Choice of a 2x20 LCD Display

[Bertrand BAROTH]

Hello again ...
I wanna buy an alpha display and have the choice between 2 controllers : the ST7066U-0A-B and the S6A0069-22 ; which of them is better (in connection mode 4) together with GC Basic ? Thanks for any answer ...

[Anobium]

Can you share the URL to the specificions?

[Bertrand BAROTH]

ST7066U-0A-B : https://www.crystalfontz.com/controllers/datasheet-viewer.php?id=282

S6A0069-22 : https://orientdisplay.com/wp-content/uploads/2018/08/S6A0069.pdf?_ga=2.261917003.716369086.1754919408-1063401245.1754919408

[Anobium]

GCBASIC-compatible option:

• Winstar WH2002A – HD44780-compatible, 20x2, parallel interface

[Bertrand BAROTH]

So, none of these ?

[Anobium]

Check if they are HD44780-compatible.

[HackInBlack]

WH2002A is a Character LCD 20x2 display which is built in with ST7066 controller IC.

https://www.winstar.com.tw/products/lcd-display/character-lcd-display-module/lcd-20x2.html

[Bertrand BAROTH]

Meanwhile I found and ordered a 2x20 display with a HD44780 compatible controller (and even low power OLed ! ) Now two questions :

1) Since the header in the example is for PIC and I am using AVR's, and I wonder if all connections of the LCD are only inputs, is this header OK :

#Define Ddr_interface DdrB
#Define Inp_interface PinB
#Define Outp_interface PortB

#Define LCD_IO 4
#Define LCD_DB4 Outp_interface.0
#Define LCD_DB5 Outp_interface.1
#Define LCD_DB6 Outp_interface.2
#Define LCD_DB7 Outp_interface.3
#Define LCD_RW Outp_interface.4
#Define LCD_RS Outp_interface.5
#Define LCD_Enable Outp_interface.6

Or does the compiler manage the directions ? Pin7 will be defined and used as an input.

2) If I send successively the two sequences : locate (0,0) and print ("...") and then locate (1,0) and print ("..."), should I add a "wait" instruction between, or does the display manage this (I wonder how, if all lines are only inputs ...) ?

Thanks for Your answers ...

[HackInBlack]

look in:-
"C:\GCstudio\gcbasic\demos\LCD_Solutions\Eight_Wire_LCD_Solutions\LCDCURSOR_8WIRE_TEST_ATMega8_LCD8Bit.gcb"
for a clear description of LCD headers for AVR Mega chips

[Bertrand BAROTH]

Unfortunately I use the "old" GCBasic, not GCStudio. Could You please attach the file ?

[HackInBlack]

sure no problem

[Anobium]

Here are my thoughts based upon the Help.

Do not try to be clever with the Constants. Use the following.

#Define LCD_IO 4
#Define LCD_DB4 PORTB.0
#Define LCD_DB5 PORTB.1
#Define LCD_DB6 PORTB.2
#Define LCD_DB7 PORTB.3
#Define LCD_RW PORTB.4
#Define LCD_RS PORTB.5
#Define LCD_Enable PORTB.6

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If you are not going to read the LCD ( many people do not ) delete #Define LCD_RW PORTB.4 and replace with #DEFINE LCD_NO_RW. This save a pin.

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All pins are managed by the library.

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All performance is managed, start with #DEFINE LCD_SPEED SLOW then try the faster options. The performance is really down the LCD itself.

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There are no need for delays. This is all managed.

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Install the demonstration pack. It has nothing to do with Legacy or Modern IDE. Meanwhile, here are many demo for your config. https://github.com/GreatCowBASIC/Demonstration_Sources/tree/main/LCD_Solutions/Four_Wire_LCD_Solutions

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The LCD library is on of the oldest library and you should be able to use all the functionality in the Help and in the demos.

[Bertrand BAROTH]

Thanks for all Your answers ...