Externally reprogrammable vehicular microcomputer with hardware lock-out of unauthorized memory modifications

US4751633A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Michael Henn · Lehre, DE
• Walter Hersel · Leonberg, DE
• Siegfried Hertzler · Stuttgart, DE
• Rudiger Jautelat · Tamm, DE
• Werner Jundt · Ludwigsburg, DE
• Gunther Kaiser · Stuttgart, DE
• Michael Kirschner · Alpharetta, US
• Dieter Mayer · Ludwigshafen, DE
• Klaus Meyer · Ditzingen, DE
• Manfred Mezger · Markgröningen, DE

Key dates

• Filing date: Mar 11, 1985
• Grant date: Jun 14, 1988
• Expiry date: Mar 11, 2005

Classification

• Technology area (CPC G): Physics
• CPC primary: G05B2219/25178
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

To prevent change of data in a non-volatile programmable, ready-only memory (25) forming, together with a microprocessor (23) a control unit, for example for an automotive vehicle, while permitting programming of the memory from an external programming unit (P, 1), an interface (3, 11, 12) is provided through which a release-enable bus (13) also passes, data being transmitted in accordance with a predetermined characteristic--even or odd parity--, the parity correctness being checked. If the parity is correct, an "enter" signal is provided on the release-enable bus for storing the data; if not, retransmission is attempted for a predetermined number of time, and if it cannot be correctly effected, a malfunction indication output signal is generated.