Which PIC for LCD and 7 Segment Displays?

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JDR04
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Which PIC for LCD and 7 Segment Displays?

Post by JDR04 »

Hi everyone. I want to teach myself how to use a microchip chip to drive LCD's and 7 Segment displays.

Can somebody suggest a chip that would be suitable for a beginner. Nothing to fancy, perhaps to build a counter or temperature sensor.

Thanks folks, take care and stay safe..........John

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Bachman
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Re: Which PIC for LCD and 7 Segment Displays?

Post by Bachman »

Hello!

First, let me recommend some PIC microcontroller for the future. Programming language like Flowcode, is very easy of use and fast but there is a price for this, the end program (the .hex file) is larger. To handle this, you need microcontroller with larger memory regions (RAM & ROM). If you make friendship with only some type of PIC, your life will be easier.

8 pin: PIC12F1840
14 pin: PIC16F1825
20 pin: PIC18F14K22
28 pin: PIC18F26K22
40 pic: PIC18F46K22

These controllers not the newest types. If you need some special feature, you have to find a differend controller. But for the beginning, I think, these are the best.

LCD needs "lots of legs" and some special C codes because Flowcode does not support it directly. For example, check PIC16F1933 datasheet, section 27. Be careful, not to mix up this type of LCD with the classical characters LCD (most common type is 16 x 2 characters). The 16 x 2 LCD contains LCD driver and Flowcode can handle it, requires six legs.

LED display also needs lots of legs if you're using direct drive. One leg, one segment. Eg. 18F26K22 and three digits. You need 3x7 legs for the segments, three power legs, one leg for 1-Wire (DS18B20 sensor). SUM: 25 legs. If you need only the temerature, it's ok, you need only current drivers.
Other option is to drive the segments with matrix type drive. This needs more CPU time, you have to be careful during programming.

Personally I don't prefer driving the displays directly by the controller. What I like:
Matrix LED drive: MAX7219
Direct drive: PCA9685 (very fine adjustable PWM driver) + ULN2803

Check my clock. Because of the different sizes of the 7seg displays, some fine-tuning required to get equal brightness of the segments. GPS receiver, PIC16F1825, 3 x PCA9685, LDR to automatically adjust the segments brightness.
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JDR04
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Re: Which PIC for LCD and 7 Segment Displays?

Post by JDR04 »

Hello Bachman, thanks for taking the time to help me out. I will go through you post again so that I can understand it better.

Take care, stay safe and have a great Christmas.

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