{"product_id":"cjmcu-tca9548a-i2c-8-channel-multiple-extensions-development-board","title":"CJMCU TCA9548A I2C 8 Channel Multiple Extensions Development Board","description":"\u003cp\u003eYou just found the perfect I2C sensor, and you want to wire up two, three, or more of them to your Arduino. When you realize \"Oh no, this chip has a fixed I2C address, and from what I know about I2C; you cannot have two devices with the same address on the same SDA\/SCL pins\". Are you out of luck? You would be if you don't have this cool CJMCU TCA9548A I2C 8 Channel Multiple Extensions Development Board.\u003c\/p\u003e\n\u003cp\u003eThe CJMCU TCA9548A I2C 8 Channel Multiple Extensions Development Board is interesting in that it has an I2C address (0x70 by default) - and you basically send it a command to tell it which I2C multiplexed output you want to talk to, then you can address the board you want to address.\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/robu.in\/\" rel=\"noopener noreferrer\" target=\"_blank\"\u003eRobu.in\u003c\/a\u003e\u003cspan\u003e have a different kind of breakout boards; for more boards \u003c\/span\u003e\u003ca href=\"https:\/\/robu.in\/product-category\/breakout-board\/\" rel=\"noopener noreferrer\" target=\"_blank\"\u003e\u003cstrong\u003eClick here\u003c\/strong\u003e\u003c\/a\u003e\u003cspan\u003e. \u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eNote : PCA9548A on board working remains same.\u003c\/strong\u003e\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch4\u003eSpecification and Features :\u003c\/h4\u003e\n\u003col\u003e\n\u003cli\u003e1-to-8 Bidirectional Translating Switches.\u003c\/li\u003e\n\u003cli\u003eSupports Hot Insertion.\u003c\/li\u003e\n\u003cli\u003eLow Standby Current.\u003c\/li\u003e\n\u003cli\u003e1-to-8 Bidirectional Translating Switches.\u003c\/li\u003e\n\u003cli\u003eActive-Low Reset Input.\u003c\/li\u003e\n\u003cli\u003ePower Up With All Switch Channels Deselected.\u003c\/li\u003e\n\u003cli\u003eI2C Bus and SMBus Compatible.\u003c\/li\u003e\n\u003cli\u003e5-V Tolerant Inputs.\u003c\/li\u003e\n\u003cli\u003eLatch-Up Performance Exceeds 100 mA Per JESD 78, Class II.\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003chr\u003e\n\u003ch3\u003e\u003cspan\u003ePin Description : \u003c\/span\u003e\u003c\/h3\u003e\n\u003ch4\u003e\u003cspan\u003ePower Pins:\u003c\/span\u003e\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eVin\u003c\/strong\u003e - this is the power pin. Since the sensor chip uses 3-5 VDC. To power, the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V micro like Arduino, use 5V.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGND\u003c\/strong\u003e - common ground for power and logic.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003e\u003cspan\u003eI2C Control-Side pins : \u003c\/span\u003e\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSCL \u003c\/strong\u003e- this is the I2C clock pin for the chip itself, connect to your microcontrollers I2C clock line.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSDA \u003c\/strong\u003e- this is the I2C data pin for the chip itself, connect to your microcontrollers I2C data line.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRST \u003c\/strong\u003e- this is the reset pin, for resetting the multiplexer chip. Pulled high by default, connect to ground to reset\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA0\u003c\/strong\u003e \u003cstrong\u003eA1 A2\u003c\/strong\u003e - these are the address selection pins for the multiplexer. By default, the multiplexer is at address \u003cspan\u003e0x70\u003c\/span\u003e and these three pins are pulled low. Connect them to Vin to set the address to 0x71 - 0x77.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA0\u003c\/strong\u003e is the lowest-significant bit (if it is pulled high, it will increase the address by 1).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA1\u003c\/strong\u003e is the 2nd-lowest-significant bit (if it is pulled high, it will increase the address by 2).\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eA2\u003c\/strong\u003e is the 3rd-lowest-significant bit (if it is pulled high, it will increase the address by 4).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cspan\u003eI2C Multiplexed-Side pins:\u003c\/span\u003e\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSDx\u003c\/strong\u003e and \u003cstrong\u003eSCx\u003c\/strong\u003e:  There are 8 sets of \u003cstrong\u003eSDx\u003c\/strong\u003e and \u003cstrong\u003eSCx\u003c\/strong\u003e pins, from \u003cstrong\u003eSD0\/SC0\u003c\/strong\u003e to \u003cstrong\u003eSD7\/SC7\u003c\/strong\u003e. These are the multiplexed pins. Each one is a completely separate I2C bus set. So you have 8 I2C devices with identical addresses, as long as they are on one I2C bus each.\u003c\/li\u003e\n\u003cli\u003eThese pins do not have any pullups installed, so if you are using a chip or breakout without I2C pull-ups be sure to add them! Nicely, you can have \u003cstrong\u003eVin\u003c\/strong\u003e be 3.3V and have these pins pulled up to 5V (that is, they are 5V compliant).\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003cp\u003e\u003cstrong\u003eProgram : \u003c\/strong\u003e\u003cspan\u003e We suggest using this little helper to help you select the port #define TCAADDR 0x70 void tcaselect(uint8_t i) { if (i \u0026gt; 7) return; Wire.beginTransmission(TCAADDR); Wire.write(1 \u0026lt;\u0026lt; i); Wire.endTransmission(); } You can then call tcaselect(0) thru tcaselect(7) to set up the multiplexer. \u003c\/span\u003e\u003cstrong\u003eNote\u003c\/strong\u003e\u003cspan\u003e that you if you happen to have I2C devices with I2C address 0x70, you will need to short one of the \u003c\/span\u003e\u003cstrong\u003eAddr\u003c\/strong\u003e\u003cspan\u003e pins on the TCA9548 breakout to \u003c\/span\u003e\u003cstrong\u003eVin\u003c\/strong\u003e\u003cspan\u003e in order to make it not conflict. Given that you can have 0x70 thru 0x77, just find one that's free and you're good to go. \u003c\/span\u003e\u003cspan\u003e\u003cstrong\u003eNote : Product may vary in two variants TCA9548A \u0026amp;  PCA9548A\u003c\/strong\u003e\u003c\/span\u003e\u003cspan\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch4\u003ePackage Includes :\u003c\/h4\u003e\n\u003cp\u003e\u003cspan\u003e1 x CJMCU TCA9548A I2C 8 Channel Multiple extensions development board. 2 x Header set ( Without Soldered).\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eSpecification:\u003c\/span\u003e\u003c\/p\u003e\n\u003ctable class=\"specs-table\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eNo. of Channels:\u003c\/td\u003e\n\u003ctd\u003e8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel No:\u003c\/td\u003e\n\u003ctd\u003eCJMCU TCA9548A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight (g):\u003c\/td\u003e\n\u003ctd\u003e4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShipping Weight\u003c\/td\u003e\n\u003ctd\u003e0.005 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShipping Dimensions\u003c\/td\u003e\n\u003ctd\u003e4 × 4 × 3 cm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e","brand":"Jaideep Robotics","offers":[{"title":"Default Title","offer_id":46441650749613,"sku":"421239","price":59.0,"currency_code":"INR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0773\/7638\/9293\/files\/download-2026-06-28T152558.632.avif?v=1782640567","url":"https:\/\/jaideeprobotics.com\/products\/cjmcu-tca9548a-i2c-8-channel-multiple-extensions-development-board","provider":"Jaideep Robotics ","version":"1.0","type":"link"}