On simply normal numbers with digit dependencies

Given an integer $b\geqslant 2$ and a set $P$ of prime numbers, the set $T_P$ of Toeplitz numbers comprises all elements of $[0,b[$ whose digits $(a_n)_{n\geqslant 1}$ in the base-$b$ expansion satisfy $a_n=a_{pn}$ for all $p\in P$ and $n\geqslant 1$. Using a completely additive arithmetical function, we construct a number in~$T_P$ that is simply Borel normal if, and only if, $\sum_{p\not \in P} 1/p=\infty$. We then provide an effective bound for the discrepancy.