A mask programmable register (40) determines a default configuration of a data processor during a reset operation. The default configuration is driven to a plurality of external integrated circuit pins (48) of the data processor with weak drivers (528, 534, 540, 546). Then, on an individual pin basis, an external user (11) may choose to allow each integrated circuit pin to remain in a default state or be drive with an external configuration value. When the external user chooses to allow the integrated circuit pin to remain in the default state, an internal default configuration data value provided by the internal mask programmable register is output by the integrated circuit pin. Conversely, when the external user chooses to override the default state, the user may drive the external configuration value to the integrated circuit pin using an external data source.