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phc2sys: improve servo start up

master
Miroslav Lichvar 2012-08-30 19:44:37 +02:00 committed by Richard Cochran
parent 41ffd8dfb8
commit bf21c7c6a9
1 changed files with 7 additions and 8 deletions
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15
phc2sys.c
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@ -122,7 +122,8 @@ static int read_phc(clockid_t clkid, clockid_t sysclk, int rdelay, int64_t *offs
} }
struct servo { struct servo {
uint64_t last_ts; uint64_t saved_ts;
int64_t saved_offset;
double drift; double drift;
enum { enum {
SAMPLE_0, SAMPLE_1, SAMPLE_2, SAMPLE_3, SAMPLE_N SAMPLE_0, SAMPLE_1, SAMPLE_2, SAMPLE_3, SAMPLE_N
@ -136,7 +137,6 @@ static void do_servo(struct servo *srv,
int64_t offset, uint64_t ts, double kp, double ki) int64_t offset, uint64_t ts, double kp, double ki)
{ {
double ki_term, ppb; double ki_term, ppb;
int64_t delta;
printf("s%d %lld.%09llu drift %.2f\n", printf("s%d %lld.%09llu drift %.2f\n",
srv->state, ts / NS_PER_SEC, ts % NS_PER_SEC, srv->drift); srv->state, ts / NS_PER_SEC, ts % NS_PER_SEC, srv->drift);
@ -144,19 +144,20 @@ static void do_servo(struct servo *srv,
switch (srv->state) { switch (srv->state) {
case SAMPLE_0: case SAMPLE_0:
clock_ppb(dst, 0.0); clock_ppb(dst, 0.0);
srv->saved_offset = offset;
srv->saved_ts = ts;
srv->state = SAMPLE_1; srv->state = SAMPLE_1;
break; break;
case SAMPLE_1: case SAMPLE_1:
srv->state = SAMPLE_2; srv->state = SAMPLE_2;
break; break;
case SAMPLE_2: case SAMPLE_2:
delta = ts - srv->last_ts;
offset = delta - NS_PER_SEC;
srv->drift = offset;
clock_ppb(dst, -offset);
srv->state = SAMPLE_3; srv->state = SAMPLE_3;
break; break;
case SAMPLE_3: case SAMPLE_3:
srv->drift = (offset - srv->saved_offset) * 1e9 /
(ts - srv->saved_ts);
clock_ppb(dst, -srv->drift);
clock_step(dst, -offset); clock_step(dst, -offset);
srv->state = SAMPLE_N; srv->state = SAMPLE_N;
break; break;
@ -173,8 +174,6 @@ static void do_servo(struct servo *srv,
clock_ppb(dst, -ppb); clock_ppb(dst, -ppb);
break; break;
} }
srv->last_ts = ts;
} }
static int read_pps(int fd, int64_t *offset, uint64_t *ts) static int read_pps(int fd, int64_t *offset, uint64_t *ts)