200 lines
4.6 KiB
C
200 lines
4.6 KiB
C
/*
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* ALDL Dashboard, core 160 baud handling code
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*
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* (c) 2019 Solomon Peachy <pizza@shaftnet.org>
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*
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* The latest version of this program can be found at:
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*
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* http://git.shaftnet.org/cgit/users/pizza/public/aldl_pi.git
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 3 of the License, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* [http://www.gnu.org/licenses/gpl-3.0.html]
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*
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* SPDX-License-Identifier: GPL-3.0+
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*
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*/
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#include <stdio.h>
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#include <stdint.h>
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#include <time.h>
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#include <unistd.h>
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#include <pthread.h>
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#include "aldl.h"
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/* shift register & sync word */
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#define SYNC_WORD 0x1ff
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#define DWELL_TIME 1000 /* microseconds after falling edge */
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#define DEBOUNCE_TIME 200 /* microseconds */
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#define MAX_STREAM_WORDS 255
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static uint16_t ALDLSR = 0;
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static uint8_t bits = 0;
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static int datalen = 0;
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static uint8_t data[MAX_STREAM_WORDS];
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int gotsync = 0;
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static FILE *datalog_handle;
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struct stream_common decoded = { 0 };
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void (*aldl_callback)(uint8_t *data, int datalen) = NULL;
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/* Datalogging */
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void datalog_init(char *fname)
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{
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datalog_handle = fopen(fname, "a");
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if (!datalog_handle)
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perror("Can't open datalog file!\n");
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fprintf(datalog_handle, "# New session\n");
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}
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void datalog_close(void)
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{
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if (datalog_handle)
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fclose(datalog_handle);
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}
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static void aldl_datalog(uint8_t *data, int datalen)
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{
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int i;
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if (!datalog_handle) return;
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fprintf(datalog_handle, "%ld", time(NULL));
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for (i = 0 ; i < datalen ; i++) {
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fprintf(datalog_handle, ",%02x", *data++);
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}
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fprintf(datalog_handle, "\n");
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}
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static void process_bit(int val)
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{
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ALDLSR <<= 1;
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ALDLSR |= (val & 1);
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if ((ALDLSR & SYNC_WORD) == SYNC_WORD) {
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/* New sync word, we've finished a sequence */
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printf(" - %d\n", datalen);
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/* Received a sync word.. */
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ALDLSR = 0;
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if (!gotsync) {
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gotsync = 1;
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return; /* First one, we don't do anything */
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}
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/* Process ALDL payload */
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if (aldl_callback)
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aldl_callback(data, datalen);
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/* Log data */
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if (datalog_handle)
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aldl_datalog(data, datalen);
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/* Reset state */
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bits = 0;
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datalen = 0;
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} else if (++bits == 9) {
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printf(" %02x", ALDLSR & 0xFF);
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/* Just latch in the word */
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data[datalen++] = ALDLSR & 0xff;
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/* Reset state */
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bits = 0;
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ALDLSR = 0;
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}
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}
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/* ISR */
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void isrfn(void)
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{
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int val;
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delayfn(DWELL_TIME); // To handle both variations, minimum of 0.5, max of 1.8ms
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val = !readbit(); // If hi, represents ALDL 0; if low, ALDL1.
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process_bit(val);
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}
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#include <sys/time.h>
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int run_sampler = 1;
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long tv_diff(struct timeval *tv1, struct timeval *tv2)
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{
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long usecs = (tv2->tv_sec - tv1->tv_sec) * 1000000;
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usecs += (tv2->tv_usec - tv1->tv_usec);
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return usecs;
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}
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/* Alternatively.. continually poll. */
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void poll_gpio(void)
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{
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struct timeval tv, last_tv;
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int pin, last_pin;
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long total_us = 0;
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gettimeofday(&last_tv, NULL);
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last_pin = readbit();
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while(run_sampler) {
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/* Read */
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gettimeofday(&tv, NULL);
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pin = readbit();
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/* Work out how long it's been since our last sample */
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total_us += tv_diff(&last_tv, &tv);
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last_tv = tv;
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/* No edge.. or possibly false edge. */
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if (pin == last_pin || total_us < DEBOUNCE_TIME)
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continue;
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if (pin == 1) { /* ie Rising edge */
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// printf ("%06d\n", total_us);
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/* Rising edge. tells us when the bit ends */
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if (total_us > DWELL_TIME)
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process_bit(0); /* long period high is logical 0 */
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else
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process_bit(1); /* short period high is logical 1 */
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}
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/* Edge transition, reset time and record new pin */
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total_us = 0;
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last_pin = pin;
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}
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}
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static pthread_t poller;
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static int polling = 0;
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static void *thread_poller(void *arg)
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{
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poll_gpio();
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pthread_exit(NULL);
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}
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int thread_start(void)
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{
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polling = 1;
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return pthread_create(&poller, NULL, thread_poller, NULL);
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}
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void thread_shutdown(void)
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{
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if (polling) {
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run_sampler = 0;
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pthread_join(poller, NULL);
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polling = 0;
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}
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}
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