GPO and Keypad Probs

Sheik Yerbuti · Post by **Sheik Yerbuti** » Sat Feb 15, 2003 10:50 am

Howdy I am having the following problems with my new LK204-25PC display
and was hopping some of you boffs could help

1.) All my gpo's work fine except for my 2 cold cathodes, it seems that when i set the gpo on in LCDC it only sometimes comes on (I then have to start and stop my display 3 or more times and then only the lights will come on) Flashing and strobe modes work perfect all the time. this is the same on any of my gpo's and with either of my cold cathodes.(each time i start my display with lcdc the cathodes flash once and then stay of until a few restarts)

2.)My Keypad connector.
I have connected 8 wires to my keypad connector (pins 1-4 and 7 to 10)
so correct me if im wrong but if i short pin 1 and pin 7 I should get a keypress? this only worked the first time i tested it with HyperTerm. after that it seems to only respond when it feels like it ie if i try HT i can SOMETIMES get a letter on the screen and then only one and then there is no response from any combo of keypresses.

I hope someone can help me
Thanks in advance

Sheik

Post by **Henry** » Sun Feb 16, 2003 9:19 pm

1. The Cold Cathode can draw too much current on power up. I have seen the GPO doing what you are describing, and I do not have an easy fix. The "fix" is if you put a small resistor between the MOSFET and the processor, you wouldhave to cut the trace and solder a resistor there.

2. Check your debounce settings on the keypad, test the keypad using a wire as well.

Sheik Yerbuti · Post by **Sheik Yerbuti** » Mon Feb 17, 2003 12:02 am

Hi Henry thanks for the reply
The Cathode problem seems to have sorted itself out, the last 10 or so restarts they came on fine so who knows

at least its working.

Where/what is a debounce setting and how whould i set it

Thanks Again

Sheik

Post by **Henry** » Mon Feb 17, 2003 12:19 am

Look at the LK204-25-PC manual on the main website.