CGA_MIC_STACK_BIT12¶

Source: Verilog/DELILAH-CPU/CGA_MIC/circuit/CGA_MIC_STACK_BIT12.v

Where it sits (Simulation): ND120_TOP > ND120_CORE > ND3202D > CPU_15 > CPU_PROC_32 > CPU_PROC_CGA_33 > CGA > CGA_MIC > CGA_MIC_STACK > CGA_MIC_STACK_BIT12 - instance path: CORE.CPU_BOARD.CPU.PROC.CGA.DELILAH.MIC.MIC_STACK.Bit12

Used in: CGA_MIC_STACK (all tops)

Contains: D_FLIPFLOP_EN, NAND_GATE x4, NAND_GATE_3_INPUTS, OR_GATE x5, SR44_EN

Module hierarchy - All modules

CGA_MIC_STACK_BIT12 symbol

Schematic¶

Drawn from the Verilog: the yosys netlist of the Simulation (Verilator) build, instance CORE.CPU_BOARD.CPU.PROC.CGA.DELILAH.MIC.MIC_STACK.Bit12. Sub-modules are boxes (click the picture to open it full size; there every sub-module box links to its page, and every wire shows its Verilog name).

Description¶

ND120 CGA (CPU Gate Array / DELILAH) /CGA/MIC/STACK/BIT12 BIT12 Page 18 SHEET 1 of 1 Last reviewed: 10-NOV-2024 Ronny Hansen

Ports¶

Direction	Width	Name	Description
input	`1`	`sysclk`	FPGA system clock (P2: enable capture)
input	`1`	`MCLK_EN`	MCLK rise clock-enable pulse (FPGA_FF_MODE, else 0)
input	`1`	`MCLK_FALL_EN`	MCLK fall clock-enable pulse (FPGA_FF_MODE, else 0)
input	`1`	`LOAD`
input	`1`	`MCLK`	Main clock signal (from CGA_MIC.MCLK)
input	`1`	`S3`	SC[4:3] values - 00:HOLD, 01:POP, 10:LOAD, 11:PUSH (from CGA_MIC_STACK.SC3)
input	`1`	`S3N`
input	`1`	`S4NS3N`
input	`1`	`S4S3N`
input	`1`	`SCLKN`
input	`1`	`STIN`
output	`1`	`DEEP`
output	`1`	`STOUT`	Return Microcode Address (to CGA_MIC_STACK.RET_12_0[12])

Verilog source¶

Verilog/DELILAH-CPU/CGA_MIC/circuit/CGA_MIC_STACK_BIT12.v on GitHub.

Show the Verilog of CGA_MIC_STACK_BIT12 (219 lines)

/**************************************************************************
** ND120 CGA (CPU Gate Array / DELILAH)                                  **
** /CGA/MIC/STACK/BIT12                                                  **
** BIT12                                                                 **
**                                                                       **
** Page 18                                                               **
** SHEET 1 of 1                                                          **
**                                                                       **
** Last reviewed: 10-NOV-2024                                            **
** Ronny Hansen                                                          **
***************************************************************************/


module CGA_MIC_STACK_BIT12 (
    input sysclk,        //! FPGA system clock (P2: enable capture)
    input MCLK_EN,       //! MCLK rise clock-enable pulse (FPGA_FF_MODE, else 0)
    input MCLK_FALL_EN,  //! MCLK fall clock-enable pulse (FPGA_FF_MODE, else 0)

    input LOAD,
    input MCLK,          //! Main clock signal (from CGA_MIC.MCLK)
    input S3,            //! SC[4:3] values - 00:HOLD, 01:POP, 10:LOAD, 11:PUSH (from CGA_MIC_STACK.SC3)
    input S3N,
    input S4NS3N,
    input S4S3N,
    input SCLKN,
    input STIN,

    output DEEP,
    output STOUT         //! Return Microcode Address (to CGA_MIC_STACK.RET_12_0[12])
);

  /*******************************************************************************
   ** The wires are defined here                                                 **
   *******************************************************************************/
  wire s_gates4_out;
  wire s_gates7_out;
  wire s_s3_n;
  wire s_load;
  wire s_gates1_out;
  wire s_sti_n;
  wire s_gates9_out;
  wire s_mclk;
  wire s_sclk_n;
  wire s_sr44_qdn_out;
  wire s_s3;
  wire s_gates5_out;
  wire s_ff_sti_n_out;
  wire s_gates8_out;
  wire s_gates2_out;
  wire s_s4_s3_n;
  wire s_gates3_out;
  wire s_gates10_out;
  wire s_stout_out;
  wire s_deep_out;
  wire s_sr44_qbn_out;
  wire s_sr44_qcn_out;
  wire s_gates6_out;
  wire s_s4n_s3n;

  /*******************************************************************************
   ** The module functionality is described here                                 **
   *******************************************************************************/

  /*******************************************************************************
   ** Here all input connections are defined                                     **
   *******************************************************************************/
  assign s_load    = LOAD;
  assign s_mclk    = MCLK;
  assign s_s3      = S3;
  assign s_s3_n    = S3N;
  assign s_s4_s3_n = S4S3N;
  assign s_s4n_s3n = S4NS3N;
  assign s_sclk_n  = SCLKN;
  assign s_sti_n   = STIN;

  // P2 (docs/plan-fix-unconstrained-clocks.md): in FF mode the derived-
  // clock registers capture on posedge sysclk gated by the matching
  // enable pulse instead of clocking on the routed net.
`ifdef FPGA_FF_MODE
  localparam MCLK_CE = 1;
  localparam MCLK_FALL_CE = 1;
`else
  localparam MCLK_CE = 0;
  localparam MCLK_FALL_CE = 0;
`endif

  /*******************************************************************************
   ** Here all output connections are defined                                    **
   *******************************************************************************/
  assign DEEP      = s_deep_out;
  assign STOUT     = s_stout_out;

  /*******************************************************************************
   ** Here all normal components are defined                                     **
   *******************************************************************************/
  NAND_GATE #(
      .BubblesMask(2'b00)
  ) GATES_1 (
      .input1(s_ff_sti_n_out),
      .input2(s_s4_s3_n),
      .result(s_gates1_out)
  );

  NAND_GATE #(
      .BubblesMask(2'b00)
  ) GATES_2 (
      .input1(s_stout_out),
      .input2(s_s4n_s3n),
      .result(s_gates2_out)
  );

  OR_GATE #(
      .BubblesMask(2'b00)
  ) GATES_3 (
      .input1(s_sr44_qbn_out),
      .input2(s_s3_n),
      .result(s_gates3_out)
  );

  OR_GATE #(
      .BubblesMask(2'b00)
  ) GATES_4 (
      .input1(s_s3),
      .input2(s_sr44_qbn_out),
      .result(s_gates4_out)
  );

  OR_GATE #(
      .BubblesMask(2'b00)
  ) GATES_5 (
      .input1(s_s3_n),
      .input2(s_sr44_qcn_out),
      .result(s_gates5_out)
  );

  OR_GATE #(
      .BubblesMask(2'b00)
  ) GATES_6 (
      .input1(s_s3),
      .input2(s_sr44_qcn_out),
      .result(s_gates6_out)
  );

  OR_GATE #(
      .BubblesMask(2'b00)
  ) GATES_7 (
      .input1(s_s3_n),
      .input2(s_sr44_qdn_out),
      .result(s_gates7_out)
  );

  NAND_GATE_3_INPUTS #(
      .BubblesMask(3'b000)
  ) GATES_8 (
      .input1(s_gates3_out),
      .input2(s_gates1_out),
      .input3(s_gates2_out),
      .result(s_gates8_out)
  );

  NAND_GATE #(
      .BubblesMask(2'b00)
  ) GATES_9 (
      .input1(s_gates4_out),
      .input2(s_gates5_out),
      .result(s_gates9_out)
  );

  NAND_GATE #(
      .BubblesMask(2'b00)
  ) GATES_10 (
      .input1(s_gates6_out),
      .input2(s_gates7_out),
      .result(s_gates10_out)
  );

  // MCLK domain: s_mclk = MCLK, clocked on posedge MCLK
  D_FLIPFLOP_EN #(
      .USE_ENABLE(MCLK_CE)
  ) MEMORY_11 (
      .sysclk(sysclk),
      .EN(MCLK_EN),
      .clock(s_mclk),
      .d(s_sti_n),
      .preset(1'b0),
      .q(s_ff_sti_n_out),
      .qBar(),
      .reset(1'b0),
      .tick(1'b1)
  );


  /*******************************************************************************
   ** Here all sub-circuits are defined                                          **
   *******************************************************************************/

  // MCLK_FALL domain: s_sclk_n = SCLKN = ~MCLK, posedge ~MCLK = MCLK falling edge
  SR44_EN #(.USE_ENABLE(MCLK_FALL_CE)) SR44_2 (
      .sysclk(sysclk),
      .EN(MCLK_FALL_EN),
      .CP(s_sclk_n),

      .A  (s_gates8_out),
      .B  (s_gates9_out),
      .C  (s_gates10_out),
      .D  (s_deep_out),
      .L  (s_load),
      .QA (s_stout_out),
      .QAN(),
      .QB (),
      .QBN(s_sr44_qbn_out),
      .QC (),
      .QCN(s_sr44_qcn_out),
      .QD (s_deep_out),
      .QDN(s_sr44_qdn_out),
      .SI (s_ff_sti_n_out)
  );

endmodule