Könnte das Dein Problem sein?
Ich lasse die Werte für jede Stelle als dezimalwert in den Chip

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The address pointer in the MAX6958/MAX6959 autoincrements
after each data byte. If multiple data bytes
are transmitted before a STOP condition is detected,
these bytes are stored in subsequent MAX6958/
MAX6959 internal registers (Figure , unless the
address pointer has reached address 01111111. The
address pointer does not autoincrement once address
01111111 has been reached (Table 3).