1. An analog to digital conversion apparatus comprising: an input multiplexor circuit having a plurality of analog input terminals for receiving a plurality of analog input signals, said input multiplexor circuit being responsive to a select input; an analog to digital converter circuit adapted to convert the selected analog signal into a digital signal; a conversion starting device adapted to send to said analog to digital converter circuit a conversion start signal on the basis of a selected trigger event of a plurality of trigger events, the conversion starting device being responsive to at least one select input; a sequencer coupled to the select input of the input multiplexor circuit and to at least one select input of the conversion starting device and adapted to control the analog to digital converter circuit to execute one sequence conversion on the basis of one conversion sequence instruction; and a FIFO register block adapted to receive a plurality of conversion sequence instructions and being able to queue each new received conversion sequence instruction if an actual conversion sequence is in progress and is adapted to control the sequencer to execute a new sequence conversion instruction after the actual conversion sequence is completely executed.