rtc and LCD questions

S

SAborn

Senior Member
Also on my 2x16 LCD how do I get it to display numbers or letters on both lines?
Click to expand...
If you are using parallel mode for the LCD, then you need to send an instruction to the display to tell it which line to write the data too, 128 = line one, 192 = line two, look up the instructions foe a 16x2 display as there is many instructions, like curser position, clear display, scroll message, etc, etc.
 
A

ac21

Member
SAborn said:
If you are using parallel mode for the LCD, then you need to send an instruction to the display to tell it which line to write the data too, 128 = line one, 192 = line two, look up the instructions foe a 16x2 display as there is many instructions, like curser position, clear display, scroll message, etc, etc.
Click to expand...
yes i'm using parallel but what i meant to say is write on both lines so the text is bigger.
 
T

the old fart

Senior Member
Good luck using that rtc.

I have a number of these units, even replacing the crystal with a pucka £4 watch crystal, none have kept good time.

I now use the DS3231 RTC, even then I had to tweak the 'crystal ageing' register.
 
neiltechspec

neiltechspec

Senior Member
I think I have to disagree with the comment above. Depends on what you want them for.

I've got 3 of these, using them for none second critical timing events. One of them needed the xtal replacing, the other two didn't.

On all three though, I have removed the rechargeable button cell and replaced with a Maxell brand name lithium battery, obviously removing the charging components.

All within a second a day, which is more than adequate for my needs. I reset the time on a 6 monthly basis.

I am using them in data loggers for solar inverter stats collection, so within several minutes is adequate, just needs to be dark when data is written to SD card.

Neil.
 
T

the old fart

Senior Member
I've used 3 different sources for these rtc, worst one was 45 seconds a day fast. Best one, with £4 crystal, 1 second a day fast.

I tried to use them for clocks and timers.

except for the eeprom address, the DS3231 is a direct replacement and a much better unit to use. IMHO.
 
neiltechspec

neiltechspec

Senior Member
I wouldn't use them for time critical stuff.

But like I said for what I want they are adequate & cheap, £2.85 inc p&p from UK !.

edit: I suppose I should have a play with the DS3231, so just bought one off the bay @ £2.99 inc (supposed to be UK).

Neil
 
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J

john2051

New Member
Hi, most of the problems with the ds1307 accuracy can be tracked down to ignoring the ground plane recommendations given
in the datasheet. Even the crystal loading gets overlooked by some cheap manufacturers. I've used these with properly loaded
crystals, and with a trimmer cap the accuracy can be quite good. If you set the sqw/out pin to 32768kHz, you can adjust the trimmer
for reasonable accuracy.
regards john
 
A

ac21

Member
well i used a 20m2 and made a "backpack" for the lcd, and am able to send serial commands, i set the time and will be monitoring it.

Hey you old fart:D is there a example for 16x2 like this
I tried editing that code to work but failed
 
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