Control unit esp. for ignition and fuel injection in motor vehicle - has RAM emulation memory allowing data to be manipulated to suit different conditions

A RAM (10) and EEPROM (11) are switched in parallel via a data bus (12). A switching unit (13) allows connection to either aerial interface (16) or a control unit (14) that handles an ignition and/or fuel injection unit on an engine. The control unit (15) for the serial interface has coupled address counter (17). A computer terminal (19) is coupled to the interface. A synchronising control unit (20) controls the switch. The complete unit forms a data manipulation circuit (23) in which data can be entered into the RAM in one emulation cycle and in a second can be loaded into the EEPROM finally as established data. ADVANTAGE - Provides flexibility is changing data for different applications.