DAOKAI 5 stuks TCA9548A IIC Multiplexer implementatiekaart 400 kHz 1,8 V - 5 V 8 kanalen I2C communicatieschakelaar Ontwikkelingskaart met Reset voor Arduino

If you use I2C devices at all, you may have found that the address ranges are limited - you can't have more than one OLED device without a soldered modification (two addresses absolute maximum), or 8 GPIO devices, for example. And if you need long wires, then the capacitance limit of 400pF might be exceeded (I've found that with more than 25m of Cat5 or Cat6 cable you start to get errors). Or if you have more than six devices, all with 10k pull-up resistors, it could exceed the total pull-up current.If you're worried about any of these conditions, then the multiplexer (mux) is a possible solution. The mux enables you to split a single I2C bus into separate bus legs (I call them sub-buses) which can be connected or disconnected at will from the I2C master microcontroller. When one sub-bus is enabled and the others are disabled, it is as if the devices and wiring on the enabled sub-bus is the total extent of the bus network. So any addresses, capacitance, or pullups on the other sub-buses do not affect the communications. With the maximum of eight sub-buses on a multiplexer, you are allowed 400pF per sub-bus (3200pF total), and two OLED devices per sub-bus (16 total), and up to five sets of pull-ups per sub-bus (that's 40 devices before you have to start de-soldering the pull-up resistors)What's more, you can have up to eight multiplexers on one I2C bus, each switched independently. Again, if you only enable one sub-bus on each multiplexer at a time, then the figures above are multiplied by eight (25600pF maximum total capacitance, up to 64 devices with the same configured I2C address, and up to 320 sets of pull-up resistors). I challenge anyone to have requirements that get anywhere near these limits.I felt that the Multiplexer is such a useful tool for I2C that I've modified the DCC-EX Model Railway software so that it supports up to eight multiplexers seamlessly - the only software modification from the user's perspective is that, rather than specifying an I2C address as, say, 0x3c (OLED display), it is now specified as a triplet, e.g. {I2CMux_0, SubBus_3, 0x3c} - that's multiplexer 0 which has address 0x70, sub-bus 3, device address 0x3c. The I2C driver sends a one-byte command to the nominated multiplexer to enable that one sub-bus, and then talks directly with that OLED device. This type of address format will also enable use of multiple I2C buses where the hardware supports, but that's another story...

Working as designed

4チャンネルつかえました！

Die Module werden in einzelnen antistatischen Verpackungen ausgeliefert. Habe bisher eins benutzt, welches ohne Probleme funktioniert.

Unfortunately, these devices are not working!I did not get the I2C address of TCA9548A by scanning with ESP32.Used pull up resistors on SDA and SCL.On ESP32 with MicroPython not working.ON ESP32 with Arduino IDE not working.Bought 5 multiplexers, tested two of them.Tried reset with high and low.Used also EXP32S3 with all mentioned setups above, no I2C address received.Update one day later:Tested other three devices too, all of them work.Can't believe, in total 2 multiplexers failed, three are okay.What a waste of time...Put the seller on my black list.