This is a problem with AD5254 four channels digital potentiometer.
I am writing to RDAC (0:3) registers to set wiper resistance. The first three
times the result is OK. But when writing the fourth time the value is wrong.
The writes are single write type. WP is tied to 3,3V (Vcc). AD0,AD1 are tied to
gnd. Ai is left floating Bi are tied to gnd and resistance WiBi is measured.
I haven't found in datasheet anything that helps explain this way of operation.
If somebody can recognize some similar situation please help me.