Microcontroller with programmable embedded flash memory

Abstract

An architecture for microcontroller with embedded flash memory is provided. The microcontroller allows the reprogramming of data into the embedded flash memory of the microcontroller to be performed on-board without having to dismount the entire IC package of the microcontroller from the circuit board and then use a dedicated writer to perform the write operation. The reprogramming operation can be initiated either by an external reprogramming-enable signal or an internal reprogramming-enable signal. When either of these two signals is generated, it causes an OR gate to output a high-voltage logic signal to a multiplexer to thereby cause the multiplexer to select a ROM unit for connection to the microprocessor unit. This allows the microprocessor unit to execute a reprogramming control routine stored in the ROM unit. The flash memory unit further stores a reprogramming detection/initialization routine which checks whether a flash reprogramming request signal is issued from the main-unit interface. With this microcontroller architecture, the reprogramming of data into the embedded flash memory can be performed on-board without having to laboriously dismount the microcontroller from the circuit board. The reprogramming operation is therefore quite easy and quick to perform, thus more cost-effective than the prior art.