Method of internal self-test of microprocessor using microcode
US4641308A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 3, 1984 |
| Grant date | Feb 3, 1987 |
| Priority date | — |
| Expiry date | Jan 3, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L12/433
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A microprocessor device is used in an adapter for a communications loop of the closed ring, one-way, token-passing local area network type. Each station has a host processor with a host CPU, a main memory, and a system bus, and has an adapter including the microprocessor tested according to the invention. The adapter coupled to the main memory by the system bus and includes a local CPU (the microprocessor), a local read/write memory, and a local bus. A transmit-and-receive controller is coupled to the local bus to directly access the local read/write memory; when this station receives a free token, the transmit-and-receive controller copies the message frame to be transmitted from the local read/write memory to the outgoing signal path, converting from parallel to serial. When a message addressed to this station is received, the controller converts it from serial to parallel, and copies the message frame into the local read/write memory via the local bus. Testing of the microprocessor is accomplished by internal self-test of the registers of the device, using the microcode of the control ROM initiated by a test control input.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.