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Chopperp

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Joined: 03/01/2018
Location: Australia
Posts: 1097

Posted: 11:49pm 16 Jun 2020

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TassyJim said I think the manual is wrong but I will like to see what Brian ends up with before annoying Geoff.
Jim

Hi

Do we want to get the manual changed for this?

Brian

ChopperP

TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 04:44am 17 Jun 2020

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Chopperp said
Do we want to get the manual changed for this?

Brian

It's been done.

Jim

VK7JH
MMedit

TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 08:00am 17 Jun 2020

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If you have a GPS module with a 1 second Pulse, this program will set the CALIBRATE value for you.
It reads the time every minute and every 15 minutes adjusts the RTC CALIBRATE value.

' clock drift test and RTC CALIBRATE setting
' TassyJim June 2020
'
DIM INTEGER calValue = 0 ' initial calibrate vale
DIM GPSint = 38 ' connect to GPS 1pps pulse
DIM interval = 60 ' time between calculations in seconds
DIM adjustTime = 15 ' number of intervals to use for setting RTC CALIBRATE
DIM perDay = 60*60*24/interval ' calculations per day
DIM FLOAT cal = 0.0824 ' secs per day for each unit of RTC CALIBRATE
DIM INTEGER tick, tock, longCount
DIM GPStime$
DIM FLOAT caseTemp
DIM FLOAT RTCtime, lastRTCTime, OSCtime, lastOSCtime, RTCinterval, OSCinterval, OSCerror
DIM FLOAT firstRTC, firstOSC, longRTC, longOSC
DIM FLOAT RTCperDay
DIM INTEGER longTime = LEN(TIME$) ' check to see if MILLISECONDS ON is set"
OPTION milliseconds ON
CLS
INPUT "Starting RTC CALIBRATE value"; calValue
OPTION RTC CALIBRATE calValue
PRINT ""

PRINT "OPTION RTC CALIBRATE is set to ";calValue
PRINT " _______RTC_______ ___8MHz Osc___ Room "
PRINT " Time drift S/Day n Main OSC ppm Temp "

SETPIN GPSint, INTH, GPStick, PULLDOWN
tick = -1
DO
IF tock THEN
doTock
tock = 0
ENDIF
LOOP UNTIL INKEY$ <> "" ' any key to exit
PAUSE 10
IF longTime = 8 THEN ' restore normal TIME$ setting
OPTION milliseconds OFF
PRINT "Time reset to short mode"
ENDIF
PRINT TIME$
PRINT "OPTION RTC CALIBRATE is set to ";calValue

END

SUB GPStick
tick = tick + 1
IF (tick MOD interval) = 0 THEN
tock = 1
GPStime$ = TIME$
OSCtime = TIMER
ENDIF
END SUB

SUB doTock
caseTemp = TEMPR(42)
IF caseTemp > 100 THEN caseTemp = 0
RTCTime = VAL(FIELD$(GPStime$,3,":")) ' only interested in the seconds field
IF tick = 0 THEN
firstRTC = RTCtime
firstOSC = OSCtime
longCount = 0
longRTC = 0
longOSC = 0
RTCinterval = 0
OSCinterval = 0
OSCerror = 0
ELSE
RTCinterval = RTCtime - lastRTCtime
OSCinterval = OSCtime - lastOSCtime
OSCerror = OSCinterval - interval*1000
longCount = longCount + 1
longRTC = (RTCtime - firstRTC)/longCount ' average since program start
longOSC = ((OSCtime - firstOSC)/longCount - interval*1000)*1000/interval ' ppm
ENDIF
RTCperDay = longRTC*perDay
lastRTCtime = RTCtime
lastOSCtime = OSCtime

PRINT GPStime$;" ";STR$(RTCinterval,3,3);" ";STR$(RTCperDay,3,2);" ";
PRINT STR$(-RTCperDay/cal,4,0);" ";STR$(OSCerror,3,3);" ";
PRINT STR$(longOSC,3,3);" ";caseTemp

IF (tick MOD (interval*adjustTime)) = 0 AND tick > 0 THEN ' reset the counter for adjusting
calValue = calValue -RTCperDay/cal
OPTION RTC CALIBRATE calValue
PRINT "New RTC CALIBRATE : ";calValue
tick = -1 ' force reset next tick
ENDIF

END SUB

Starting RTC CALIBRATE value?

OPTION RTC CALIBRATE is set to 0
_______RTC_______ ___8MHz Osc___ Case
Time drift S/Day n Main OSC ppm Temp
17:28:38.374 0.000 0.00 0 0.000 0.000 23.75
17:29:38.367 -0.007 -10.08 122 1.310 21.833 23.5
17:30:38.359 -0.008 -10.80 131 1.322 21.933 23.5
17:31:38.352 -0.007 -10.56 128 1.317 21.939 23.5
17:32:38.345 -0.007 -10.44 127 1.316 21.937 23.5
17:33:38.338 -0.007 -10.37 126 1.318 21.943 23.5
17:34:38.331 -0.007 -10.32 125 1.318 21.947 23.5
17:35:38.324 -0.007 -10.29 125 1.321 21.957 23.5
17:36:38.316 -0.008 -10.44 127 1.318 21.958 23.5
17:37:38.309 -0.007 -10.40 126 1.313 21.950 23.5
17:38:38.302 -0.007 -10.37 126 1.319 21.953 23.5
17:39:38.295 -0.007 -10.34 126 1.323 21.962 23.5
17:40:38.288 -0.007 -10.32 125 1.315 21.958 23.5
17:41:38.281 -0.007 -10.30 125 1.320 21.962 23.5
17:42:38.274 -0.007 -10.29 125 1.318 21.962 23.5
17:43:38.266 -0.008 -10.37 126 1.323 21.968 23.5
New RTC CALIBRATE : 126
17:43:39.266 0.000 0.00 0 0.000 0.000 23.5
17:44:39.266 0.000 0.00 0 1.324 22.067 23.5
17:45:39.266 0.000 0.00 0 1.321 22.042 23.25
17:46:39.266 0.000 0.00 0 1.320 22.028 23.25
17:47:39.266 0.000 0.00 0 1.325 22.042 23.25
17:48:39.266 0.000 0.00 0 1.319 22.030 23.25
17:49:39.266 0.000 0.00 0 1.322 22.031 23.25

columns are
Time
drift in seconds per timing period (60 seconds)
Average drift in seconds per day
Recommended setting for RTC CALIBRATE based on average drift

Main Oscillator error per timing period
Average main osc error in ppm
Case or room temperature (if fitted)

Only need the pps pulse line from the GPS connected.

Jim

VK7JH
MMedit

Chopperp

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Joined: 03/01/2018
Location: Australia
Posts: 1097

Posted: 11:58am 17 Jun 2020

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Gee thanks Jim.

I will need to modify my GPS module to get a 1 sec pulse out.

It has a 1 sec flashing LED on board so it shouldn't be too hard to do.

For interest, I just had a play with modifying
"open "com4:9600" as GPS,10"
on an F4 hoping to have an INT routine triggered I.E
"open "com4:9600, 2, Test_GPS, 2" as gps,10 "
but the INT routine was ignored.

BTW, is there, or do you have an MMEdit version/update for the CMM2?

Brian

ChopperP

matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 10315

Posted: 03:50pm 17 Jun 2020

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Quote In my days, even with precision xtal clocked Micros, you still had to code critical u-sec timing tasks in assembler,

The CMM2 firmware sets up a 32-bit timer to increment 240,000,000 times per second. This happens in the background irrespective of any CPU activity. �The main timing uSec routine is then

#define SetupTime 22
#define ticks_per_microsecond 240
void uSec(unsigned int us) {
�us=us*ticks_per_microsecond-SetupTime;
�WriteCoreTimer(0);
�while (ReadCoreTimer()<us);
}

SetupTime is a fudge factor which I tuned as part of the development that counteracts the number of cycles needed to enter, setup the timer and leave the subroutine.

I also use another timer which is setup to clock at 20MHz for things like WS2812 timings. The STM32H743 has lots of timers

Edited 2020-06-18 01:51 by matherp

TassyJim

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Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 09:54pm 17 Jun 2020

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Chopperp said
BTW, is there, or do you have an MMEdit version/update for the CMM2?

Brian

You need to go to version 4x for the CMM2.
I am still finding keywords that I missed but most of them are there.
I have changed the way keywords are stored to make it easier to keep up with the multitude of systems out there.

Jim

VK7JH
MMedit

Chopperp

Guru

Joined: 03/01/2018
Location: Australia
Posts: 1097

Posted: 10:25pm 17 Jun 2020

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Thanks Jim

Just downloaded it. I see CMM2. Will try ii out later today.

Must remember to give you some beer money as well.....

Brian

ChopperP

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