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Add CRC16 with reverse bit order

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This commit is contained in:
Nils Faerber 2011-07-19 12:31:32 +02:00
parent 5c3d6461a1
commit 0d6cba4530
5 changed files with 450 additions and 4 deletions
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73
metawatch.c
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@ -7,23 +7,90 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>
#include "metawatch_protocol.h"
#include "crc16ccitt.h"
void dump_frame(unsigned char *frame, int len)
{
int i;
for (i=0; i<len; i++)
fprintf(stderr, "0x%02x ", frame[i]);
fprintf(stderr, "\n");
}
void mw_send_packet(int mw_fd, unsigned char msg_type, unsigned char options, unsigned char *data, unsigned char len)
{
unsigned short crc;
unsigned char frame[64];
memset(frame, 0, 64);
frame[0] = MW_SOF;
frame[1] = len + 6;
frame[2] = msg_type;
frame[3] = options;
memcpy(frame+4, data, len);
crc = crc16ccitt(frame, len+4);
*(unsigned short *)(frame+len+4) = crc;
dump_frame(frame, len+6);
write(mw_fd, frame, len+6);
}
void mw_set_rtc(int mw_fd, unsigned char clk1224, unsigned char date_fmt)
{
time_t mtime;
struct tm mtm;
unsigned short year;
unsigned char data[32];
mtime = time(NULL);
localtime_r(&mtime, &mtm);
year = mtm.tm_year + 1900;
data[0] = (year & 0x0f00) >> 8;
data[1] = (year & 0x00ff);
data[2] = mtm.tm_mon + 1;
data[3] = mtm.tm_mday;
data[4] = mtm.tm_wday;
data[5] = mtm.tm_hour;
data[6] = mtm.tm_min;
data[7] = mtm.tm_sec;
data[8] = clk1224;
data[9] = date_fmt;
mw_send_packet(mw_fd, MW_SET_REAL_TIME_CLOCK, 0, data, 10);
}
int main(int argc, char **argv)
{
int mwfd;
int mw_fd;
if (argc != 2) {
fprintf(stderr, "Usage:\n\t%s <devicename>\n", argv[0]);
return 1;
};
mwfd = open(argv[1], O_RDWR);
if (mwfd < 0) {
crc16ccitt_init();
mw_fd = open(argv[1], O_RDWR);
if (mw_fd < 0) {
perror("open");
return 1;
};
mw_set_rtc(mw_fd, MW_RTC_CLOCK_24HR, MW_RTC_DATE_DDMM);
fsync(mw_fd);
close(mw_fd);
return 0;
};