Microcontroller device having remotely programmable EPROM and method for programming

A method of programming a programmable nonvolatile first memory of a data processing device utilizing a host computer separate from the device, with the device being implemented in a single integrated circuit and having a central processing unit which accesses application code stored in the programmable nonvolatile first memory at a range of the programmable nonvolatile first memory addresses, said method comprising the following steps:

• storing a control program in a nonvolatile second memory of the device separate from the nonvolatile first memory;
• transmitting commands from the host computer to the device, the commands including write address information and write data information for the nonvolatile first memory;
• causing the central processing unit to execute the control program so that, during execution of the control program, the programmable nonvolatile first memory will be programmed at addresses based upon the write address information with data based upon the write data information;
• and
• causing the central processing unit to then access the programmable nonvolatile first memory while preventing the central processing unit from accessing the control program in the nonvolatile second memory,
• whereby the host computer can be used to write any selectable data into the programmable nonvolatile first memory at any address thereof within the range of programmable nonvolatile first memory addresses.

A data processing device implemented in a common integrated circuit which is programmable by way of a separate host computer, said device including:

• a central processing unit;
• a data bus associated with said central processing unit;
• a data input/output port coupled to the data bus and including at least one external connection pin of the device;
• communication port means, separate from said data input/output port, for providing a communication channel between the host computer and said central processing unit, with the communication channel carrying commands originating from the host computer, said commands including write data information and write address information;
• a programmable nonvolatile first memory which is coupled to said data bus capable of storing an application code to be processed by the central processing unit within a range of programmable nonvolatile first memory addresses;
• and
• control means, including a control second memory in which a control program is stored, for causing said central processing unit to execute the control program so that data is written into the programmable nonvolatile first memory during execution of the control program based on the command write data information of one of said commands received by the central processing unit at an address based upon the write address information of one of said commands received by the central processing unit.