How to Use SC16IS752: Examples, Pinouts, and Specs

The SC16IS752, manufactured by NXP, 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 configurable baud rates and supports both I2C and SPI protocols, making it a versatile solution for embedded systems. This component is particularly useful in applications requiring multiple UART interfaces but limited microcontroller resources.

• Industrial automation and control systems
• IoT devices requiring UART communication
• GPS modules and GSM modems
• Data logging and telemetry systems
• Multi-protocol communication bridges

• 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 UART)
• Baud Rate: 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

The SC16IS752 is available in multiple packages. Below is the pin configuration for the TSSOP-28 package:

1. Power Supply: Connect the VCC pin to a 3.3V power source and the VSS pin to ground.
2. Communication Protocol Selection:
   • For I2C: Connect the SCL and SDA pins to the I2C bus of the microcontroller. Use A0, A1, and A2 to set the I2C address.
   • For SPI: Connect SCLK, MOSI, MISO, and CS (A0) to the SPI bus of the microcontroller.
3. UART Connections: Connect the TXD and RXD pins of each UART channel to the corresponding devices.
4. GPIO Configuration: Use the GPIO pins as needed for additional control or status signals.
5. Clock Source: Connect a crystal oscillator to XTAL1 and XTAL2, or provide an external clock signal to XTAL1.
6. Interrupt Handling: Connect the IRQ pin to a microcontroller interrupt pin for efficient event handling.

• Ensure proper pull-up resistors (typically 4.7kΩ) are used on the I2C bus lines (SCL and SDA).
• For SPI communication, ensure the clock polarity and phase settings match between the SC16IS752 and the microcontroller.
• Configure the baud rate and UART settings (e.g., parity, stop bits) to match the connected devices.
• Use decoupling capacitors (e.g., 0.1µF) near the VCC pin to stabilize the power supply.

#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
  
  // Initialize SC16IS752
  Wire.beginTransmission(SC16IS752_ADDR);
  Wire.write(0x03); // Write to the FCR (FIFO Control Register)
  Wire.write(0x07); // Enable FIFO, clear TX/RX FIFO
  Wire.endTransmission();
  
  Serial.println("SC16IS752 Initialized");
}

void loop() {
  // Example: Send data to UART0
  Wire.beginTransmission(SC16IS752_ADDR);
  Wire.write(0x00); // THR (Transmit Holding Register) for UART0
  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 configuration (A0, A1, A2 pins).
   • Ensure pull-up resistors are present on the I2C lines.

2. UART Data Loss:

   • Ensure the baud rate and UART settings match between the SC16IS752 and the connected device.
   • Check if the FIFO buffer is full and handle interrupts appropriately.

3. Interrupts Not Triggering:

   • Verify the IRQ pin is connected to the correct microcontroller interrupt pin.
   • Ensure the interrupt enable registers are configured correctly.

• Use an oscilloscope or logic analyzer to monitor I2C/SPI signals and UART data lines.
• Test the SC16IS752 with a simple loopback setup (connect TXD to RXD) to verify UART functionality.
• Refer to the SC16IS752 datasheet for detailed register descriptions and configuration options.