Dennis,

> Odd -- I thought 4-bit mode on those displays always used the same
> four bits

They do, they do.

Its about which outputs of the I2C expander are connected to it.    With
some you need to send the LCD 4-bit data in the upper nibble and the LCD
control signals in the lower to the expander, and others the other way
around.

> though the adapter is cheap (once I found a price in $... if you need
> a lot of them

I'm an hobbyist myself (don't need quantities) and got a single I2C backpack
for 2 Euros.  Not a bad price.

Regards,
Rudy Wieser

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