C2910A

C2910A Microprogram Controller Megafunction General Description The C2910A microprogram controller megafunction is an address sequencer that controls the sequence of execution for the microinstructions stored in microprogram memory. The megafunction can sequentially access the microinstructions, and it provides conditional branching to any microinstructions within the 4,096microword range. In addition, a nine-deep LIFO stack provides a microsubroutine return linkage and looping capability. Features • • • • • • • • 12-bit data width that addresses up to 4,096 words Internal Loop Counter - Pre-settable 12-bit down-counter for repeating instructions and counting loop interactions Four Address Sources - Microprogram Address may be selected from microprogram counter, branch address bus, 9-level push/pop stack, or internal holding register 16 powerful microinstructions Output Enable Controls for Three Branch Address Sources Positive-edge-triggered registers Also available in VHDL or Verilog Functionality based on the Advanced Micro Devices AM2910A Symbol CP IR[3:0] DATA[11:0] CCN CCENN RLDN CI OEN Y[11:0] FULLN PLN MAPN VECTN CAST, Inc. March 2004 Page 1 CAST C2910A Megafunction Datasheet Applications The C2910A megafunction is used in high-speed bit-slice designs. Pin Description Name Type Polarity Description / Bus Size CP IR DATA CCN CCENN RLDN CI OEN Y FULLN PLN MAPN VECTN In In In In In In In In Out Out Out Out Out Rising 4 12 Low Low Low Low 12 Low Low Low Low Clock Instruction Direct Data Condition Code Condition Code Enable Register Load Enable Carry-In Output Enable Microprogram Address Full Flag Pipeline Address Enable Map Address Enable Vector Address Enable Block Diagram DATA (11:0) CP RLDN Register/Counter Stack 9 x 12 Zero Detector FULLN Microprogram Counter-Register Multiplexer CCN CCENN IR (3:0) Instruction Decoder Incrementer CI PLN MAPN VECTN Y (11:0) OEN CAST, Inc. Page 2 CAST C2910A Megafunction Datasheet Functional Description The C2910A megafunction is partitioned into modules as shown above and described below. Multiplexer The four-input multiplexer is used to select either the register/counter, direct input, microprogram counter, or stack as the source of the next microinstruction address. Register Counter This block consists of 12 D-type, edge-triggered flip-flops, with a common enable. When its load control, RLDN is low, new data is loaded on a positive clock transition. The output of the register/counter is available to the multiplexer as a source for the next microinstruction address. The direct input furnishes a source of data for loading the register/counter. Microcontroller Counter/Register (µPC) This block consists of a 12-bit incrementer followed by a 12-bit register. The µPC can be used in either of two ways: When the carry-in to the incrementer is high, the microprogram register is loaded on the next clock cycle with the current Y output word plus one (Y + 1 → µPC). Sequential microinstructions are thus executed. When the carry-in is low, the incrementer passes the Y output word unmodified so that µPC is reloaded with the same Y word on the next clock cycle (Y → µPC). The same microinstruction is thus executed any number of times. Stack This 9-word by 12-bit stack is used to provide return address linkage when executing microsubroutines or loops. The stack contains a built-in stack pointer which always points to the last word written. This allows stack reference operations (looping) to be performed without a pop. Instruction Decoder This block decodes the incoming instruction and generates the appropriate control signals for all the other blocks. The instruction decoder block also generates the outputs PLN, MAPN, and VECTN Verification Methods The C2910A megafunction’s functionality was verified by means of a proprietary hardware modeler. The same stimulus was applied to a hardware model which contained the original AMD 2910A chip, and the results compared with the megafunction’s simulation outputs. Device Utilization & Performance Supported Family Cyclone Stratix Stratix-II Device Tested EP1C20-6 EP1S20-5 EP2S60-3 LEs 294 294 232 Utilization Memory Memory bits 0 0 0 0 0 0 Performance Fmax 139 MHz 138 MHz 148 MHz CAST, Inc. Page 3 CAST C2910A Megafunction Datasheet Deliverables Encrypted Licenses • • • • • • • • • • • • • • Post-synthesis EDIF netlist Place & route scripts Assignment & Configuration Symbol file Include file Testbench (self-checking) Vectors for testing the core Documentation HDL Source Licenses VHDL or Verilog HDL source code Testbench (self-checking) Vectors for testing the core Simulation script Synthesis script Documentation Megafunction Modifications The C2910A megafunction can be customized to include: • • Different data width Different stack depth Please contact CAST for any required modifications Contact Information CAST, Inc. 11 Stonewall Court Woodcliff Lake, New Jersey 07677 USA Phone: +1 201-391-8300 Fax: +1 201-391-8694 E-Mail: info@cast-inc.com URL: www.cast-inc.com Copyright © CAST, Inc. 2004, All Rights Reserved. Contents subject to change without notice CAST, Inc. Page 4