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ethercat
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Improved DC tome offset calculation: 

- Only write time offset, if absolute difference to application time is
      more than 100 ms.
    - Separate handling for 32 bit and 64 bit time registers.
This commit is contained in:
Florian Pose 2010-03-29 18:04:17 +02:00
parent a79d5e0329
commit 1aa6122534
2 changed files with 107 additions and 10 deletions
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1
TODO
View File

@ -52,7 +52,6 @@ Future issues:
* Override sync manager size?
* Show Record / Array / List type of SDOs.
* Distributed clocks:
- Check 32/64 bit operations.
- Use vendor correction factors when calculating transmission delays.
- Skip setting system time offset when application detached.
- How to use the SYNC1 shift time?

116
master/fsm_slave_config.c
View File

@ -44,6 +44,12 @@
/*****************************************************************************/
/** Time difference [ns] to tolerate without setting a new system time offset.
*/
#define EC_SYSTEM_TIME_TOLERANCE_NS 100000000
/*****************************************************************************/
void ec_fsm_slave_config_state_start(ec_fsm_slave_config_t *);
void ec_fsm_slave_config_state_init(ec_fsm_slave_config_t *);
void ec_fsm_slave_config_state_clear_fmmus(ec_fsm_slave_config_t *);
@ -400,7 +406,9 @@ void ec_fsm_slave_config_state_dc_clear_assign(
ec_datagram_print_wc_error(datagram);
}
// read DC system time and system time offset
// read DC system time (0x0910, 64 bit)
// gap (64 bit)
// and time offset (0x0920, 64 bit)
ec_datagram_fprd(fsm->datagram, fsm->slave->station_address, 0x0910, 24);
fsm->retries = EC_FSM_RETRIES;
fsm->state = ec_fsm_slave_config_state_dc_read_offset;
@ -408,6 +416,93 @@ void ec_fsm_slave_config_state_dc_clear_assign(
/*****************************************************************************/
#define ABS(X) ((X) >= 0 ? (X) : -(X))
/** Configure 32 bit time offset.
*/
u64 ec_fsm_slave_config_dc_offset32(
ec_fsm_slave_config_t *fsm, /**< slave state machine */
u64 system_time, /**< System time register. */
u64 old_offset, /**< Time offset register. */
unsigned long jiffies_since_read /**< Jiffies for correction. */
)
{
ec_slave_t *slave = fsm->slave;
u32 correction, system_time32, old_offset32, new_offset;
s32 time_diff;
system_time32 = (u32) system_time;
old_offset32 = (u32) old_offset;
// correct read system time by elapsed time since read operation
correction = jiffies_since_read * 1000 / HZ * 1000000;
system_time32 += correction;
time_diff = (u32) slave->master->app_time - system_time32;
if (slave->master->debug_level)
EC_DBG("Slave %u: system_time=%u (corrected with %u),"
" app_time=%u, diff=%i\n",
slave->ring_position, system_time32, correction,
(u32) slave->master->app_time, time_diff);
if (ABS(time_diff) > EC_SYSTEM_TIME_TOLERANCE_NS) {
new_offset = time_diff + old_offset32;
if (slave->master->debug_level)
EC_DBG("Slave %u: Setting time offset to %u (was %u)\n",
slave->ring_position, new_offset, old_offset32);
return (u64) new_offset;
} else {
if (slave->master->debug_level)
EC_DBG("Slave %u: Not touching time offset.\n",
slave->ring_position);
return old_offset;
}
}
/*****************************************************************************/
/** Configure 64 bit time offset.
*/
u64 ec_fsm_slave_config_dc_offset64(
ec_fsm_slave_config_t *fsm, /**< slave state machine */
u64 system_time, /**< System time register. */
u64 old_offset, /**< Time offset register. */
unsigned long jiffies_since_read /**< Jiffies for correction. */
)
{
ec_slave_t *slave = fsm->slave;
u64 new_offset, correction;
s64 time_diff;
// correct read system time by elapsed time since read operation
correction = (u64) (jiffies_since_read * 1000 / HZ) * 1000000;
system_time += correction;
time_diff = fsm->slave->master->app_time - system_time;
if (slave->master->debug_level)
EC_DBG("Slave %u: system_time=%llu (corrected with %llu),"
" app_time=%llu, diff=%lli\n",
slave->ring_position, system_time, correction,
slave->master->app_time, time_diff);
if (ABS(time_diff) > EC_SYSTEM_TIME_TOLERANCE_NS) {
new_offset = time_diff + old_offset;
if (slave->master->debug_level)
EC_DBG("Slave %u: Setting time offset to %llu (was %llu)\n",
slave->ring_position, new_offset, old_offset);
} else {
new_offset = old_offset;
if (slave->master->debug_level)
EC_DBG("Slave %u: Not touching time offset.\n",
slave->ring_position);
}
return new_offset;
}
/*****************************************************************************/
/** Slave configuration state: DC READ OFFSET.
*/
void ec_fsm_slave_config_state_dc_read_offset(
@ -417,6 +512,7 @@ void ec_fsm_slave_config_state_dc_read_offset(
ec_datagram_t *datagram = fsm->datagram;
ec_slave_t *slave = fsm->slave;
u64 system_time, old_offset, new_offset;
unsigned long jiffies_since_read;
if (datagram->state == EC_DATAGRAM_TIMED_OUT && fsm->retries--)
return;
@ -438,15 +534,17 @@ void ec_fsm_slave_config_state_dc_read_offset(
return;
}
system_time = EC_READ_U64(datagram->data);
old_offset = EC_READ_U64(datagram->data + 16);
new_offset = slave->master->app_time - system_time + old_offset;
system_time = EC_READ_U64(datagram->data); // 0x0910
old_offset = EC_READ_U64(datagram->data + 16); // 0x0920
jiffies_since_read = jiffies - datagram->jiffies_sent;
if (slave->master->debug_level)
EC_DBG("Slave %u: DC system_time=%llu old_offset=%llu, "
"app_time=%llu, new_offset=%llu\n",
slave->ring_position, system_time, old_offset,
slave->master->app_time, new_offset);
if (slave->base_dc_range == EC_DC_32) {
new_offset = ec_fsm_slave_config_dc_offset32(fsm,
system_time, old_offset, jiffies_since_read);
} else {
new_offset = ec_fsm_slave_config_dc_offset64(fsm,
system_time, old_offset, jiffies_since_read);
}
// set DC system time offset and transmission delay
ec_datagram_fpwr(datagram, slave->station_address, 0x0920, 12);