16x2 LCD Display and Keypad Shield Reset Button Issue

Has anyone experienced a problem with the reset button (or any other button?) with the DFRobot 16x2 LCD Display and Keypad Shield?

I have two of these units attached to a UNO R3 (two of each). On one of them, when I press the Reset Button, the LCD text becomes garbled and pressing buttons does not correct the issue. When I remove the power and then boot up again, all appears normal until the Reset Button is pushed... again... garbled text.

The board, components and the solder looks very good, no visible defects anywhere. When attached to the UNO R3, none of the soldered items are grounded.

Attached is the code I am working with, compiled and uploaded with Arduino.1.6.12.

Any insights?

2237124SampleCode.zip (5.63 KB)

I've run into a few odd issues with the DFRobot keypad LCD shield. Main problem, is if I try to upload a sketch to any of the following: Duemilinove, UNO R2, or even DFRobot's own MEGA2560 R3 clone, with the keypad plugged in, the board refuses the sketch. But, if I remove the shield, everything works normal. This is the version where they have the LED backlight wired through a transistor, which is constantly switched on by a resistor to +5V (NOT the older versions which used D10 as the On/Off) The Backlight seems to draw too much. You may be experiencing the same, where the backlight is overloading the +5 , to the MCU's supply (+3?) Only thing I haven't tried, was boosting the +5V externally with another supply source. (feeding regulated +5V from a 7805 to the +5V Pin)

I've tried removing the LCD by desoldering the pins, But whatever grade solder they used, even a 45W desoldering iron is brutal, and not effective. (Not wanting to destroy the board or LCD!)

timmfisk:
Has anyone experienced a problem with the reset button (or any other button?) with the DFRobot 16x2 LCD Display and Keypad Shield?

I have two of these units attached to a UNO R3 (two of each). On one of them, when I press the Reset Button, the LCD text becomes garbled and pressing buttons does not correct the issue. When I remove the power and then boot up again, all appears normal until the Reset Button is pushed... again... garbled text.

The board, components and the solder looks very good, no visible defects anywhere. When attached to the UNO R3, none of the soldered items are grounded.

Attached is the code I am working with

No problems here so far. I have four clones of the DFRobot "LCD Keypad Shield" which I ordered within the last four years at different vendors in China.
Two of my LCD Keypad Shields show white characters on blue background
Two other LCD Keypad shields show black characters on yellow-green background.

The LCDs with white chacters need the !backlight always ON" or the visibility will fade away after some time.
The LCDs with black characters can be operated with or without backlight.

All of them working pretty fine when used with a suitable sketch.

WHERE IS THE CODE YOU RE USING?

Which is the code you are working with?

The ZIP file archive contains three Arduuno sketeches:

  • BarChart
  • ButtonTest
    -GuessTheNumber

What are you doing with us?

Do you want us to be mind readers and guess which of the examples in the ZIP archive you are actually talking about?

POST YOUR CODE INLINE IN A FORUMS MESSAGE INCLUDED IN code-tags.

THIS IS NOT A MIND READER FORUM!

SO I TELL YOU ONCE AGAIN: POST YOUR CODE!

Post it within code-tags!

DON'T post ZIP file archives with several sketeches and don't make us guessing which code you are actually referring to!

Hello, timmfisk, have you figured out with your issue? I have the same problem. Reset button causes a serious impact to LCD. I am sure that a reason for this is that you can reboot Arduino even at the moment when some information is transmitted to LCD.

So, I also can replay a normal working messages on LCD unplugging USB and then connecting it again.
Or unplug an LCD pin 2, press 'reset' and after 0.5-1 second connect pin 2 again to VCC, it will work normally.