Manufacturer: EXAR
Part Number: ST16C554DCQ64-F
#### Key Specifications:
- Description: Quad UART with 16-byte FIFOs
- Interface Type: UART (Universal Asynchronous Receiver/Transmitter)
- Number of Channels: 4 (Quad)
- FIFO Depth: 16 bytes per channel
- Data Rate: Up to 1.5 Mbps
- Operating Voltage: 3.3V or 5V
- Package Type: LQFP-64
- Operating Temperature Range: Commercial (0°C to +70°C) or Industrial (-40°C to +85°C)
#### Features:
- Independent baud rate generators for each UART
- Programmable auto-flow control (CTS/RTS)
- Infrared (IrDA) encoder/decoder support
- Sleep mode for reduced power consumption
- Software-selectable baud rates
- Industrial temperature range option available
- 3.3V and 5V compatible I/O
This UART IC is designed for high-performance serial communication applications, supporting multiple channels with deep FIFOs for efficient data buffering.
# ST16C554DCQ64-F: Practical Applications, Design Pitfalls, and Implementation Considerations
## Practical Application Scenarios
The ST16C554DCQ64-F, manufactured by EXAR, is a quad UART (Universal Asynchronous Receiver/Transmitter) IC designed for high-performance serial communication in embedded systems. Its key applications include:
1. Industrial Automation
- Used in PLCs (Programmable Logic Controllers) and industrial control systems for multi-channel serial communication with sensors, actuators, and HMIs.
- Supports RS-232/422/485 protocols, enabling long-distance communication in noisy environments.
2. Telecommunications Equipment
- Facilitates modem communication, multiplexing, and legacy telephony interfaces.
- The FIFO buffers (64-byte depth) reduce CPU overhead in high-throughput systems.
3. Point-of-Sale (POS) Terminals
- Enables connectivity with barcode scanners, receipt printers, and payment terminals via multiple UART channels.
4. Embedded Computing
- Ideal for multi-port serial expansion in single-board computers (SBCs) and legacy device interfacing.
5. Medical Devices
- Supports reliable data transmission in diagnostic equipment where real-time serial communication is critical.
## Common Design-Phase Pitfalls and Avoidance Strategies
1. Incorrect Clock Configuration
- Pitfall: Mismatched baud rates due to improper clock source selection or divider settings.
- Solution: Verify clock input (3.3V or 5V compatibility) and use precise crystal oscillators. Calculate baud rate divisors using the formula provided in the datasheet.
2. FIFO Buffer Underflow/Overflow
- Pitfall: Data loss occurs if FIFOs are not managed correctly.
- Solution: Enable FIFO interrupts (IER register) and implement robust ISR (Interrupt Service Routine) handlers to monitor thresholds.
3. Noise in RS-485 Networks
- Pitfall: Signal integrity issues in long-distance RS-485 mode.
- Solution: Implement proper termination resistors (120Ω), use twisted-pair cabling, and enable built-in fail-safe biasing.
4. Power Supply Decoupling Neglect
- Pitfall: Unstable operation due to insufficient decoupling capacitors.
- Solution: Place 0.1µF ceramic capacitors close to VCC pins and follow PCB layout best practices for analog/digital ground separation.
5. Register Initialization Errors
- Pitfall: UART channels malfunction if control registers are not configured sequentially.
- Solution: Follow the initialization sequence in the datasheet (e.g., LCR → FCR → IER) and verify register writes via read-back checks.
## Key Technical Considerations for Implementation
1. Voltage Compatibility
- The ST16C554DCQ64-F operates at 5V but is tolerant to 3.3V logic levels. Ensure level-shifting if interfacing with modern low-voltage MCUs.
2. Interrupt Handling
- Prioritize interrupt-driven designs over polling to maximize efficiency. The component supports prioritized interrupts