<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><b style="color: #666666; font-size: 9pt; line-height: 1.5;"><span style="background-color: red; font-size: 12pt;"><span style="color: white;">&nbsp;블루투스 모듈 HC-06의 경우&nbsp;</span></span></b></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><br /></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체; font-size: 9pt; line-height: 1.5;">저렴하고 성능 좋아 많이 쓰이는 블루투스모듈 HC-06은 3.3V 입니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">잘 팔리는 모델은 아래 사진처럼 만지작거리기 편하도록 Pin Connector를 덧 붙여 다시 보드위에 조립한 형태입니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">그정도로는 왠지 허전 했던지 전원쪽에 조그만 레귤레이터를 붙여 입력 전원 범위를 3.6V - 6V 로 넓혀 놓았습니다만&nbsp;</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">시그널쪽은 그대로 입니다. &nbsp;<b>3.3V !!!</b></span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;"><b><br /></b></span></div>
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   <div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-ACNLffeqMfY/VyfzcRGMcII/AAAAAAAAAI8/2UHhlYoIv-wvcdUfI91CT8tdUI3VWUE9gCLcB/s1600/1.jpg" imageanchor="1" style="text-decoration-line: none; color: #888888; margin-left: 1em; margin-right: 1em;" target="_blank"><img border="0" src="https://3.bp.blogspot.com/-ACNLffeqMfY/VyfzcRGMcII/AAAAAAAAAI8/2UHhlYoIv-wvcdUfI91CT8tdUI3VWUE9gCLcB/s1600/1.jpg" style="border: 1px solid rgb(238, 238, 238); position: relative; padding: 5px; background-image: initial; background-position: initial; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; box-shadow: rgba(0, 0, 0, 0.1) 1px 1px 5px;" /></a></div>
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<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체; font-size: 9pt; line-height: 1.5;">3.3V 입력에 5V 출력을 연결하면 안됩니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">잠깐 쓰는 것 정도는 문제 없을지 몰라도 아까운 부품이 오래 오래 장수하길 기대하기는 곤란합니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">그러나 3.3V 출력을 5V 입력에 연결하는 것은 전혀 문제 없습니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><br /></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">우노 VCC는 +5V, 따라서 IO 도 모두 +5V 입니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">HC-06 Rx 측에 1K + 2K 저항 2개 가지고 분압하여 5V to 3.3V level shift 해 줍니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">Tx측은 그대로 연결하여도 됩니다.</span></div>
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   <div class="separator" style="clear: both; text-align: center;"><a href="https://4.bp.blogspot.com/-XiEFH0aFpvY/VyfzvO5cVjI/AAAAAAAAAJA/6mbIYWW4yZsaWlWhWqQUAzJZG4cDqRO4gCLcB/s1600/2.png" imageanchor="1" style="text-decoration-line: none; color: #888888; margin-left: 1em; margin-right: 1em;" target="_blank"><img border="0" height="208" src="https://4.bp.blogspot.com/-XiEFH0aFpvY/VyfzvO5cVjI/AAAAAAAAAJA/6mbIYWW4yZsaWlWhWqQUAzJZG4cDqRO4gCLcB/s320/2.png" width="320" style="border: 1px solid rgb(238, 238, 238); position: relative; padding: 5px; background-image: initial; background-position: initial; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; box-shadow: rgba(0, 0, 0, 0.1) 1px 1px 5px;" /></a></div>
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<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">0402(1015) &nbsp;저항을 connector pin사이에 붙입니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">작업이 간단하고 왠만해선 눈에 띄이지도 않아 미관상 좋으나 좀 허약해 보이는 게 단점이죠.</span></div>
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   <div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-mzCGeo1Cno4/Vyfz0nIKfyI/AAAAAAAAAJE/ocEWyu6JKMIyHcaqkTECmX_IflM9JsWFwCLcB/s1600/3.jpg" imageanchor="1" style="text-decoration-line: none; color: #888888; margin-left: 1em; margin-right: 1em;" target="_blank"><img border="0" height="150" src="https://3.bp.blogspot.com/-mzCGeo1Cno4/Vyfz0nIKfyI/AAAAAAAAAJE/ocEWyu6JKMIyHcaqkTECmX_IflM9JsWFwCLcB/s320/3.jpg" width="320" style="border: 1px solid rgb(238, 238, 238); position: relative; padding: 5px; background-image: initial; background-position: initial; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; box-shadow: rgba(0, 0, 0, 0.1) 1px 1px 5px;" /></a></div>
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<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;"><br /></span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><b style="color: #666666; font-size: 9pt; line-height: 1.5;"><span style="background-color: red; font-size: 12pt;"><span style="color: white;">&nbsp;3축 가속도 센서 MMA8452의 경우&nbsp;</span></span></b></div>
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<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체; font-size: 9pt; line-height: 1.5;">IIC로 연결되기 때문에 양방향입니다.</span></div>
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<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">SDA, SCL은 MMA8452Q Breakout Board 내에서 10K 로 3.3V에 pull-up 되어 있습니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;"><a href="https://cdn.sparkfun.com/datasheets/Sensors/Accelerometers/MMA8452Q_Breakout-v10.pdf" target="_blank" style="text-decoration-line: none; color: #888888;">https://cdn.sparkfun.com/datasheets/Sensors/Accelerometers/MMA8452Q_Breakout-v10.pdf</a></span></div>
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<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">단순히 저항가지고 분압할 수 있는 게 아닙니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">통상은 대략 난감한 경우이나&nbsp;</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">SDA, SCL에 330 저항 직렬로 삽입하는 걸로 간단히 처리하는 군요.</span></div>
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   <div class="separator" style="clear: both; text-align: center;"><a href="https://3.bp.blogspot.com/-Li8xKGg4DuQ/Vyfz3O54HZI/AAAAAAAAAJI/1b3Oke5c_SwMrl0bop4U57f8SBliOC3lACLcB/s1600/4.png" imageanchor="1" style="text-decoration-line: none; color: #888888; margin-left: 1em; margin-right: 1em;" target="_blank"><img border="0" height="203" src="https://3.bp.blogspot.com/-Li8xKGg4DuQ/Vyfz3O54HZI/AAAAAAAAAJI/1b3Oke5c_SwMrl0bop4U57f8SBliOC3lACLcB/s320/4.png" width="320" style="border: 1px solid rgb(238, 238, 238); position: relative; padding: 5px; background-image: initial; background-position: initial; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; box-shadow: rgba(0, 0, 0, 0.1) 1px 1px 5px;" /></a></div>
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<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">역시 0402(1015) &nbsp;저항으로 connector pin사이를 연결합니다.</span></div>
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   <div class="separator" style="clear: both; text-align: center;"><a href="https://1.bp.blogspot.com/-L0kP8DhTQfk/Vyfz5-99jWI/AAAAAAAAAJM/9z6yPrVnyB43FeB8fx6Jv9a19Qt_li1IACLcB/s1600/5.jpg" imageanchor="1" style="text-decoration-line: none; color: #888888; margin-left: 1em; margin-right: 1em;" target="_blank"><img border="0" height="320" src="https://1.bp.blogspot.com/-L0kP8DhTQfk/Vyfz5-99jWI/AAAAAAAAAJM/9z6yPrVnyB43FeB8fx6Jv9a19Qt_li1IACLcB/s320/5.jpg" width="301" style="border: 1px solid rgb(238, 238, 238); position: relative; padding: 5px; background-image: initial; background-position: initial; background-size: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; box-shadow: rgba(0, 0, 0, 0.1) 1px 1px 5px;" /></a></div>
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<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">Sparkfun 측에서는 이 팁에 대해 이렇게 설명합니다.</span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;"><span style="color: #3a32c3;">"MMA8452Q 내에서 SDA, SCL에 ESD(Electro Static Discharge) diode가 걸려있어 &nbsp;3.3V 이상 올라가지 못한다.</span></span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;"><span style="color: #3a32c3;">&nbsp;더해서 Arduino 측 SDA, SCL은 ATmega 내부에서 5V pull-up 되었으나 이 저항이 3.3V 로 pull-up 하는 10K 보다&nbsp;</span></span></div>
<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;"><span style="color: #3a32c3;">&nbsp;상당히 큰 값이어서 3.3V가 유지된다. "&nbsp;</span></span></div>
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<div style="background-color: #ffffff; color: #333333; font-family: 돋움, dotum, Helvetica, sans-serif; line-height: 16.8px; list-style: none; margin: 0px; padding: 0px;"><span style="font-family: 굴림체;">그렇군요. 실제 테스터로 측정해 보면 확인이 됩니다.</span></div>