Method for flexibly developing a data processing system comprising rewriting instructions in non-volatile memory elements after function check indicates failure of required functions

A method of developing a data processing system comprising a semiconductor integrated circuit device on a single chip which includes:

• a central processing unit;
• an interface circuit;
• an internal bus coupled to the central processing unit and to the interface circuit;
• and
• a sub-processor coupled to the internal bus and to the interface circuit and including:
• non-volatile memory elements in which instructions are to be stored;
• a control circuit which generates control signals in accordance with the instructions stored in the non-volatile memory element, and
• an arithmetic logic unit which is controlled by the generated control signals, one of the generated control signals being used for controlling the interface circuit,
• wherein the semiconductor integrated circuit device has:
• a first operation mode which enables the non-volatile memory elements to write data, and
• a second operation mode which enables the central processing unit and the sub-processor to perform data processing for the data processing system, and disables the central processing unit to access the non-volatile memory elements,
• the method comprising the steps of:
• (a) in the first operation mode, writing data to the non-volatile memory elements to store instructions;
• (b) in the second operation mode, operating the semiconductor integrated circuit device serving as the data processing system;
• (c) checking whether or not a function of the data processing system which is realized by the semiconductor integrated circuit device operating in the second operation mode satisfies a required function;
• (d) completing development of the data processing system if the function of the data processing system satisfies the required function;
• (e) in the first operation mode, changing the data stored in the non-volatile memory elements so as to satisfy the required function if the function of the data processing system does not satisfy the required function;
• and
• (f) after the step (e), repeating the step (b) to the step (e).

A method of developing a data processing system to be comprised of semiconductor integrated circuit devices each of which is on a single chip and includes:

• a central processing unit;
• an interface circuit;
• an internal bus coupled to the central processing unit and to the interface circuit;
• and
• a sub-processor coupled to the internal bus and to the interface circuit and including:
• non-volatile memory elements in which instructions are to be stored;
• a control circuit which generates control signals in accordance with the instructions stored in the non-volatile memory elements;
• and
• an arithmetic logic unit which is controlled by the generated control signals, one of the generated control signals being used for controlling the interface circuit,
• wherein each of the semiconductor integrated circuit devices has:
• a first operation mode which enables the non-volatile memory element to write data, and
• a second operation mode which enables the central processing unit and the sub-processor to perform data processing for the data processing system, and disables the central processing unit to access the non-volatile memory element,
• the method comprising the steps of:
• (a) preparing the a first one of the semiconductor integrated circuit device! devices for writing data therein;
• (b) in the first operation mode, writing data to the non-volatile memory elements of the first semiconductor integrated circuit device to store instructions;
• (c) in the second operation mode, operating the first semiconductor integrated circuit device serving as the data processing system;
• (d) checking whether or not a function of the data processing system which is realized by the first semiconductor integrated circuit device operating in the second operation mode satisfies a required function;
• (e) completing development of the data processing system if the function of the data processing system including the first semiconductor integrated circuit device satisfies the required function;
• (f) preparing a second one of the semiconductor integrated circuit devices if the function of the data processing system including the first semiconductor integrated circuit device does not satisfy the required function;
• (g) in the first operation mode, writing data to the non-volatile memory elements of the second semiconductor integrated circuit device to store new instructions;
• (h) replacing the first semiconductor integrated circuit device with the second semiconductor integrated circuit device in the data processing system, and operating the second semiconductor integrated circuit device in the second operation mode serving as the data processing system;
• (i) checking whether or not the function of the data processing system which is realized by the second semiconductor integrated circuit device operating in the second operation mode satisfies the required function;
• (j) completing development of the data processing system if the function of the data processing system including the second semiconductor integrated circuit device satisfies the required function;
• and
• (k) repeating the steps (f) to (j) after replacing the second semiconductor integrated circuit device with another semiconductor integrated circuit device if the function of the data processing system including the second semiconductor integrated circuit device does not satisfy the required function.