- Capable of running all existing 16450 and 16550a software
- Fully Synchronous design. All inputs and outputs are based on rising edge of clock
- In FIFO mode, the transmitter and receiver are each buffered with 16 byte FIFOs to reduce the number of interrupts presented to the CPU
- Adds or deletes standard asynchronous communication bits (start, stop and parity) to or from the serial data
- Independently controlled transmit, receive, line status and data set interrupts
- Programmable baud generator divides any input clock by 1 to (2**16 - 1) and generates the 16 x clock
- Modem control functions (CTSn, RTSn, DSRn, DTRn, RIn, and DCDn)
- Fully programmable serial interface characteristics:
- 5, 6, 7, or 8 bit characters
- Even, odd, or no-parity bit generation and detection
- 1, 1½, or 2 stop bit generation
- Baud generation
- False start bit detection
- Complete status register
- Internal diagnostic capabilities: loopback controls for communications link fault isolation
- Full prioritized interrupt system controls
UART IP Core H16550S Synchronous 16550 UART with FIFO Core
The H16550S is a standard UART providing 100% software compatibility with the popular Texas Instruments 16550 device. It performs serial-to-parallel conversion on data originating from modems or other serial devices, and performs parallel-to-serial conversion on data from a CPU to these devices.
The H16550S can be run in either 16450- compatible character mode or in 16550- compatible FIFO mode, where an internal FIFO relieves the CPU of excessive software overhead.
Developed for easy reuse in FPGA or ASIC applications, the H16550S is available optimized for several technologies with competitive utilization and performance characteristics.
See representative implementation results (each in a new pop-up window):
Applications
The H16550S core can be utilized for many communication applications including:
- Serial or modem computer interface
- Serial interface within modems and other devices
Symbol Diagram

Block Diagram

Support
The core as delivered is warranted against defects for ninety days from purchase. Thirty days of phone and email technical support are included, starting with the first interaction. Additional maintenance and support options are available.
Verification
The core has been verified through extensive simulation and rigorous code coverage measurements.
Deliverables
The core is available in ASIC (synthesizable HDL) and FPGA (netlist) forms, and includes everything required for successful implementation:
- HDL RTL source code (ASICs) or post-synthesis EDIF netlist (FPGAs)
- Wrapper for pin compatible replacement
- Sophisticated HDL Testbench (self-checking)
- Simulation script, vectors, expected results, and comparison utility
- Synthesis script (ASICs) or place and route script (FPGAs)
- Comprehensive user documentation, including detailed specifications and a system integration guide

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