diff options
| author | Keith Packard <keithp@keithp.com> | 2012-09-09 13:50:56 -0700 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2012-09-09 13:50:56 -0700 |
| commit | 3fa71c497a5bf576974e70af06762f75734e6699 (patch) | |
| tree | e2e2e5ce5881db1a8262b979fea456f8fc9d808d /src | |
| parent | 27ab744c6eec9243b7aa14161eec2fbf7003531e (diff) | |
altos: Try to get remote cmac time closer to reality
Record the time after the packet was sent, but before the return
packet arrives to try and more closely approximate the time the packet
arrived at the other end.
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/drivers/ao_lco_func.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/src/drivers/ao_lco_func.c b/src/drivers/ao_lco_func.c index 152b5d1b..99e58b76 100644 --- a/src/drivers/ao_lco_func.c +++ b/src/drivers/ao_lco_func.c @@ -28,18 +28,18 @@ ao_lco_query(uint16_t box, struct ao_pad_query *query, uint16_t *tick_offset) { uint8_t i; int8_t r; - uint16_t time; + uint16_t sent_time; ao_mutex_get(&ao_lco_mutex); - time = ao_time(); - command.tick = time; + command.tick = ao_time() - *tick_offset; command.box = box; command.cmd = AO_LAUNCH_QUERY; command.channels = 0; ao_radio_cmac_send(&command, sizeof (command)); - r = ao_radio_cmac_recv(query, sizeof (*query), AO_MS_TO_TICKS(500)); + sent_time = ao_time(); + r = ao_radio_cmac_recv(query, sizeof (*query), AO_MS_TO_TICKS(20)); if (r == AO_RADIO_CMAC_OK) - *tick_offset = time - query->tick; + *tick_offset = sent_time - query->tick; ao_mutex_put(&ao_lco_mutex); return r; } |