Description
The TCA9548A is an I2C multiplexer that allows up to 8 devices with the same I2C address to be hooked up to an MCU or permits up to 8 separate I2C buses to be controlled.
Features
- 1 to 8 bi-directional I2C switches
- Allows level translation between individual buses
- I2C control interface
- 3.3 & 5V operation
One of the great things about I2C is that multiple devices can be hooked up to the same I2C bus if their addresses are unique. In some cases, a part may have a fixed address and therefore it is impossible to use more than one of the devices on the same bus or in another case, two different devices may happen to have the same fixed I2C address which also creates a bus conflict.
You may also want to separate a large number of devices on a single I2C bus into several smaller buses due to loading concerns or for bus isolation.
The TCA9548A addresses those issues by allowing a single master I2C bus to address up to 8 different slave I2C buses individually or in any combination. The multiplexer is given a command as to which bus(es) to use and then any future I2C communications will continue to use that bus configuration until commanded to use a different one.
The module uses the 24-pin TCA9548A 8-channel I2C multiplexer chip. It supports I2C bus speeds up to 400kHz and allows level translation between 1.8V, 2.5V, 3.3V and 5V buses.
Specifications
| Operating Rating | Vcc | 1.65 – 5.5V (3.3 or 5V typ) |
| Clock Frequency | 0 – 400kHz | |
| Dimensions | L x W (PCB) | 31 x 21mm (1.2? x 0.83?) |
Module Connections
The board has two 12-pin male headers which give access to all the chip pins. All inputs are 5V tolerant
1 x 12 Header (left)
- VIN = Supports 1.65V to 5.5V power (3.3 or 5V typical)
- GND = Ground. Should be common with MCU
- SDA = Master I2C Data
- SCL = Master I2C Clock
- RST = Reset active LOW. Pulled HIGH on module with 10K resistor by default
- A0 = Master I2C Address pin 0
- A1 = Master I2C Address pin 1
- A2 = Master I2C Address pin 2
- SD0 = Slave I2C Bus 0 – SDA
- SC0 = Slave I2C Bus 0 – SCL
- SD1 = Slave I2C Bus 1 – SDA
- SC1 = Slave I2C Bus 1 – SCL
1 x 12 Header (right)
- SC7 = Slave I2C Bus 7 – SDA
- SD7 = Slave I2C Bus 7 – SCL
- SC6 = Slave I2C Bus 6 – SDA
- SD6 = Slave I2C Bus 6 – SCL
- SC5 = Slave I2C Bus 5 – SDA
- SD5 = Slave I2C Bus 5 – SCL
- SC4 = Slave I2C Bus 4 – SDA
- SD4 = Slave I2C Bus 4 – SCL
- SC3 = Slave I2C Bus 3 – SDA
- SD3 = Slave I2C Bus 3 – SCL
- SC2 = Slave I2C Bus 2 – SDA
- SD2 = Slave I2C Bus 2 – SCL
Package List
- TCA9548A Module
- Qty 2 – 12-pin male header strips
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