How to Use SC16IS752: Examples, Pinouts, and Specs

The SC16IS752 is a dual-channel I2C/SPI to UART bridge designed to facilitate serial communication between microcontrollers and other devices. It provides a high-speed UART interface with programmable baud rates, making it suitable for a wide range of embedded system applications. The component supports both I2C and SPI protocols, offering flexibility in communication interfaces.

• Expanding UART ports in microcontroller-based systems
• Communication with serial devices such as GPS modules, sensors, or modems
• Industrial automation and control systems
• IoT devices requiring multiple UART interfaces
• Data logging and monitoring systems

• Supply Voltage (Vcc): 2.5V to 3.3V (5V tolerant I/O)
• Communication Protocols: I2C (up to 400 kHz) and SPI (up to 4 Mbps)
• UART Channels: 2 (dual-channel)
• Baud Rate: Programmable up to 5 Mbps
• FIFO Buffer: 64 bytes per channel (TX and RX)
• GPIO Pins: 8 configurable GPIOs
• Operating Temperature Range: -40°C to +85°C
• Package: TSSOP-28, HVQFN-32

1. Power Supply: Connect the VCC pin to a 3.3V power source and the VSS pins to ground.
2. Clock Source: Use an external crystal oscillator (e.g., 14.7456 MHz) connected to XTAL1 and XTAL2, or provide an external clock signal to XTAL1.
3. Communication Protocol Selection:
   • For I2C: Connect SCL and SDA to the microcontroller's I2C pins. Use A0, A1, and A2 to set the I2C address.
   • For SPI: Connect SCLK, MOSI, MISO, and CS to the microcontroller's SPI pins.
4. UART Connections: Connect TXA/RXA and TXB/RXB to the respective UART devices. Use RTS and CTS for hardware flow control if needed.
5. GPIO Configuration: Configure GPIO pins as inputs or outputs as required by your application.

• Use pull-up resistors (typically 4.7kΩ) on the I2C lines (SCL and SDA).
• Decouple the power supply with a 0.1 µF capacitor close to the VCC pin.
• Ensure proper termination for SPI lines to avoid signal integrity issues.
• Configure the baud rate and other UART settings via the SC16IS752's internal registers.
• Use the RESET pin to initialize the device during power-up or after a fault condition.

#include <Wire.h>

// SC16IS752 I2C address (A0, A1, A2 = 0)
#define SC16IS752_ADDR 0x48

void setup() {
  Wire.begin(); // Initialize I2C communication
  Serial.begin(9600); // Initialize Serial Monitor for debugging

  // Initialize SC16IS752
  Wire.beginTransmission(SC16IS752_ADDR);
  Wire.write(0x03); // Write to the LCR (Line Control Register)
  Wire.write(0x80); // Enable access to the baud rate registers
  Wire.endTransmission();

  Wire.beginTransmission(SC16IS752_ADDR);
  Wire.write(0x00); // DLL (Divisor Latch LSB)
  Wire.write(0x1A); // Set baud rate to 9600 (assuming 14.7456 MHz clock)
  Wire.endTransmission();

  Wire.beginTransmission(SC16IS752_ADDR);
  Wire.write(0x01); // DLM (Divisor Latch MSB)
  Wire.write(0x00); // Set baud rate to 9600
  Wire.endTransmission();

  Wire.beginTransmission(SC16IS752_ADDR);
  Wire.write(0x03); // Write to the LCR again
  Wire.write(0x03); // 8 data bits, no parity, 1 stop bit
  Wire.endTransmission();

  Serial.println("SC16IS752 initialized.");
}

void loop() {
  // Example: Send data to UART channel A
  Wire.beginTransmission(SC16IS752_ADDR);
  Wire.write(0x00); // THR (Transmit Holding Register) for channel A
  Wire.write('H');  // Send character 'H'
  Wire.endTransmission();

  delay(1000); // Wait 1 second
}

1. No Communication with the SC16IS752:

   • Verify the I2C or SPI connections and ensure the correct protocol is selected.
   • Check the I2C address or SPI chip select configuration.
   • Ensure pull-up resistors are present on the I2C lines.

2. UART Data Loss or Corruption:

   • Verify the baud rate and UART settings match between the SC16IS752 and the connected device.
   • Use hardware flow control (RTS/CTS) if the connected device supports it.

3. Device Not Responding After Power-Up:

   • Ensure the RESET pin is properly initialized during startup.
   • Check the power supply voltage and decoupling capacitors.

4. GPIO Pins Not Functioning:

   • Verify the GPIO pins are correctly configured as inputs or outputs.
   • Check for conflicts with other connected devices.

• Can the SC16IS752 operate at 5V?

  • The SC16IS752 is designed for 3.3V operation but has 5V-tolerant I/O pins.

• What is the maximum UART baud rate?

  • The SC16IS752 supports baud rates up to 5 Mbps.

• Can I use both I2C and SPI simultaneously?

  • No, the SC16IS752 can operate in either I2C or SPI mode, but not both at the same time.