EEVblog #248 - LCD Enabled Microcontroller Selection

Look over Dave's shoulder as he tries to select a 7 segment LCD and suitable driving microcontroller.

[FTBoogie]

This is hands down, the most exciting video on the internet.
I liked the part where he was on Digikey looking at datasheets.

[DesignMitch]

Just spent 3 hours looking for an LED driver with fault monitoring... Not more parametric searching! Keep up the good work regardless Dave.

[EEVblog]

I like using Digikey as a convenient reference point for designing due to their massive selection and mostly usable parametric search. Doesn't mean I will buy from them though.

[EEVblog]

@Hobgoblin612 I was going to double check that. And so it seems that might be the case. The chip might still be usable.

[NivagSwerdna]

Nice topic. I have a similar project and went through exactly the same process and ended up back at a PIC.

[HSPalm]

I didn't know microcontrollers even had numeric LCD/LED display peripherals. I've always just bit-banged them at it works perfectly. If you need less pins to drive them, you can use an alphanumeric driver chip (MAXIM has a few with SPI and I2C) or simply a multiplexer or a binary counter chip.

[ssjgohan]

Funny thing is, I have never designed for more than 100 units production quantity, and in that case the hours you have to put in to actually get the cheapest device are ways more expensive than just taking the top-of-the-line part that you've already used in other projects. Even for 1000 units quantity the real nitty gritty selection doesn't quite always pay off.

[PeterCCamilleri]

It is highly likely that you do not need to used the LCD Voltage pins. The bias voltages can be generated internally. This frees up 3 pis

[JonathanWinterflood]

@skierplaterandy In reflective mode (no backlight), the power consumption is far far lower with an LCD. Also, viewing in bright daylight is fine with a reflective LCD but would require a very powerful LED display.

[KonstantinosKalleris]

Are you in my mind? Just now I was looking for display drivers etc and received an e-mail notification about this video! Thank you, it's very interesting! Do you know if there is an ic display like that but with multiplexing? Thank you again for your nice videos!

[EEVblog]

@skierplaterandy Much lower power consumption for LCD.

[Gobhoblin]

You may not need all the VLDC pins on the pic whitch would free up 1-3 more adc's. Have a look at page 335 of the full datasheet.

[CampKohler]

The LCD datasheet has a no lead symbol. What do they plate the pins with instead of solder?

[medabrundibar]

@EEVblog And better readability on strong external light level, e.g. direct sunlight

[CampKohler]

@FTBoogie If you don't show up for a few days, we know where to find you: sitting in front of your PC clicking the replay button over and over and over.

[Membrane]

What about using a shift register to drive the LCD?

[CampKohler]

@c3br4x Ah, Grasshopper, when you can carry the solder pot full of molten solder from one bench to the other with your bare wrists, you will be ready to go out into the world. But first you must be able to snatch a 1N34 from Dave's hand before he can make a fist.

[Ballanux]

@Xenplex If you are going to buy a lot of things you may consider mouser.com which has free shipping for orders over 75€ and it has as many products as farnell

[DMStern]

Are there any distributors with a parametric search for microcontrollers that's actually useful? Not that the manufacturers are much better. TI and Microchip are the only ones I can think of offhand that do it right (filter by features), but eg. ST just list all combinations as separate entries and expect you to sort it out yourself. Terrible!

(Looking closer, Microchip's product selector looks awfully familiar to TI's old one. Must have gotten it from the same developers!)