Real Time Clock & Eeprom

[sayzer]

Also, for smart_storm's problem, described above, an example can be as below.

Example: Starting from today,16.02.2006, prayer time table for the next 30 days for location: Los Angeles/USA is as below (actual times). Let say these times and dates are in an eeprom.

(six times instead of five times are given)

Date-----Time1,Time2,Time3,Time4,Time5,Time6
-------------------------------------------------
16.02.2006 5 08 6 32 12 14 15 17 17 44 18 58
17.02.2006 5 07 6 31 12 14 15 17 17 45 18 59
18.02.2006 5 06 6 30 12 14 15 18 17 46 19 00
19.02.2006 5 05 6 29 12 14 15 19 17 46 19 00
20.02.2006 5 04 6 28 12 14 15 19 17 47 19 01
21.02.2006 5 03 6 27 12 14 15 20 17 48 19 02
22.02.2006 5 02 6 26 12 14 15 20 17 49 19 03
23.02.2006 5 01 6 25 12 13 15 21 17 50 19 04
24.02.2006 5 00 6 23 12 13 15 22 17 51 19 04
25.02.2006 4 59 6 22 12 13 15 22 17 52 19 05
26.02.2006 4 58 6 21 12 13 15 23 17 53 19 06
27.02.2006 4 57 6 20 12 13 15 23 17 54 19 07
28.02.2006 4 55 6 19 12 13 15 24 17 54 19 08
01.03.2006 4 54 6 17 12 12 15 24 17 55 19 09
02.03.2006 4 53 6 16 12 12 15 25 17 56 19 09
03.03.2006 4 52 6 15 12 12 15 25 17 57 19 10
04.03.2006 4 50 6 14 12 12 15 26 17 58 19 11
05.03.2006 4 49 6 12 12 12 15 26 17 59 19 12
06.03.2006 4 48 6 11 12 11 15 27 17 59 19 13
07.03.2006 4 47 6 10 12 11 15 27 18 00 19 13
08.03.2006 4 45 6 09 12 11 15 27 18 01 19 14
09.03.2006 4 44 6 07 12 11 15 28 18 02 19 15
10.03.2006 4 43 6 06 12 10 15 28 18 03 19 16
11.03.2006 4 41 6 05 12 10 15 29 18 04 19 17
12.03.2006 4 40 6 03 12 10 15 29 18 04 19 18
13.03.2006 4 39 6 02 12 10 15 29 18 05 19 18
14.03.2006 4 37 6 01 12 09 15 30 18 06 19 19
15.03.2006 4 36 5 59 12 09 15 30 18 07 19 20
16.03.2006 4 35 5 58 12 09 15 30 18 08 19 21
17.03.2006 4 33 5 57 12 09 15 31 18 08 19 22

If you check the table carefully, minutes sometime shift for 2 and 3 minutes; not for one minute everyday; or they do not change for two-three days. Lets not think about this part much, unlike the previous post, as they will be prepared to be read.

Given the table, smart_storm can write a clock code and match the hour and minute with the lookup table from eeprom.

For instance, on date 16.02.2006, Time1=5:08 (actualy 05:08 morning time) so that we can store this in time1 and time1x variables as 05 and 08 respectively.
Time1 holds the hour and time1x holds the minute from eeprom lookup table.
If we also use an RTC chip such as DS1302 for instance, and hold the hour and minute in variables DShour and DSminute then we can come up with a sample concept as below.

DShour var byte 'variable: hour from DS1302
DSminute var byte 'variable: minute from DS1302
time1 var byte ' variable: one of six times in a day to store hour from eeprom lookup table.
time1x var byte 'variable: the sister variable of time1 variable to store the minute from eeprom lookup table.
time2 var byte 'other time etc..
time2x var byte '...etc
.....etc.


loop:
gosub read_ds1302 'codes for reading DS1302...
gosub read_eeprom 'codes for reading eeprom lookup table....
gosub do_convertion 'HEX and DEC convertions are done...

If DShour=time1 AND DSminute=time1x then GOSUB buzzer 'to match the time from DS1302 with the time from eeprom, and ifthey match buzz the buzzer.

goto loop



Hope this post and the previous one can help people write a code for prayer times.

[smart_storm]

MR. sayzer

i don't know how i can thank u for great explanation
both in first and second posts

so i said using equations solve all the problems
but it's very difficult not only in PIC but also using PC

so let's stay at the table solution


for now i hope MELANIE understand the problem

as for MR.sayzer when i said 1 min this is because this ensure

that two times will identical at some time

because the change is in minutes

so i hope that some one can help

excuse me but if there is no problem please don't use the RTC DS1302

or any other RTC because in our country we can't find those real time clocks

so i Prefer the programming solution for the clock

another thing you are talking with PICBASIC beginer

this is as for me

i hope mr.sayzer still with us to help

thanks for this special forum

[sayzer]

smart_storm,

Pls provide more details.

How/from where do you want to get the time? If you do not want to use RTC, will you receive the time from a PC or from somewhere else?

Since the minutes are very important for prayer times, if you use classic programming to make a clock generator, it will not be as precise as an RTC, and the timer will either run faster or slower. Eventually you will end up with at least 1-hour faster running timer in one day.

I understand your difficulty of finding RTC chips, but I suggest that you try your best to find an RTC chip somehow. That would be the best solution for a precise time matching.

[paul borgmeier]

smart_storm,

I posted some amazingly short and simple code in the “Examples Section” that will keep accurate time without the use of an RTC (within 2 seconds per day – same as with RTC). The code could easily be modified to keep track of days and you could easily add your lookup table.

See

http://www.picbasic.co.uk/forum/showthread.php?t=2129


Good Luck

Paul Borgmeier
Salt Lake City, Utah
USA

[smart_storm]

thank u MR.Paul Borgmeier for your help
i'll see your post

as for MR.sayzer can Paul Borgmeier program help me or not

if it's neccesary use RTC i will try but i don't sure i can

any way can we modified the code to do what we need

also if there is no RTC i don't care if we lose 2sec/day "this is only for me as starting point"

right now i don't see the code

i hope MR.sayzer see it and said to me your opinion

again thanks for all to care of my ques

sorry for my bad english