D16450 Configurable UART ver 2.07 OVERVIEW The D16450 is a soft Core of a Universal Asynchronous Receiver/Transmitter (UART) functionally identical to the TL16C450. D16450 performs serial-to-parallel conversion on data characters received from a peripheral device or a MODEM, and parallel-to-serial conversion on data characters received from the CPU. The CPU can read the complete status of the UART at any time during the functional operation. Status information reported includes the type and condition of the transfer operations being performed by the UART, as well as any error conditions (parity, overrun, framing, or break interrupt). D16450 includes a programmable baud rate generator that is capable of dividing the timing reference clock input by divisors of 1 to (216-1), and producing a 16 × clock for driving the internal transmitter logic. Provisions are also included to use this 16 × clock to drive the receiver logic. The D16450 has complete MODEM control capability, and a processor-interrupt system. Interrupts can be programmed to the user's requirements, minimizing the computing required to handle the communications link. The separate BAUD CLK line allows to set an exact transmission speed, while the UART internal logic is clocked with the CPU frequency as for standalone implementation, where several UARTs are required to be implemented inside a single chip, and driven by some off-chip devices. Thanks to universal interface D16450 core implementation and verification are very simply, by eliminating a number of clock trees in complete system. KEY FEATURES ● Software compatible with 16450 UART ● Configuration capability ● Separate configurable BAUD clock line ● Majority Voting Logic ● Adds or deletes standard asynchronous communication bits (start, stop, and parity) to or from the serial data ● In UART mode receiver and transmitter are double buffered to eliminate a need for precise synchronization between the CPU and serial data ● Independently controlled transmit, receive, line status, and data set interrupts ● False start bit detection ● 16 bit programmable baud generator ● MODEM control functions (CTS, RTS, DSR, DTR, RI, and DCD) The core is perfect for applications, where the UART Core and microcontroller are clocked by the same clock signal and are implemented inside the same ASIC or FPGA chip, as well All trademarks mentioned in this document are trademarks of their respective owners. http://www.DigitalCoreDesign.com http://www.dcd.pl Copyright 1999-2007 DCD – Digital Core Design. All Rights Reserved. ● Fully programmable characteristics: serial-interface Source code: VHDL Source Code or/and VERILOG Source Code or/and Encrypted, or plain text EDIF netlist VHDL & VERILOG test bench environment ◊ Active-HDL automatic simulation macros ◊ ModelSim automatic simulation macros ◊ Tests with reference responses Technical documentation ◊ Installation notes ◊ HDL core specification ◊ Datasheet Synthesis scripts Example application Technical support ◊ IP Core implementation support ◊ 3 months maintenance ♦ ○ 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 Complete status reporting capabilities ● Line break generation and detection. Internal diagnostic capabilities: ○ Loop-back controls for communications link fault isolation ○ Break, parity, overrun, framing error simulation HDL ◊ ◊ ◊ ♦ ● independent DELIVERABLES Source ♦ ♦ ♦ ♦ ● Technology Code ● Full prioritized interrupt system controls ● ● Fully synthesizable static design with no internal tri-state buffers ● ● Delivery the IP Core updates, minor and major versions changes Delivery the documentation updates Phone & email support APPLICATIONS ● Serial Data communications applications ● Modem interface LICENSING Comprehensible and clearly defined licensing methods without royalty fees make using of IP Core easy and simply. Single Design license allows use IP Core in single FPGA bitstream and ASIC implementation. Unlimited Designs, One Year licenses allow use IP Core in unlimited number of FPGA bitstreams and ASIC implementations. In all cases number of IP Core instantiations within a design, and number of manufactured chips are unlimited. There is no time restriction except One Year license where time of use is limited to 12 months. ● Single Design license for ○ VHDL, Verilog source code called HDL Source ○ Encrypted, or plain text EDIF called Netlist ● One Year license for ○ ● ● All trademarks mentioned in this document are trademarks of their respective owners. Encrypted Netlist only Unlimited Designs license for ○ HDL Source ○ Netlist Upgrade from http://www.DigitalCoreDesign.com http://www.dcd.pl Copyright 1999-2007 DCD – Digital Core Design. All Rights Reserved. ○ HDL Source to Netlist ○ Single Design to Unlimited Designs SYMBOL rst clk rclk baudclk CONFIGURATION The following parameters of the D16450 core can be easy adjusted to requirements of dedicated application and technology. Configuration of the core can be prepared by effortless changing appropriate constants in package file. There is no need to change any parts of the code. • Baud generator - enable disable • External RCLK source - enable disable • External BAUDCLK source - enable disable • Modem Control logic - enable disable • SCR Register - enable disable DESIGN FEATURES The functionality of the D16450 core was based on the Texas Instruments TL16C450. The following characteristics differentiate the D16450 from Texas Instruments devices: ● The bi-directional data bus has been split into two separate buses: datai(7:0), datao(7:0) ● Signals rd2 and wr2, xin, and xout have been removed from interface ● Signal ADS and address latch have been removed The DLL, DLM and THR registers are reset to all zeros ● ● TEMT and THRE bits of Line Status Register, are reset during the second clock rising edge following a THR write ● RCLK clock is replaced by global clock CLK, internally divided by BAUD factor. ● Asynchronous microcontroller interface is replaced by equivalent Universal interface ● All latches implemented in original 16450 devices are replaced by equivalent flip-flop registers, with the same functionality All trademarks mentioned in this document are trademarks of their respective owners. baudout intr datai(7:0) address(2:0) wr rd cs datao(7:0) ddis D16450 so si cts dsr dcd ri rts dtr out1 out2 baudclken rclken PINS DESCRIPTION PIN TYPE DESCRIPTION rst input Global reset clk input Global clock datai[7:0] input Parallel data input addr[2:0] input Address bus cs input Chip select input wr input Write input rd input Read input rclk input Receiver clock baudclk input Baud generator clock si input Serial data input cts input Clear to send input dsr input Data set ready input dcd input Data carrier detect input ri input Ring indicator input baudclken input Baud generator clock enable rclken input Receiver clock enable baudout output Baud generator output datao[7:0] output Parallel data output so output Serial data output ddis output Driver disable output rts output Request to send output dtr output Data terminal ready output out1 output Output 1 out2 output Output 2 intr output Interrupt request output Note: When enabled RCLK and BAUDCLK pins frequency should be at least two times lower than CLK, 2*fRCLK< fCLK http://www.DigitalCoreDesign.com http://www.dcd.pl Copyright 1999-2007 DCD – Digital Core Design. All Rights Reserved. Modem Control Logic controls the interface with the MODEM or data set (or a peripheral device emulating a MODEM). APPLICATION addr CPU ale datao(7:0) datai(7:0) we rd cs int addr latch addr(2:0) clk rst D16450 baudclk rclk datai(7:0) datao(7:0) wr rd cs intr out1 out2 so si rts dtr dsr dcd cts ri Interrupt Controller - D16450 consists fully prioritized interrupt system controller. It controls interrupt requests to the CPU and interrupt priority. Interrupt controller contains Interrupt Enable (IER) and Interrupt Identification (IIR) registers. EIA Drivers baudclken rclken addr(2:0) datai(7:0) datao(7:0) rd wr cs Data Bus Buffer ddis Typical D16450 and processor connection is shown in figure above. Receiver Control & Shift Register rclk rclken si Transmitter Control & Shift Register so Interrupt Controller BLOCK DIAGRAM Data Bus Buffer - The data Bus Buffer accepts inputs from the system bus and generates control signals for the other D14750 functional blocks. Address bus ADDR(2:0) selects one of the register to be read from/written into. Both RD and WE signals are active low, and are qualified by CS; RD and WE are ignored unless the D16450 has been selected by holding CS low. Baud Generator - The D16450 contains a programmable 16 bit baud generator that divides clock input by a divisor in the range between 1 and (216–1). The output frequency of the baud generator is 16× the baud rate. The formula for the divisor is: frequency divisor = baudrate * 16 Two 8-bit registers, called divisor latches DLL and DLM, store the divisor in a 16-bit binary format. These divisor latches must be loaded during initialization of the D16450 in order to ensure desired operation of the baud generator. When either of the divisor latches is loaded, a 16-bit baud counter is also loaded on the CLK rising edge following the write to DLL or DLM to prevent long counts on initial load. All trademarks mentioned in this document are trademarks of their respective owners. baudclk baudclken baudout Baud Generator Modem control logic clk rst rts cts dtr dsr dcd ri out1 out2 Receiver Control - Receiving starts when the falling edge on Serial Input (SI) during IDLE State is detected. After starting the SI input is sampled every 16 internal baud cycles as it is shown in figure below. When the logic 1 state is detected during START bit it means that the False Start bit was detected and receiver back to the IDLE state. Transmitter Control module controls transmission of written to THR (Transmitter Holding register) character via serial output SO. The new transmission starts on the next overflow signal of internal baud generator, after writing to THR register or Transmitter FIFO. Transmission control contains THR register and transmitter shift register. http://www.DigitalCoreDesign.com http://www.dcd.pl Copyright 1999-2007 DCD – Digital Core Design. All Rights Reserved. PERFORMANCE The following table gives a survey about the Core area and performance in the ALTERA® devices after Place & Route: Speed Logic Cells Fmax grade CYCLONE -6 301 190 MHz CYCLONE 2 -6 303 222 MHz STRATIX -5 301 213 MHz STRATIX 2 -3 248 283 MHz STRATIXGX -5 301 212 MHz MERCURY -5 350 222 MHz EXCALIBUR -1 340 137 MHz APEX II -7 340 145 MHz APEX20KC -7 340 143 MHz APEX20KE -1 340 122 MHz APEX20K -1 340 83 MHz ACEX1K -1 363 99 MHz FLEX10KE -1 363 98 MHz Core performance in ALTERA® devices Device D16X50 UARTS FAMILY OVERVIEW -* -* -* -* -* -* -* -* -* -* - *-Optional D16X50 family of Configurable UARTs with FIFO IP Cores All trademarks mentioned in this document are trademarks of their respective owners. 1284 Parallel Port Break generation and detection Prioritized interrupt system Internal diagnostic capabilities Complete status reporting False START Bit detection - MODEM Control Separate BAUD Clock line - IRDA Port 2* 16 2* 64 4* 16 4* 64 8* 64 Majority voting logic FIFO Size (Bytes) FIFO Mode of operation - RTS/CTS Flow Control 1 1 1 2 2 4 Software Flow Control D16450 D16550 D16750 D16552 D16752 D16754 UART Mode Design UARTS number The family of DCD D16X50 UART IP Cores combine a high–performance, low cost, and small compact size, offering the best price/performance ratio in the IP Market. The DCD’s Cores are dedicated for use in cost-sensitive consumer products, computer peripherals, office automation, automotive control systems, security and telecommunication applications. The D16X50 IP Cores are written in pure VHDL/VERILOG HDL languages which make them technologically independent. All of the D16X50 IP Cores can be fully customized according to customer needs. http://www.DigitalCoreDesign.com http://www.dcd.pl Copyright 1999-2007 DCD – Digital Core Design. All Rights Reserved. CONTACTS For any modification or special request please contact to Digital Core Design or local distributors. Headquarters: Wroclawska 94 41-902 Bytom, POLAND [email protected] e-mail: [email protected] tel. : +48 32 282 82 66 fax : +48 32 282 74 37 Distributors: ttp://www.dcd.pl/apartn.php Please check hhttp://www.dcd.pl/apartn.php All trademarks mentioned in this document are trademarks of their respective owners. http://www.DigitalCoreDesign.com http://www.dcd.pl Copyright 1999-2007 DCD – Digital Core Design. All Rights Reserved.