{"product_id":"adafruit-tca4307-hot-swap-i2c-buffer-with-stuck-bus-recovery-stemma-qt-qwiic","title":"Adafruit TCA4307 Hot-Swap I2C Buffer with Stuck Bus Recovery","description":"\u003cp\u003eAs Adafruit have been adding STEMMA QT connectors to their breakouts and dev boards, folks have been really enjoying the simplicity and speed of plugging in I2C sensors and devices for quick iteration and design.\u003c\/p\u003e\n\u003cp\u003eThat's all good, but I2C wasn't really designed for hot-plugging. You're kinda supposed to have everything connected once on boot and never mess with it - I2C was specified for on-board connections. And, folks who have experimented with hot-plugging I2C devices eventually have discovered that if you plug in or unplug at the wrong moment you can cause the bus to hang due to an extra SCL pulse or an unexpected capacitive load.\u003c\/p\u003e\n\u003cp\u003eThe \u003cstrong\u003eAdafruit TCA4307 Hot-Swap I2C Buffer\u003c\/strong\u003e breakout here solves that problem. It's specifically designed to take a non-hot-swap protocol (I2C) and protect the controller from wayward peripherals messing with the bus during attach\/detach.\u003c\/p\u003e\n\u003cp\u003eUsage is super simple. Connect the left side (IN) to your main board controller - Arduino, Raspberry Pi, Feather, etc. Then connect any I2C sensors you like to OUT side. Power is connected through - this isn't a power isolator, just a bus buffer. You can use 2.3 to 5.5V DC power and logic levels.\u003c\/p\u003e\n\u003cp\u003eThe chip can handle up to 400KHz I2C clock rates and even has stuck bus recovery: it automatically disconnects the bus if it detects either SDAOUT or SCLOUT are low for about 40 ms. Once the bus is disconnected, the device automatically generates up to 16 pulses on SCLOUT to attempt to reset the device which is holding the bus low.\u003c\/p\u003e\n\u003cp\u003eThere's also an extra ENable pin, if you want to disconnect the in and out sides, and a READY pin that will let you know if the peripheral is buffer-connected to the controller (and is safe to attempt communication with)\u003c\/p\u003e\n\u003cp\u003eTo get you going fast, Adafruit spun up a custom-made PCB in the \u003ca href=\"\/en-eu\/collections\/stemma-qt\" target=\"_blank\" rel=\"noopener noreferrer\"\u003eSTEMMA QT form factor\u003c\/a\u003e, making it easy to interface with. The \u003ca href=\"https:\/\/learn.adafruit.com\/introducing-adafruit-stemma-qt\/what-is-stemma-qt\" target=\"_blank\" rel=\"noopener noreferrer\"\u003eSTEMMA QT connectors\u003c\/a\u003e on either side are compatible with the \u003ca href=\"\/en-eu\/collections\/qwiic\" target=\"_blank\" rel=\"noopener noreferrer\"\u003eSparkFun Qwiic\u003c\/a\u003e I2C connectors. This allows you to make solderless connections between your development board and the TCA4307 or to chain it with a wide range of other sensors and accessories using a compatible cable. \u003ca href=\"\/en-eu\/products\/jst-sh-cable-qwiic-stemma-qt-compatible\" target=\"_blank\" rel=\"noopener noreferrer\"\u003eQT Cable is not included, but we have a variety in the shop.\u003c\/a\u003e\u003c\/p\u003e\n\u003ch2\u003eTECHNICAL DETAILS\u003c\/h2\u003e\n\u003cp\u003eProduct Dimensions: 25.4mm x 17.8mm x 4.5mm \/ 1.0\" x 0.7\" x 0.2\"\u003c\/p\u003e\n\u003cp\u003eProduct Weight: 1.7g \/ 0.1oz\u003c\/p\u003e","brand":"Adafruit","offers":[{"title":"Default Title","offer_id":39403533828179,"sku":"ADA5159","price":5.95,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0174\/1800\/products\/5159-01.jpg?v=1626711883","url":"https:\/\/shop.pimoroni.com\/en-eu\/products\/adafruit-tca4307-hot-swap-i2c-buffer-with-stuck-bus-recovery-stemma-qt-qwiic","provider":"Pimoroni Ltd","version":"1.0","type":"link"}