資料24 SR フリップフロップ回路
- 図3の回路を、描いてみます。
- SimsirJSでは、配線を自由に描くことができないので、図3そのままのきれいな破線図にはなっていません。
- NAND ゲート2つと、入力(B1, B2)、 出力 (Q, ￢Q)にあたる部分を、見てください。
- B1, B2は、In B1, In B2の前のトグルスイッチで値(0 ,1) の設定を変えます。
- Qは、Out QにつながったLED Qが赤くなるとき1、黒は0を表しています。
- Q を、この回路がとっている「値」と考えてみてください。 （NAND へ戻っていく Out Qの状態を LEDで計測しています）
- つまり、この回路は、ある時点で0か1かを表しつづけている（記憶している）とみなすことができます。
- 記憶する値を変えるには、スイッチにあたるB1とB2の値を変えます。
| B1 |
B2 |
Q |
￢Q |
注釈 |
| 1 |
1 |
Q |
￢Q |
Q値を保持 （前の値のまま変化しない） |
| 1 |
0 |
0 |
1 |
Qを0にリセット |
| 0 |
1 |
1 |
0 |
Ｑを 1にセット |
| 1 |
1 |
不定 |
不定 |
禁止（使用しない）（両方とも1は、論理的に矛盾） |
{
"width":800,
"height":400,
"showToolbox":true,
"toolbox":[
{"type":"In"},
{"type":"Out"},
{"type":"Joint"},
{"type":"DC"},
{"type":"LED"},
{"type":"PushOff"},
{"type":"PushOn"},
{"type":"Toggle"},
{"type":"BUF"},
{"type":"NOT"},
{"type":"AND"},
{"type":"NAND"},
{"type":"OR"},
{"type":"NOR"},
{"type":"XOR"},
{"type":"XNOR"},
{"type":"OSC"},
{"type":"7seg"},
{"type":"16seg"},
{"type":"4bit7seg"},
{"type":"RotaryEncoder"},
{"type":"BusIn"},
{"type":"BusOut"},
{"type":"RS-FF"},
{"type":"JK-FF"},
{"type":"T-FF"},
{"type":"D-FF"},
{"type":"8bitCounter"},
{"type":"HalfAdder"},
{"type":"FullAdder"},
{"type":"4bitAdder"},
{"type":"2to4BinaryDecoder"},
{"type":"3to8BinaryDecoder"},
{"type":"4to16BinaryDecoder"}
],
"devices":[
{"type":"DC","id":"dev0","x":40,"y":128,"label":"DC"},
{"type":"Toggle","id":"dev1","x":184,"y":208,"label":"Toggle","state":{"on":true}},
{"type":"In","id":"dev2","x":256,"y":208,"label":"In B2"},
{"type":"Joint","id":"dev3","x":280,"y":112,"label":"Joint","state":{"direction":3}},
{"type":"NAND","id":"dev4","x":328,"y":56,"label":"NAND"},
{"type":"LED","id":"dev5","x":560,"y":56,"label":"LED Q"},
{"type":"Out","id":"dev6","x":416,"y":56,"label":"Out Q"},
{"type":"Out","id":"dev7","x":416,"y":200,"label":"Out ￢Q"},
{"type":"In","id":"dev8","x":256,"y":48,"label":"In B1"},
{"type":"Toggle","id":"dev9","x":184,"y":48,"label":"Toggle","state":{"on":true}},
{"type":"Joint","id":"dev10","x":520,"y":208,"label":"Joint","state":{"direction":0}},
{"type":"LED","id":"dev11","x":560,"y":200,"label":"LED ￢Q"}
],
"connectors":[
{"from":"dev1.in0","to":"dev0.out0"},
{"from":"dev2.in0","to":"dev1.out0"},
{"from":"dev3.in0","to":"dev10.out0"},
{"from":"dev4.in0","to":"dev8.out0"},
{"from":"dev4.in1","to":"dev3.out0"},
{"from":"dev6.in0","to":"dev4.out0"},
{"from":"dev8.in0","to":"dev9.out0"},
{"from":"dev9.in0","to":"dev0.out0"},
{"from":"dev10.in0","to":"dev7.out0"},
{"from":"dev11.in0","to":"dev10.out0"}
]
}