ST16C550CQ48-F

The ST16C550CQ48-F is STMicroelectronics’ UART core that is compatible with the classic 16C550/8250 serial interface, implemented in a 48-pin CQFP package. It provides one fully programmable UART to convert between CPU data and serial RS-232/TTL data for embedded systems.
Key points:
- Standard UART registers: RBR/THR, IER, IIR, LCR, MCR, LSR, MSR, SCR.
- Baud rate: programmable baud-rate generator (clock-divider based).
- Data format: 5–8 data bits, 1 or 2 stop bits, parity options (none/even/odd/mark/space).
- Interrupt-driven: RX/TX and line-status interrupts for efficient operation.
- FIFO/buffering: often includes a FIFO to reduce CPU interrupts (where available).
- Interfaces: works with RS-232 transceivers or TTL-level serial, plus support for hardware (RTS/CTS) and software flow control in various configurations.
- Applications: adds reliable serial communication to microcontrollers/CPUs, bridging to PCs, modems, sensors, etc.
Note: exact FIFO, flow-control options, and clock requirements depend on the specific revision and clocking used.

Key features of ST16C550CQ48-F (48-pin CQFP, lead-free):
- One ST16C550-compatible asynchronous UART core (single channel)
- Data formats: 5–8 data bits, 1 or 2 stop bits, parity (none, odd, even, mark, space)
- Programmable baud-rate generator using an external clock
- Interrupts: Receiver Data Available, Transmitter Holding Register Empty, and Receiver Line Status (maskable)
- Hardware flow control: RTS/CTS; DTR/DSR support
- Software flow control: XON/XOFF
- RS-232 signal compatibility (RXD, TXD, RTS/CTS, DTR/DSR, RI, DCD)
- Flexible clock and I/O levels (external clock input; compatible with common logic voltages)
- 48-pin CQFP package; RoHS-compliant (Pb-free)
- Industrial temperature capability (typical for embedded UARTs)
Note: For exact voltage ranges, clock specs, timing parameters, and pinout details, consult the official datasheet.

CQ48-F indicates a 48‑pin Quad Flat Package (CQFP), lead‑free variant.

- Pin count: 48-pin (CQ48) package, typically a 48-pin QFP.
- Function: ST16C550CQ48-F is a 16C550-compatible single-channel UART (universal asynchronous receiver/transmitter) for RS-232 serial communication. It provides the standard serial I/O (TXD, RXD, RTS, CTS, DTR, DSR, DCD, RI), interrupt/status registers and a baud-rate generator; requires external line drivers/transceivers for RS-232 signaling.

- Manufacturer: STMicroelectronics (STMicroelectronics N.V.)
- What kind of company: A multinational semiconductor company that designs and manufactures integrated circuits, sensors, microcontrollers, and other electronic components.

Applications include:
- Embedded systems and microcontrollers for RS-232/RS-485 serial links
- Industrial automation (PLC/HMI, sensors) requiring a reliable UART
- Modems and telecom equipment serial interfaces
- Test and measurement instruments and data loggers with serial consoles
- Point-of-sale terminals and peripheral devices
- Networking gear console/management ports for firmware/debugging

Equivalents are other 16C550-compatible UARTs, e.g.:
- NS16550 / NS16550A (National Semiconductor)
- XR16C550 (Exar)
- SC16C550 (SMSC)
- TL16C550 (Texas Instruments)
These are pin-compatible with ST16C550CQ48-F and share the same register set and operation.