| 摘要 |
PROBLEM TO BE SOLVED: To match the input/output signal levels of a counter memory interface part without damaging reliability on communication by supplying a voltage from one of first and second constant voltage circuits corresponding to the power supply voltage system of a memory to a control circuit provided with the counter memory interface part. SOLUTION: As the memory 20, the one of a 3.3 V power supply voltage system for instance is used and selective power supply connection parts 7 and 8 are connected. In the state, the Vs2 power supply of -3.3 V is supplied to the memory 20 and the control circuit 18 and the input/output signal levels between the memory 20 and the counter memory interface part 19 are turned to the state of being matched by the same Vs2 power supply system, however, the Vs1 power supply of -5 V is supplied to a reception demodulation circuit 14 and a transmission driving circuit 17. Also, in the case of using the one of a -5 power supply voltage system as the memory 20, it is sufficient to attain the state of connecting the selective power supply connection parts 7 and 9 and all circuit parts inside this card are operated by the Vs1 power supply system in that case. |
