Start testing with 1.5V, if no segment is ON, then test with 3V, then 5V... Most probably, your LCD is 3V.
BTW, don't lean so much, you'll fall

I like that. However, I hear that brute force is not always a good substitute for finesse, so I am trying to consider doing things the right way instead of just hammering it out

I guess someone stole my 'r'

Next I can work on learning to type.

 

Why not. But what ASMV is
You should read some doc on LCD multiplexing. Microchip and National Semiconductor have some solid & didactical ones. I can never explain better than them and it would spare you a lot of questionning & time.
Cheers.

I will look for the docs on multiplexing. ASMV - astable multi vibrator... sounds dirty but it isn't

Figured I could either use a 555 or a couple transistors and a couple RC circuits and get a nice square wave but it would really be pulsed dc rather than a true AC.

 

Do you have access to a function generator?

If so, you can try sinusoidal, rectangle, square, ac/dc, macaroni and cheese, fish sticks, and all that good stuff.

Sorry, haven't had dinner yet.

 

I do not have access to a function generator. I do have a 30 volt AC wall wart so perhaps a little voltage splitting circuit?

 

Ok, now I see, it is done in an interrupt using the AVR, I will let youknwo how it all works out

 

Update on the saga.. I have found a nice document on operating a 4 digit multiplexed lcd from the AVR. Unfortunately, that one uses 4 commons and so each segment pin operated 1/2 of a digit. Nice, that 8 pins will conveniently control all 4 digits.

In my case I have 3 commons, so it takes 3 segment pins to operate each digit. I have 7 digits meaning I need 21 pins, plus the 3 commons for 24 pins total. I assume that means I am using a whole ATMEGA just to drive the LCD. Seems wrong, but we will see if I have enough ports to work with.

In the sample they setup the segment bitmap in an 8 bit variable (output_var) and essentially set PORTC = output_var in one cycle and PORTC = ^ output_var in the next and so forth. That seems very convenient for a sample. However, I am looking at all of PORTC, PORTB and either part of PORTA or some pins from PORTD not already used for the commons.

My gut feeling is that I would be better off using some PCF8574T (i/o port expander)(since I have them laying around) or possibly SN74HC595N (shift register) since I will have some of them soon. I am just not comfortable with the shift to I2C yet, and I assume I have to do that to use either of them. But I could actually use and ATTINY to drive those and not burn up a whole MEGA just to drive an lcd.

I have stated looking at multiplexing, but the stuff I have found seems to be focused more so around inputs rather than outputs but I will keep digging.

This weekend, SWIMBO will be traveling, so let the geekfest commence. I want to see some real numbers before Monday morning!!