PBP doesn't have a nibble variable type. But like you say, just use a byte with only the low nibble doing things.

Doing 4 bit writes to a single port one after the other, is actually doing 4 full port R-M-W's

If there's no capacitance, it'll be fine.
But if there is. You may have problems.

The method above is only 1 R-M-W at a time.
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