| 摘要 |
PURPOSE:To provide the electronic musical instrument to which a foot pedal of any type such as a switch type which is inverted in ON/OFF state when stepped in and a variable resistor type which is inverted in resistance value can be connected. CONSTITUTION:The contact pin J1 of a jack 7 is pulled up by a resistance R1 to a source voltage. Further, when the plug is not inserted, a neutral contact pin J3 which is pressed against the contact pin J1 is grounded by the resistance R1. An A/D converter 8 converts the voltage at the contact pin J1 of the jack 7 into a digital signal and supplies it to a CPU 1. When the plug is not inserted, the A/D converter 8 is supplied with 2.5V which is an intermediate value of the source voltage. When the plug is inserted, a contact CN is separated and when a make type foot pedal which turns ON when stepped in is connected, the A/D converter 8 is supplied with a voltage of >=2.5V, but when a break type foot pedal which turns OFF when stepped in is connected, a voltage of <2.5V is supplied. The CPU 1 judges which foot pedal is connected from the digital value outputted by the A/D converter 8. |
