOR_CLOCK && addr) {
- uint8_t command = lookup_command(shift_command);
- /* Congratulations, we have a valid command */
- mm_switch_command(addr, command);
- }
- }
- address_last = shift_address;
- function_last = shift_function;
- command_last = shift_command;
- }
-
- }
-}
-
-//void __attribute((weak)) mm_switch_drive(uint8_t address, uint8_t function, uint8_t command);
-
-ISR(BADISR_vect)
-{
- while(1) {
- /*
- setpin(PIN_LED, 1);
- _delay_ms(30);
- setpin(PIN_LED, 0);
- _delay_ms(30);
- setpin(PIN_LED, 1);
- _delay_ms(30);
- setpin(PIN_LED, 0);
- _delay_ms(2000);
- */
- }
-}
-
-ISR(TIM0_OVF_vect)
-{
- return;
- while(1) {
- setpin(PIN_LED, 1);
- _delay_ms(30);
- setpin(PIN_LED, 0);
- _delay_ms(300);
- }
-
-}
-
-
-/* Pin change interrupt vector */
-void mm_pinchange_handler(void)
-{
- static uint8_t sense_last;
-
- if (MM_SENSE == sense_last)
- return;
- sense_last = MM_SENSE;
- if (!sense_last)
- return;
-
- switch(recstate) {
- case IDLE:
- bitno = 0;
- recstate = FIRST_FAST_SAMPLE;
- TSTART_CLK_TO_SAMPLE_FAST;
- break;
- case FIRST_SLOW_SAMPLE:
- recstate = FAST_SAMPLE;
- TSTART_CLK_TO_SAMPLE_FAST;
- break;
- case FAST_WAIT_FOR_CLOCK:
- recstate = FAST_SAMPLE;
- TSTART_CLK_TO_SAMPLE_FAST;
- break;
- case SLOW_WAIT_FOR_CLOCK:
- recstate = SLOW_SAMPLE;
- TSTART_CLK_TO_SAMPLE_SLOW;
- break;
-
- /* Not expected */
- case FIRST_FAST_SAMPLE:
- case FAST_SAMPLE:
- case SLOW_SAMPLE:
- default:
- break;
- }
-}
-
-/******************************************************************************
- * The end :-)
- */
-
-
-
projects / eisenbahn.git / blobdiff