---

GLAST/LAT > DAQ and FSW > FSW > Doxygen Index > THS / V1-0-5

Constituent: ths     Tag: linux-gcc

---

         

---

THS.h File Reference

Public defs for Time Hack Services. More...

This graph shows which files directly or indirectly include this file:

Typedefs
typedef enum _THS_OPTION	THS_OPTION
	Masks for option mask into THS_init.
typedef unsigned int(	THS_SendSlaveRtn )(void *lsmArg, short lsmID, short thsId, int nid, void *payload, int payloadLen, void *payloadFreeRtn, void *payloadFreeRtnArg)
	stash away routine (from LCM) to send msg to EPU
Enumerations
enum	_THS_OPTION {   THS_GEM_HACK = 1,   THS_CPU_HACK = 2,   THS_SIU_HACK = 4,   THS_GEMPPS_HACK = 8 }
Functions
unsigned int	THS_init (int optionMask)
	Inits the TimeHackService module.
unsigned int	THS_wait ()
	Wait for TimeHackService module to be fully operational.
unsigned int	THS_timetone (unsigned int absTimeSec, unsigned short flags)
	Provide absTime for next entry in table (on next PPS).
WCT_time	THS_gemAbsTimeEvent (int gemStrobeIn, int gemClk)
	Calculate absolute time for event from strobe and clk provided with event (20MHz clk).
unsigned int	THS_cpuSetWarning (unsigned int expectedClkHz, unsigned int expectedDeltaClkHz)
	Set range for cpu clock warning messages.
unsigned int	THS_gemSetWarning (unsigned int expectedClkHz, unsigned int expectedDeltaClkHz)
	Set range for gem clock warning messages.
void	THS_setSlaveSend (THS_SendSlaveRtn rtn, void *arg, int lsmId)
	stash away routine (from LCM) to send msg to EPU
unsigned int	THS_slaveProcessMsg (int func, void *payload, unsigned int len)
	routine called from ITC dispatch in LSM to process each message it receives (this routine is run on EPU when it receives message)

---

Detailed Description

Public defs for Time Hack Services.

Author:

Ed Bacho -- ebacho@slac.stanford.edu

This module handles calculation of absolute time using the "time hack". The absolute (or true) time is provided once a second through a combination of a 1PPS (1 pulse per sec) hardware pulse and a time tone message ("at the tone the time will be") that preceeds it. The time provided in the time tone message from the scapecraft is in microSec since 1/1/2001.

This file has routines for adjusting the time on the CPU clock by using the WCT_set/get routines, therefore one can only get the current time thru WCT_get(). THese are based on a sub-multiple of the CPU's 33 MHz PCI clock.

The determination of the absolute time from event and LCB times is handled in other time hack files.

This module only truely works on the Rad750 which has the PPS input thru the PID registers. The mv2304 version starts up a task to simulate the PPS but it should therefore show no drift (since its locked with the clock)

Inputs:

• time tone message every sec (500-800 mSec before pulse) giving next absTime
• HW 1PPS pulse every sec from GASU (although originates from spacecraft)

Output:

• can obtain corrected absolute time thru WCT_get()

---

Typedef Documentation

void(* THS_SendSlaveRtn)(void *arg, void *payload, int payloadLen)

stash away routine (from LCM) to send msg to EPU Parameters: arg  - given arg to be included with call payload  - buffer with message to send payloadLen  - length of buffer Returns: none This is routine used by THS to send messages between SIU and EPU. It must be passed down from module above that knows how to do this (most likly LSM using ITC calls)

---

Enumeration Type Documentation

enum _THS_OPTION

Enumeration values: THS_GEM_HACK  enable time hack for gem clock (20 MHz) THS_CPU_HACK  enable time hack for cpu clock (33/4 MHz) THS_SIU_HACK  this cpu is the SIU THS_GEMPPS_HACK  setup GEM to produce PPS (valid only on mv2304)

---

Function Documentation

unsigned int THS_cpuSetWarning (  unsigned int  expectedClkHz, unsigned int  expectedDeltaClkHz )

Set range for cpu clock warning messages. Parameters: expectedClkHz  - expected clock in Hz, <=0 uses default, (16.6MHz on mv2304, 8.3MHz on Rad750) expectedDeltaClkHz  - expected delta clk in Hz, <0 uses default of 2% of clock Returns: status

WCT_time THS_gemAbsTimeEvent (  int  gemStrobeIn, int  gemClk )

Calculate absolute time for event from strobe and clk provided with event (20MHz clk). Parameters: gemStrobeIn  stobe counter from GEM from event data gemClk  clk counter from GEM from event data Returns: 64b value of number of nanoSec since 1/1/2001 This routine takes the stobe and clk values from the GEM (part of event data) and converts it to an absolute time. Since this value is calulated through a table saved for the last N secs, it is only valid for the last N secs else will error and retun 0.

Here is the call graph for this function:

unsigned int THS_gemSetWarning (  unsigned int  expectedClkHz, unsigned int  expectedDeltaClkHz )

Set range for gem clock warning messages. Parameters: expectedClkHz  - expected clock in Hz, <=0 uses default of 20MHz expectedDeltaClkHz  - expected delta clk in Hz, <0 uses default of 1% of clock Returns: status

unsigned int THS_init (  int  mask  )

Inits the TimeHackService module. Parameters: mask  time hack options, 1=CPU time hack, 2=Gem Time Hack, 4=CpuIsSiu Returns: status This routine does basic init for THS and requires a few modules to be init (PBS,MSG, ??). It setup the Pid TImers for the PPS interrupt and prepares to handle timeones. Howver, it takes several seconds for time hack to be operational and THS_start() can be used to determine if it is operational.

Here is the call graph for this function:

void THS_setSlaveSend (  THS_SendSlaveRtn  rtn, void *  arg, int  lsmID )

stash away routine (from LCM) to send msg to EPU Parameters: rtn  - pointer to function to use to send off message to EPU arg  - 1st arg passed into rtn lsmID  - 2nd arg passed into rtn Returns: none Given routine should be called as: (rtn)(arg, lsmId, int nid, void *payload, int payloadLen, void* payloadFreeRtn, void *payloadFreeRtnArg);

unsigned int THS_slaveProcessMsg (  int  func, void *  payload, unsigned int  len )

routine called from ITC dispatch in LSM to process each message it receives (this routine is run on EPU when it receives message) Parameters: func  func code for message payload  - buffer with received message len  - length of given buffer Returns: none

Here is the call graph for this function:

unsigned int THS_timetone (  unsigned int  absTimeSec, unsigned short  flags )

Provide absTime for next entry in table (on next PPS). Parameters: absTimeSec  - absolute time for next PPS pulse in secs since 1/1/2001 flags  Returns: status This routine provides the absolute time for next PPS. This should come from the spacecrasft once a sec approx 500-800 milliSec before PPS.

unsigned int THS_wait (   )

Wait for TimeHackService module to be fully operational. Returns: status Since time hack requires a number of subsystems to be operating. These includes LCB driver, 1553 driver, and time tone messages from the scapecraft. Since this module requires two timeTone message from the spacecraft it might take 2 seconds before it is operational. THe routine does a slow poll waiting for the THS to be operational. The sequence is: THS_init(); start up bunch of things including Sw to call THS_timeTone() every second as result of message from spacecraft Hw to cause PPS interrupt every second THS_wait() (this routine waits till receives two THS_timeTone() followed by PPS interrupt)

Here is the call graph for this function:

---