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Forum Index : Microcontroller and PC projects : CMM - replacing 1307 with 3231 RTC
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| viscomjim Guru  Joined: 08/01/2014 Location: United StatesPosts: 925 |
Now I get it. In the routine settime, you are calculating the dow from the date$ and sending it to the ds3231 to set it initially. Sorry for my confusion. I makes perfect sense now. Real nice routine!!!! |
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| twofingers Guru Joined: 02/06/2014 Location: GermanyPosts: 1133 |
Hi all! I think this is could be wrong: Dow=(day+y+Int(y/4)-Int(y/400)+Int(31*m/12)) Mod 7 I use TZAdvantage's DOW Calculation like this: Dow=(day+y+Int(y/4)-Int(y/100)+Int(y/400)+Int(31*m/12)) Mod 7 Sunday = 0. I use some modification of jman's code för my DS3231SN/24C32 modul. Works perfectly (nearly)! Before that I used some DS1307 and PCF8563's. I dont like them anymore. The DS3231/24C32 modul takes less then 100nA (Battery mode), costs (on eBay from china-dealer) less then 1,4 EUR and includes a 4K eeprom + a CR2032! 'Jman's code for the DS3231
'No alarms or offset 'Calculation to set Day of the week 'SETTIME from the console will set the DS3231 with the current 'time and date ' I2C RTC based On DS1307 Secs,Mins,Hours,Day,Date,Month,Year,Control 'DayOfWeek() corrected + some small optical improvements 10-8-2014 Option base 0 Dim RTCbuff(7) Dim TempBuff(2) Dim Days$(7) For I = 0 To 6 Read Days$(I) Next I Data "Sunday" Data "Monday" Data "Tuesday" Data "Wednesday" Data "Thursday" Data "Friday" Data "Saturday" '********************* ' Start Mainloop '********************* Do ReadTime 'from DS3231 ReadTemp 'from DS3231 Cls Print "Time has been set to ";Time$ Print"Date has been set to ";Date$ Print "Today is ";Days$(DayOfWeek()) Print "Temperature is";Temperature-2.25 'brute force correction Pause 1000 Loop End '********************* ' End Mainloop '********************* '********************* Sub ReadTime 'from DS3231 I2C '********************* i2caddr = &h68 ' DS3231 I2C address I2C open 100,100 ' Enable I2C I2C write I2caddr, 0, 1, 0 I2C Read i2caddr, 0, 7, RTCbuff(0) ' Read Time I2C Close sec$ = Str$(BCDtoDec(RTCBuff(0))) min$ = Str$(BCDtoDec(RTCBuff(1))) hours$ = Str$(BCDtoDec(RTCBuff(2))) DOW$ = Str$(BCDtoDec(RTCBuff(3))) 'day of week?? always=0? day$ = Str$(BCDtoDec(RTCBuff(4))) month$ = Str$(BCDtoDec(RTCBuff(5))) year$ = Str$(BCDtoDec(RTCBuff(6)) + 2000 ) t$ = hours$+":"+min$+":"+sec$ D$ = day$+"/"+month$+"/"+year$ Time$ = T$ Date$ = D$ End Sub '********************* Sub ReadTemp ' read temperature from DS3231 I2C '********************* i2caddr = &h68 ' DS3231 I2C address I2C open 100,100 ' Enable I2C I2C write I2caddr, 0, 1, 17 I2C Read i2caddr, 0, 2, TempBuff(0) ' Read Temperature I2C Close If Tempbuff(0) < &h80 Then Temperature= TempBuff(0) + (TempBuff(1) / 256) Else Temperature = -((TempBuff(0) Xor &HFF) + 1) + (TempBuff(1) / 256)) EndIf End Sub '********************* Sub SetTime ' Get time from time$ and date$ '********************* hours = BCDtoHex(Val(Left$(Time$, 2))) minutes = BCDtoHex(Val(Mid$(Time$, 4, 2))) seconds = BCDtoHex(Val(Right$(Time$, 2))) day = BCDtoHex(Val(Left$(Date$, 2))) month = BCDtoHex(Val(Mid$(Date$, 4, 2))) year = BCDtoHex((Val(Right$(Date$, 4)) - 2000)) ' Write Time to RTC i2caddr = &h68 ' DS3231 I2C address I2C Open 100,100 ' Enable I2C I2C Write i2caddr,0,8,0,seconds,minutes,hours,dow,day,month,year I2C Close Print "0=ok 1=nack 2=timeout"; MM.I2C If MM.I2C=0 Then Print "RTC has been set to ";Time$;" ";Date$ Else Print "Error!" End Sub '********************* 'Calculate Day Of Week TZAdvantage's DOW Calculation '********************* Function DayOfWeek a = Int((14-Val(Mid$(Date$,4,2)))/12) m = Val(Mid$(Date$,4,2)) + 12*a - 2 y = Val(Mid$(Date$,7,4)) -a day = Val(Mid$(Date$,1,2)) DayOfWeek = (day+y+Int(y/4)-Int(y/100)+Int(y/400)+Int(31*m/12)) Mod 7 End Function '********************* ' Convert to Hex '********************* Function BCDtoHex (TempDec) BCDtoHex = Fix(tempdec / 10) * 16 BCDtoHex = BCDtoHex Or ((tempdec / 10) - (Fix(tempdec / 10))) * 10 End Function '********************* ' Convert to Decimal '********************* Function BCDtoDec (BCDTEMP) BCDtoDec = Fix(BCDTemp / 16) * 10 BCDtoDec = BCDtoDec + (BCDTEMP And &hF) End Function With respect to Jman. I hope, it's okay to post it here? Michael |
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| viscomjim Guru Joined: 08/01/2014 Location: United StatesPosts: 925 |
Hi Two Fingers, I noticed that when you are reading the register for dow that you commented 'day of week?? always=0?. I think that once you set that register correctly, that it will change accordingly and stay correct. Have you tried that yet? As far as your calculation for dow, I can't check right now, but I have been using this for a while and has been working properly for me. I will use yours to check when I get home. I used to live in Hanover as a child. Not so young anymore and live in Florida USA. Where are you? |
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| twofingers Guru Joined: 02/06/2014 Location: GermanyPosts: 1133 |
Hi viscomjim, I don't use the DS3221 registers for 'day of week' determination. I don't see any sense in doing so because as I understand I have to set first this register and calculate the dow. I did not try it that way. I live in Luebeck. Many years ago I traveled through the States. I like the Everglades, the Keys and Manatee Springs ... all american state parks! Ich auch! 
Michael |
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| viscomjim Guru Joined: 08/01/2014 Location: United StatesPosts: 925 |
If you use the for next you have... For I = 0 To 6 Read Days$(I) Next I Data "Sunday" Data "Monday" Data "Tuesday" Data "Wednesday" Data "Thursday" Data "Friday" Data "Saturday" When you read RTCbuff(3) you can use that for I and that will be your day of the week. Once it is set, you can just read that register and you will have your day of the week without having to calculate it. I think the calculation was there only to initially be able to program the DS3231. I agree with you on the other RTCs, once I was able to use the DS3231, I don't like the others either. They drift way too much for me. Luebeck, only 2.5 hours away from my old home. |
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| twofingers Guru Joined: 02/06/2014 Location: GermanyPosts: 1133 |
Hi viscomjim, I'm sure this should work. I was just too lazy to write a Sub to set the DOW-register. Yes. My DS1307/PCF8563-modules drifts about 0,5sec/h. The DS1307 consumed 2,2µA, including die voltage divider. To test the PCF8563 (and Geoffs great improvment RTC GETTIME/SETTIME) I just cutted the DS1307 out and replaced it with a PCF8563 (10 pieces for 1,7 EUR at ebay). PIN 3 = NC. PIN 8 = D1/R6. It takes about 0,5µA (without R4). I did find no way to correct the drift. 
The image above shows a DS1307-module with a replaced PCF8563 (DS1307<->PCF8563). eBay-DS1307 modules - the schematic - are made for lithium accus (LIR2032) but often sold with a CR2032 battery. The DS3221 seems to be the able to tune its frequency by software. But 2ppm is enough for my purposes. Yes. Near the baltic sea. Michael |
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| viscomjim Guru Joined: 08/01/2014 Location: United StatesPosts: 925 |
Hi TF, I just tried both yours and TZ's calculation for Day of Week using the following... For D = 1 TO 7 DATEX$ = STR$(D)+"/8/2014" print "dateX$ = ";DATEX$ a = Int((14-Val(Mid$(DateX$,4,2)))/12) m = Val(Mid$(DateX$,4,2)) + 12*a - 2 y = Val(Mid$(DateX$,7,4)) -a day = Val(Mid$(DateX$,1,2)) DowTZ=(day+y+Int(y/4)-Int(y/400)+Int(31*m/12)) Mod 7 dowTF=(day+y+Int(y/4)-Int(y/100)+Int(y/400)+Int(31*m/12)) Mod 7 print "tz calculation = ";dowTZ print "tf calculation = ";dowTF NEXT D and the results were the same as follows... RUN dateX$ = 1/8/2014 tz calculation = 0 tf calculation = 0 dateX$ = 2/8/2014 tz calculation = 1 tf calculation = 1 dateX$ = 3/8/2014 tz calculation = 2 tf calculation = 2 dateX$ = 4/8/2014 tz calculation = 3 tf calculation = 3 dateX$ = 5/8/2014 tz calculation = 4 tf calculation = 4 dateX$ = 6/8/2014 tz calculation = 5 tf calculation = 5 dateX$ = 7/8/2014 tz calculation = 6 tf calculation = 6 Without racking my brain too much, they both seem to work fine. |
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| twofingers Guru Joined: 02/06/2014 Location: GermanyPosts: 1133 |
Hi viscomjim As I explained yesterday (see above at 13 August 2014 at 4:57pm) it is TZs algorithm: (day+y+Int(y/4)-Int(y/100)+Int(y/400)+Int(31*m/12)) Mod 7 To verify try please: date$="01.01.2000" a saturday (DOW=6). Michael |
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| viscomjim Guru Joined: 08/01/2014 Location: United StatesPosts: 925 |
Ahhhhhhh, thats interesting. Will have to explore a bit more. Thanks TF. |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9063 |
Back on page 1: [Quote=jman]You can do a drop in replacement and it should go fine. [/Quote] He was right, and I can confirm that the DS3232 as a direct replacement for the 1307 works just fine, and it is much, MUCH more accurate over several days then the drifty 1307. The 1307 does have cost advantages over the much more expensive 3232 though, so I guess it depends on what you want. However, I am happy to be able to report that the 3232 works perfectly right out of the box with the Maximite. Smoke makes things work. When the smoke gets out, it stops! |
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