Microcomputer with internal ram security during external program mode
Номер патента: CA1310136C
Опубликовано: 10-11-1992
Автор(ы): Mark K. Eyer, Paul Moroney
Принадлежит: General Instrument Corp
Опубликовано: 10-11-1992
Автор(ы): Mark K. Eyer, Paul Moroney
Принадлежит: General Instrument Corp
Реферат: ABSTRACT The present invention provides a microcomputer which is operable in either an internal program mode, wherein the microcomputer functions in accordance with an internally stored program, or in an external program mode, wherein the microcomputer functions in accordance with a program stored in a memory external to the microcomputer, without compromising the security of data stored in a designated internal RAM. The microcomputer of the present invention includes an internal program memory for internally storing programs; a bus for connection to an external memory for carrying programs from the external memory; a nonsecure RAM for storing nonsecure data; a secure RAM for storing secure data; a central processing unit for processing the stored data and/or externally provided data either in accordance with the internally stored programs or in accordance with programs stored in the external memory; and a controller for controlling inter-connections between the internal program memory, the bus, the RAMs and the central processing unit in accordance with the mode of operation of the microcomputer; wherein during the external program mode, the controller inhibits access to the secure RAM. Code for accessing the secure data stored in the secure RAM is contained in a program stored in the internal program memory.
Microcomputer with internal ram security during external program mode operation
Номер патента: IL87716A0. Автор: . Владелец: Gen Instrument Corp. Дата публикации: 1989-02-28.