Real time clock ICs

[Eng4444]

i did the same connections shown in the shematic , downloaded the same program (that is displayed here) inside PIC16F628A, gave 5VDc and checked the connections again. But i didn't see anything on LCD.......

I even added a variable resistor (10 K) for the contrast of LCD and fixed the light in the middle position.

SO now, you will keep on saying that i have to read datasheets??

or you will try to help me in an effective way?

i finished my MEMS laboratory and sent it to canado to be manifactured :-D

Friday i will present it in front of jury and MONDAY..... i'll graduate :-) and since then, i'll pass a whooooooole month in the Carribean!

But right now, since i am used to pressure of work, i'll continue and work on this real time clock. But not now.... during the last month i was sleeping only 4 hours daily and then, working 20 hours on this project non-stop , with just 30 minutes of break for each day.... imagine this situation!!?

so i will just sleep......

Please guys, take it into consideration and check that schematic and program... tomorrow i'll be well awake so i'll concentrate on your replies and try to accomplish what you told me to do..

But please, please , please........ stop talking about datasheets...

By the way:

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They advise people to wear noise-producing devices such as little bells on their clothing to alert but not startle the bear unexpectedly. They also advise carrying pepper spray in case of an encounter with a bear. It is also a good idea to watch for fresh signs of bear activity and know the difference between black bear and grizzly bear droppings. Black bear droppings are smaller and contain berries and possibly squirrel fur. Grizzly bear droppings have little bells in them and smell like pepper spray." :-)

[BobK]

Hi Eng4444,

I wasn't trying to make you nervous by asking for drawings and code work. It just makes it easier to figure out what is going on. At first glance of the schematic I see the following:

1) I think your LCD data lines are wrong. You should tie lines DB0 thru DB3 to ground then starting with DB4 tied to RA.0, DB5 to RA.1, DB.6 to RA.2 and DB7 to RA.3. The Read/Write pin on the LCD needs to go to ground. I tried to get the Datasheet (don't you just love it?) from Winstar but you have to signup with them to get these and I'm waiting to hear back from them so I can verify these connections when using a 4 bit bus. The couple of types of LCDs and VFDs I use start with DB4 when using 4 line bus connections.

2) Pin 3 on the DS1307 needs to go either to a backup battery or tied to ground if you're not using the battery.

3) You should change the pull up resistors on the SCL and SDA lines from 10K to 4.7K.

4) I realize you had a hard time getting this drawn out but I don't see any capacitors. You need a .1uF on the power supply lines of EACH device as close to the device as possible. You should also have a .1uF and a 10uF on each side of the voltage regulator if that's how you are powering this project.

You did mention that you have a potentiometer connected to the contrast pin of the LCD. I didn't see that on the drawing.

Start with the above and try the program above. This may just take care of your problem. I have not sat down with the code. I trust that you have checked and rechecked that. Keep in mind that a single character wrong somewhere can keep it from working correctly. Someone recently had LCBOUT instead of LCDOUT. Big difference!

Good luck!

BobK

[Eng4444]

Hello again :-)

i just wanted to check befor sleeping if someone has answered. and Here i found yours BobK.

thank you for the notes. I'll take them into consideration tomorrow.

Here i attached the datasheet for you. So don't wait for winstar... sometimes they take lot of time.

i hope i provided you with everything.

By the way,

the matter of variable resistor wasn't included because i just forgot to put it. But i assure you that i connected it in a good way and worked fine.

So in case you wanna include or add something, i'll be thankful for the time you gave to me.

Good night now... i'm soooooooooooooooooooo tired :-(

[SteveB]

BobK,
The "datasheet" Eng4444 posted was a bit sparse, but did reference the KS0066 or equivalant controler.

Hope this helps, and it looks like you are correct about the data lines to the LCD, they should be D4-D7 (not D0-D3) in 4 bit mode.

Steve B

[BobK]

Hi Steve,

Yes I saw that information. I was worried since I said that. The displays that Melanie uses must use D0 thru D3. I really didn't want to cross her. Her stuff is really pretty good. I know now I'll feel the pain of her whip! I checked some of the things I did with 4 bit LCD's and they all used D4 thru D7 which is why I said that. I even looked in the PBP manual and that example is also D4 to D7. Later I looked at her 1307 Clock program and said OH NO! But considering everything that ENG4444 has been thru it can't hurt to try it. I do hope it works for him.

Thanks for the datasheet help, Steve. I saved it in my reference files.

BobK

[Jumper]

Hi,

I would like to add a 4k7 resistor between DS1307 (pin7) and 5V as a pullup resistor and as said many times before GND the backup battery pin.

[SteveB]

I haven't gone through the code completely, but taking another quick look at the schematic I noticed there aren't any pull-ups used for the buttons. I did see a TRISB=%11111111 in there, as well as checking one of the buttons low as a condtion in an IF...THEN statement used to enter the SetupEntryLoop (I am assuming the logic is the same on all three). So they are floating, and should be pulled-up. You could just use those 10K pull-ups you removed from the SCL/SDA lines (which should now have 4.7K) and add them to the pins for each of the buttons. Just need one additional for the third button.

Steve

[Melanie]

Gawd, that's a four-year-old program and you expect me to remember what LCD's I was using at the time? I do recall that you could use either the upper or lower 4-bits. On checking the current DATASHEET (Datasheets always seem to come into the conversation on this thread) I find that Tri-T (our currect supplier) only supports the UPPER four bits. So this is obviously non-standard. I'd connect as per the PBP manual, but using the Port pins as specified in the DEFINES within the program. I've tried the original MN1307 this morning (I've not checked the posted version) connected that way and it works.

Buttons are on PortB and use the PICs internal weak pull-up's.

[Eng4444]

The best thing is to have a huge project done ahead of time... everybody there is still working.

I checked all the comments i have. Thank you for your cooperation :-)

how would i know that they should have been D4 throught D7.... i do not work with electronics and i was doing exactly as it was said.

i will try all what was said in 2 hours and then give feedback.

i wish a nice day for everybody!

[Pic_User]

There is project building. Planning and physically building a project. Writing the code and testing. When it does something unexpected (that would include not working). There is “troubleshooting”.

Troubleshooting is an art. There are efficient ways and there are inefficient ways to accomplish the same end. The problem seems to be that some people just want the answer, not the procedure. They seem to think that someone can see their circuit, and mystically, clairvoyantly, pass their long-distant hand over the program or circuit and KNOW what their mistake is.

Real problems arise when the person ASKING for HELP thinks the helper is just asking silly questions and asking them to do silly things. All that the person ASKING for help wants is an ANSWER. So they end up DEMANDING that the foolish, silly, questions STOP, and GIVE ME THE ANSWER that I need.

So we are “stuck” with the “basic” truthful ANSWER , “I Don’t Know”.

See also

i did the same connections shown in the shematic , downloaded the same program (that is displayed here) inside PIC16F628A, gave 5VDc and checked the connections again. But i didn't see anything on LCD.......
...SO now, you will keep on saying that i have to read datasheets??

or you will try to help me in an effective way?

Friday i will present it in front of jury and MONDAY..... i'll graduate :-) and since then, i'll pass a whooooooole month in the Carribean!

...so i will just sleep......

Please guys, take it into consideration and check that schematic and program... tomorrow i'll be well awake so i'll concentrate on your replies and try to accomplish what you told me to do..

But please, please , please........ stop talking about datasheets...

-Adam- (this was mis-posted (by me) should have gone in answer to: http://www.picbasic.co.uk/forum/show...2&postcount=25