ROM test method

Abstract

Abstract PURPOSE:To avoid a trouble such as a program runaway which occurs when the program is changed, by preparing the program matching information that is loaded to an RAM based on an ROM and a control program stored in the ROM and then comparing the matching information after loading. CONSTITUTION:After a power is supplied, it is checked whether the vertical parity bit for each horizontal bit of an ROM2 is an odd bit or not. A CPU5 executes a loader in the ROM2 to load the information to an RAM4. A revision number REV is read out of an address where the REVs given from the ROM2 are stored and then compared with another REV that is previously stored. Then an ID number is read out of an address where the ID numbers given from the ROM2 are stored and compared with another ID number. When the coincidence is obtained from these comparisons, an ROM test is over. Thus an error occurring when the number is changed can be detected to avoid a program runaway.

Inventors

• 👤 Takatoshi Ishii
• 👤 石井　孝寿
• 👤 Tsutomu Takenaka
• 👤 勉 竹中

Bibliographic Details