Cheaper uC than the atmega169?

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Hey guys

 

I have been building a speedometer and trying various different things just out of boredom mostly. One major issue I am experiencing is space! I am struggling to etch boards because I need to fit so many components on the board and the traces become so small I end up etching 5 boards before i get one that does not have a short or a etched off trace.

 

Currently I have a 2 digit LCD and I am using 2 CD4055BM chips to drive the LCD. in addition to this i am using a separate charge pump circuit to bump 3v coin cell to 5v for the LCD. In addition to this i have an atmega168 to drive the LCD driver chips. All in all Its a lot of components and I am sure there is a integrated solution i am just not too sure of it. Someone suggested a atmega169 to me and by the looks of it it could work. I see the atmega169 has capabilities to drive LCD's of up to 25 segments, I  am just not sure yet if it could bump the voltagefrom 3v to 5v. One issue with this chip is that it's very expensive.

 

Could you guys please suggest a chip i could use to drive up to 2 segments (8 pixels/segment) with minimal components at a relatively cheap price?

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Interesting question, if I pop over to Digikey and search

Microcontroller LCD

I get parts starting from 84c/1k from NXP(Freescale), ST, Microchip, Renesas, Cypress, TI, SiLabs, Epson, Nuvoton, Rohm, Zilog, 

 

Atmel appear on page 18, with a ATXmega64

 

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Hi,

 

maybe it's not the controller but the distributor? Transfer Multisort Electronics sell it in TQFP package for 3.10$ a piece or cheaper if you order more than one. Look out for the non-V version, the Vs are expensive indeed.

 

Cheers

 

P.S.: I recommend having your PCBs made by Elecrow or ITead. There are others of course but those two are the ones I tried myself. You get 10pcs 5cm*5cm boards for about 10$ total plus shipping, which depends on where you live. This can save a lot of time and effort while allowing thinner traces and more vias without additional work.

"Some people die at 25 and aren't buried until 75." -Benjamin Franklin

 

What is life's greatest illusion?"  "Innocence, my brother." -Skyrim

 

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Thanks guys. I found this chip http://za.rs-online.com/web/p/lcd-display-drivers/7575028/ it shows it has an internal charge pump and it can drive 32 segments. Is this the right kind of chip? or is this used for something else?

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calvingloster wrote:

Thanks guys. I found this chip http://za.rs-online.com/web/p/lcd-display-drivers/7575028/ it shows it has an internal charge pump and it can drive 32 segments. Is this the right kind of chip? or is this used for something else?

Sure, that CP2402 is fine to connect to a Small MCU - it allows you more choice on which MCU to use, without being forced to select a LCD capable MCU.

 

Sometimes the LCD can be on a separate panel PCB, and then a Serial LCD driver can make even more sense.

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I'm trying to see if the CP2402 can bump up 3v to 5v but I don't understand the data sheet so well. It shows the maximum voltage is 3.25v

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Run the micro on 3V then. That saves the charge pump to get 5V. Less parts.

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Kartman wrote:

Run the micro on 3V then. That saves the charge pump to get 5V. Less parts.

All good and true only problem is my LCD needs 5v else the contrast is too light.

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Hi,

 

if I understood the datasheet correctly, this chip would do exactly what you need but it can't drive the LCD at 5V. It doesn't go above 3.44V. So it's no useful for you it seems.

 

Cheers

"Some people die at 25 and aren't buried until 75." -Benjamin Franklin

 

What is life's greatest illusion?"  "Innocence, my brother." -Skyrim

 

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Use one of those adafruit 128x32 oleds. Good contrast.

Imagecraft compiler user

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calvingloster wrote:
Could you guys please suggest a chip i could use to drive up to 2 segments (8 pixels/segment) with minimal components at a relatively cheap price?
XMEGA B3.

But, it's for 3V LCD; could evaluate the LCD that's on the XMEGA B1 Xplained to start a search for LCD.

64 pins in 0.8mm pitch QFP or 0.5mm pitch QFN.

Contains a charge pump to generate the LCD bias.

http://www.atmel.com/devices/ATXMEGA128B3.aspx

An alternate way is a mega328 with a port expander for the LCD interface; an example though not a segment LCD : http://www.whizoo.com/ (ControLeo2 Reflow Oven Controller)

 

"Dare to be naïve." - Buckminster Fuller

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bobgardner wrote:
Use one of those adafruit 128x32 oleds. Good contrast.
Indeed but need significant current and are not sunlight-readable.

Segment LCD are commonly lit by the Sun or one's headlamp.

But, from Adafruit, is the Sharp Memory LCD (module, software); very low current and sunlight readable.

Major distributors can supply some to most of the Sharp Memory LCD line; at least one of those is for wrist watches and a mix of 3V or 5V power.

Adafruit Industries, Unique & fun DIY electronics and kits

SHARP Memory Display Breakout - 1.3 96x96 Silver Monochrome ID: 1393 - $39.95

https://www.adafruit.com/products/1393

"Dare to be naïve." - Buckminster Fuller

Last Edited: Tue. May 10, 2016 - 10:04 PM
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bobgardner wrote:

Use one of those adafruit 128x32 oleds. Good contrast.

That's how the OP started on this merry-go-round.  I doubt he wants to get back on it.  Remember, this is (likely) for the cyclometer he has been working on across about a dozen threads. 

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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calvingloster wrote:
All good and true only problem is my LCD needs 5v else the contrast is too light.

Did you check that ?

With Static Drive, I would expect the 3.44v max to be ok ?

 

If you really need 5V or above, then you need to find a matching LCD driver - I see PCF85162 and  BU9797 show up as 5.5V LCD, or you can trawl the Microcontroller LCD search to find one that is both Static capable and 5V capable ?