| 摘要 |
PURPOSE:To find out the abnormality of option ROM by self-diagnosis at the closing time of a power source when abnormality is generated in the option ROM to display the presence of abnormality, by judging whether the option ROM is connected and performing self-diagnosis only when said ROM is connected. CONSTITUTION:At first, the signal of a signal line 15 is read from an input port to judge whether option ROM13 is connected. When said ROM13 is connected, checking is performed according to the check sum previously provided in the address of the option ROM13 every 64 kb but, at this time, three places of a low address, a middle address and a high address are drawn out to perform checking. When the check result of each address is not normal, a signal is outputted to the output port 16 of CPU16 to allow a display panel 14 to turn ON and OFF according to a predetermined error display method. |
