| 摘要 |
PURPOSE:To prevent the increase of the number of terminals by by-passing switching circuits to connect the address bus and the data bus of a data buffer circuit to the address bus and the data bus of connection terminals after requesting check. CONSTITUTION:When check is requested, switching circuits 53 and 54 are by- passed to connect an address bus 50 and a data bus 51 of a data buffer circuit 45 to the address bus 50 and the data bus 51 of connection terminals 47-49. Consequently, when switching circuits 53 and 54 are so set that the address bus 50 and the data bus 51 of a character data taking-in circuit 44 are connected to the address bus 50 and the data bus 51 of the data buffer circuit 43, taking-in of the character data taking-in circuit 44 is checked through connection terminals 44-49 to prevent the increase of the number of terminals. Further, character data taken into the character taking-in circuit 44 is written in the data buffer circuit 45. |
