| 摘要 |
PURPOSE:To detect address information easily by a simple circuit by writing address information display data in a spare chip. CONSTITUTION:Defective loop control circuit 21', when the supply of address information to data lines 27 is indicated via line 30, supplies address information to data chips 0-7 of 10-bit data lines 25 to bubble generating, erasing and dividing circuit 4, and ''1'' as address information display data to spare chips 8 and 9. Address information detecting circuit 29 is supplied with bits 8 and 9 of data lines 25 and defective loop information 26 and in read operation, detecting circuit 29, when detecting bits 8 and 9 of data lines 25 being both at ''1'' while detective loop information 26 shows that the loop is not defective, sends bits 0-7 of data lines 25 to lines 28 as address information by opening ANG gate 24. Consequently, the address information can easily be detected by the simple circuit. |
