CJMCU-9548 TCA9548A 1-to-8 I2C 8 Channel IIC Multiple Extensions Development Board

Description:

The TCA9548A device has eight bidirectional translating switches that can be controlled through the I²C bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Any individual SCn/SDn channel or combination of channels can be selected, determined by the contents of the programmable control register. These downstream channels can be used to resolve I²C slave address conflicts. For example, if eight identical digital temperature sensors are needed in the application, one sensor can be connected at each channel: 0-7.

The system master can reset the TCA9548A in the event of a time-out or other improper operation by asserting a low in the RESET input. Similarly, the power-on reset deselects all channels and initializes the I²C/SMBus state machine. Asserting RESET causes the same reset and initialization to occur without powering down the part. This allows recovery should one of the downstream I²C buses get stuck in a low state.

The pass gates of the switches are constructed so that the VCC pin can be used to limit the maximum high voltage, which is passed by the TCA9548A. Limiting the maximum high voltage allows the use of different bus voltages on each pair, so that 1.8-V, 2.5-V or 3.3-V parts can communicate with 5-V parts, without any additional protection. External pullup resistors pull the bus up to the desired voltage level for each channel. All I/O pins are 5-V tolerant.

Features:

• 1-to-8 Bidirectional Translating Switches
• I²C Bus and SMBus Compatible
• Active-Low Reset Input
• Three Address Pins, Allowing up to Eight TCA9548A Devices on the I²C Bus
• Channel Selection Through an I²C Bus, In Any Combination
• Power Up With All Switch Channels Deselected
• Low R_ON Switches
• Allows Voltage-Level Translation Between 1.8-V, 2.5-V, 3.3-V, and 5-V Buses
• No Glitch on Power Up
• Supports Hot Insertion
• Low Standby Current
• Operating Power-Supply Voltage Range of
  1.65 V to 5.5 V
• 5-V Tolerant Inputs
• 0- to 400-kHz Clock Frequency
• Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
• ESD Protection Exceeds JESD 22
  • ±2000-V Human-Body Model (A114-A)
  • 200-V Machine Model (A115-A)
  • ±1000-V Charged-Device Model (C101)

Applicaties

• Servers
• Routers (Telecom Switching Equipment)
• Factory Automation
• Products With I²C Slave Address Conflicts (Such as Multiple, Identical Temperature Sensors)

Control Multiple OLED Displays—TCA9548A I2C Multiplexer

Source code:

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Select I2C BUS
void TCA9548A(uint8_t bus){
  Wire.beginTransmission(0x70);  // TCA9548A address
  Wire.write(1 << bus);          // send byte to select bus
  Wire.endTransmission();
  Serial.print(bus);
}
 
void setup() {
  Serial.begin(115200);

  // Start I2C communication with the Multiplexer
  Wire.begin();

  // Init OLED display on bus number 2
  TCA9548A(2);
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  } 
  // Clear the buffer
  display.clearDisplay();

  // Init OLED display on bus number 3
  TCA9548A(3);
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  } 
  // Clear the buffer
  display.clearDisplay();

  // Init OLED display on bus number 4
  TCA9548A(4);
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  } 
  // Clear the buffer
  display.clearDisplay();

  // Init OLED display on bus number 5
  TCA9548A(5);
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  } 
  // Clear the buffer
  display.clearDisplay();

  // Write to OLED on bus number 2
  TCA9548A(2);
  display.clearDisplay();
  display.setTextSize(8);
  display.setTextColor(WHITE);
  display.setCursor(45, 10);
  // Display static text
  display.println("1");
  display.display(); 

  // Write to OLED on bus number 3
  TCA9548A(3);
  display.clearDisplay();
  display.setTextSize(8);
  display.setTextColor(WHITE);
  display.setCursor(45, 10);
  // Display static text
  display.println("2");
  display.display(); 
  
  // Write to OLED on bus number 4
  TCA9548A(4);
  display.clearDisplay();
  display.setTextSize(8);
  display.setTextColor(WHITE);
  display.setCursor(45, 10);
  // Display static text
  display.println("3");
  display.display(); 
  
  // Write to OLED on bus number 5
  TCA9548A(5);
  display.clearDisplay();
  display.setTextSize(8);
  display.setTextColor(WHITE);
  display.setCursor(45, 10);
  // Display static text
  display.println("4");
  display.display(); 
}
 
void loop() {
  
}

Documents:

• Adafruit TCA9548A Overview Adafruit