sparkfun 3.3 v display issues

[aliyesami]

I got this display from sparkfun:

LCD-09054
Basic 16x2 Character LCD - Amber on Black 3.3V

this was a pin for pin replacement for my 5v HD44780 and indeed it is, it worked perfectly BUT it works only on 5v and not 3.3v . this is supposed to be a 3.3v display so what I have to do to make it work on 3.3v ?

I am using LM39401 as 3.3v regulator , is this an appropriate regulator ? my 5v supply is rated at 700mA regulated and 800mA max.


thanks

 

[wp100]

Hi,

When the lcd is running at 3v3, what voltage is being supplied to the driving micro 5v or 3v3 ?

Cannot see anything wrong with the lm3940, but to prove the point take your 5v and run it to the lcd though a series of diodes eg 1n4001/8, to drop the voltage.

 

[bigdogguru]

Are you sure Sparkfun shipped the correct display?

Typically, the displays list the correct operating voltage on the back of the device.

A similar display from Sparkfun, ADM1602K-NSA-FBS/3.3v, it would not be the first time the wrong part was shipped.

Or it could be mislabeled.

P.S.

After examining the product page on Sparkfun, this problem appears to be common issue with the display, review the comments:

Basic 16x2 Character LCD - Amber on Black 3.3V

I've utilized several displays from XIAMEN AMOTEC DISPLAY CO.,LTD, in the ADM1602 series and have not encounter this issue.

Perhaps this is a "bad" batch or mislabeled as previously mentioned.


BigDog

 

[aliyesami]

Hi,
When the lcd is running at 3v3, what voltage is being supplied to the driving micro 5v or 3v3 ?

MCU is also on 3.3v , I switch the whole board supply voltage to 3.3v. you think that the MCU is not working at 3.3v ? its atmega1284p which is suppose to work at 3.3v.

- - - Updated - - -

Are you sure Sparkfun shipped the correct display?

Typically, the displays list the correct operating voltage on the back of the device.

A similar display from Sparkfun, ADM1602K-NSA-FBS/3.3v, it would not be the first time the wrong part was shipped.

Or it could be mislabeled.

P.S.

After examining the product page on Sparkfun, this problem appears to be common issue with the display, review the comments:

Basic 16x2 Character LCD - Amber on Black 3.3V

I've utilized several displays from XIAMEN AMOTEC DISPLAY CO.,LTD, in the ADM1602 series and have not encounter this issue.

Perhaps this is a "bad" batch or mislabeled as previously mentioned.


BigDog

never mind ..my fault I did not replace the DS1307 which was not working on 3.3v and hanging the code . After i bypassed the RTC code display worked fine on 3.3v.
I will be replacing the DS1307 with 3.3v DS1337 today and reporting.