On Sat, 30 Nov 2019 18:56:41 +0100, "R.Wieser" 
declaimed the following:


>
>The "I2C backpack" is actually just a dumb 8-bit I2C expander plus a
>backlight-feeding transistor and a potmeter for the contrast.  In short,
>everything you normally feed to the 4-bit interface of the LCD now has to go
>over I2C - hence the previously mentioned checking of the LCD's busy line.
>
>https://artofcircuits.com/product/i2c-io-expansion-interface-board-for-16x2-20
x2-character-lcd-modules-black
>
>By the way: There seem to be two major variants: One using the lower 4 bits
>of the expander for data, and the other (ofcourse) uses the higher bits.
>

 Odd -- I thought 4-bit mode on those displays always used the same four
bits... 8-bit mode, obviously, uses all of them at once.

Complete units
https://www.amazon.com/KNACRO-Backlight-Arduino-MEGA2560-letters/dp/B01ID8O574/
ref=asc_df_B01ID8O574/?tag=hyprod-20&linkCode=df0&hvadid=216499414469&hvpos=1o3
&hvnetw=g&hvrand=14029346745609033987&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&
hvlocint=&
hvlocphy=9017451&hvtargid=pla-350579062681&psc=1

(though the adapter is cheap (once I found a price in $... if you need a
lot of them
https://www.amazon.com/WINGONEER-Interface-Arduino-LCD1602-Display/dp/B06XHGYYW
B/ref=asc_df_B06XHGYYWB/?tag=hyprod-20&linkCode=df0&hvadid=309705947946&hvpos=1
o3&hvnetw=g&hvrand=13894525518166698913&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl
=&hvlocint=&
hvlocphy=9017451&hvtargid=pla-351240310537&psc=1
)
And https://www.newhavendisplay.com/serial-displays-c-253.html have all
three interfaces: UART, I2C, and SPI



--
 Wulfraed                 Dennis Lee Bieber         AF6VN
 wlfraed@ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/

--- SoupGate-Win32 v1.05