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-rw-r--r--rtl/src/verilog/cdc_bus_pulse.v216
-rw-r--r--rtl/src/verilog/core_selector.v220
-rw-r--r--rtl/src/verilog/eim_arbiter.v486
-rw-r--r--rtl/src/verilog/eim_da_phy.v72
-rw-r--r--rtl/src/verilog/novena_baseline_top.v208
-rw-r--r--rtl/src/verilog/novena_clkmgr.v162
6 files changed, 682 insertions, 682 deletions
diff --git a/rtl/src/verilog/cdc_bus_pulse.v b/rtl/src/verilog/cdc_bus_pulse.v
index 104bfa5..631506c 100644
--- a/rtl/src/verilog/cdc_bus_pulse.v
+++ b/rtl/src/verilog/cdc_bus_pulse.v
@@ -1,114 +1,114 @@
-`timescale 1ns / 1ps
-
-module cdc_bus_pulse
- (
- src_clk, src_din, src_req,
- dst_clk, dst_dout, dst_pulse
- );
-
- /* This module is based on design suggested on page 27 of an article titled
- "Clock Domain Crossing (CDC) Design & Verification Techniques Using SystemVerilog"
- by Clifford E. Cummings (Sunburst Design, Inc.)
- */
-
- //
- // Parameters
- //
- parameter DATA_WIDTH = 32; // width of data bus
-
-
- //
- // Ports
- //
- input wire src_clk; // source domain clock
- input wire [DATA_WIDTH-1:0] src_din; // data from source clock domain
- input wire src_req; // start transfer pulse from source clock domain
-
- input wire dst_clk; // destination domain clock
- output wire [DATA_WIDTH-1:0] dst_dout; // data to destination clock domain
- output wire dst_pulse; // transfer done pulse to destination clock domain
-
-
- //
- // Source Side Registers
- //
- reg src_ff = 1'b0; // transfer request flag
- reg [DATA_WIDTH-1:0] src_latch = {DATA_WIDTH{1'bX}}; // source data buffer
-
-
- //
- // Source Request Handler
- //
- always @(posedge src_clk)
- //
- if (src_req) begin // transfer request pulse?
- src_ff <= ~src_ff; // toggle transfer request flag...
- src_latch <= src_din; // ... and capture data in source buffer
- end
-
-
- //
- // Source -> Destination Flag Sync Logic
- //
-
- /* ISE may decide to infer SRL here, so we explicitly instantiate slice registers. */
-
- wire flag_sync_first; // first FF output
- wire flag_sync_second; // second FF output
- wire flag_sync_third; // third FF output
- wire flag_sync_pulse; // flag toggle detector output
-
- FDCE ff_sync_first
- (
- .C (dst_clk),
+`timescale 1ns / 1ps
+
+module cdc_bus_pulse
+ (
+ src_clk, src_din, src_req,
+ dst_clk, dst_dout, dst_pulse
+ );
+
+ /* This module is based on design suggested on page 27 of an article titled
+ "Clock Domain Crossing (CDC) Design & Verification Techniques Using SystemVerilog"
+ by Clifford E. Cummings (Sunburst Design, Inc.)
+ */
+
+ //
+ // Parameters
+ //
+ parameter DATA_WIDTH = 32; // width of data bus
+
+
+ //
+ // Ports
+ //
+ input wire src_clk; // source domain clock
+ input wire [DATA_WIDTH-1:0] src_din; // data from source clock domain
+ input wire src_req; // start transfer pulse from source clock domain
+
+ input wire dst_clk; // destination domain clock
+ output wire [DATA_WIDTH-1:0] dst_dout; // data to destination clock domain
+ output wire dst_pulse; // transfer done pulse to destination clock domain
+
+
+ //
+ // Source Side Registers
+ //
+ reg src_ff = 1'b0; // transfer request flag
+ reg [DATA_WIDTH-1:0] src_latch = {DATA_WIDTH{1'bX}}; // source data buffer
+
+
+ //
+ // Source Request Handler
+ //
+ always @(posedge src_clk)
+ //
+ if (src_req) begin // transfer request pulse?
+ src_ff <= ~src_ff; // toggle transfer request flag...
+ src_latch <= src_din; // ... and capture data in source buffer
+ end
+
+
+ //
+ // Source -> Destination Flag Sync Logic
+ //
+
+ /* ISE may decide to infer SRL here, so we explicitly instantiate slice registers. */
+
+ wire flag_sync_first; // first FF output
+ wire flag_sync_second; // second FF output
+ wire flag_sync_third; // third FF output
+ wire flag_sync_pulse; // flag toggle detector output
+
+ FDCE ff_sync_first
+ (
+ .C (dst_clk),
.D (src_ff), // capture flag from another clock domain
- .Q (flag_sync_first), // metastability can occur here
- .CLR (1'b0),
+ .Q (flag_sync_first), // metastability can occur here
+ .CLR (1'b0),
.CE (1'b1)
- );
- FDCE ff_sync_second
- (
- .C (dst_clk),
+ );
+ FDCE ff_sync_second
+ (
+ .C (dst_clk),
.D (flag_sync_first), // synchronize captured flag to remove metastability
- .Q (flag_sync_second), // and pass it to another flip-flop
- .CLR (1'b0),
+ .Q (flag_sync_second), // and pass it to another flip-flop
+ .CLR (1'b0),
.CE (1'b1)
- );
- FDCE ff_sync_third
- (
- .C (dst_clk),
+ );
+ FDCE ff_sync_third
+ (
+ .C (dst_clk),
.D (flag_sync_second), // delay synchronized flag in another flip-flip, because we need
- .Q (flag_sync_third), // two synchronized flag values (current and delayed) to detect its change
- .CLR (1'b0),
+ .Q (flag_sync_third), // two synchronized flag values (current and delayed) to detect its change
+ .CLR (1'b0),
.CE (1'b1)
- );
-
- // when delayed flag value differs from its current value, it was changed
- // by the source side, so there must have been a transfer request
- assign flag_sync_pulse = flag_sync_second ^ flag_sync_third;
-
-
- //
- // Destination Side Registers
- //
- reg dst_pulse_reg = 1'b0; // transfer done flag
- reg [DATA_WIDTH-1:0] dst_latch = {DATA_WIDTH{1'bX}}; // destination data buffer
-
- assign dst_pulse = dst_pulse_reg;
- assign dst_dout = dst_latch;
-
- //
- // Destination Request Handler
- //
- always @(posedge dst_clk) begin
- //
- dst_pulse_reg <= flag_sync_pulse; // generate pulse if flag change was detected
- //
- if (flag_sync_pulse) dst_latch <= src_latch; // by the time destination side receives synchronized
- // // flag value, data should be stable, we can safely
- // // capture and store it in the destination buffer
- //
- end
-
-
-endmodule
+ );
+
+ // when delayed flag value differs from its current value, it was changed
+ // by the source side, so there must have been a transfer request
+ assign flag_sync_pulse = flag_sync_second ^ flag_sync_third;
+
+
+ //
+ // Destination Side Registers
+ //
+ reg dst_pulse_reg = 1'b0; // transfer done flag
+ reg [DATA_WIDTH-1:0] dst_latch = {DATA_WIDTH{1'bX}}; // destination data buffer
+
+ assign dst_pulse = dst_pulse_reg;
+ assign dst_dout = dst_latch;
+
+ //
+ // Destination Request Handler
+ //
+ always @(posedge dst_clk) begin
+ //
+ dst_pulse_reg <= flag_sync_pulse; // generate pulse if flag change was detected
+ //
+ if (flag_sync_pulse) dst_latch <= src_latch; // by the time destination side receives synchronized
+ // // flag value, data should be stable, we can safely
+ // // capture and store it in the destination buffer
+ //
+ end
+
+
+endmodule
diff --git a/rtl/src/verilog/core_selector.v b/rtl/src/verilog/core_selector.v
index 2db2a05..eb6551a 100644
--- a/rtl/src/verilog/core_selector.v
+++ b/rtl/src/verilog/core_selector.v
@@ -1,112 +1,112 @@
-`timescale 1ns / 1ps
-
-module core_selector
- (
- sys_clk, sys_rst,
+`timescale 1ns / 1ps
+
+module core_selector
+ (
+ sys_clk, sys_rst,
sys_eim_addr, sys_eim_wr, sys_eim_rd,
- sys_eim_dout, sys_eim_din
- );
-
- //
- // Ports
- //
- input wire sys_clk;
- input wire sys_rst;
-
- input wire [13: 0] sys_eim_addr;
- input wire sys_eim_wr;
+ sys_eim_dout, sys_eim_din
+ );
+
+ //
+ // Ports
+ //
+ input wire sys_clk;
+ input wire sys_rst;
+
+ input wire [13: 0] sys_eim_addr;
+ input wire sys_eim_wr;
input wire sys_eim_rd;
- input wire [31: 0] sys_eim_dout;
- output wire [31: 0] sys_eim_din;
-
-
- //
- // Internal Registers
- //
- reg [31: 0] reg_x = {32{1'b0}};
- reg [31: 0] reg_y = {32{1'b0}};
- reg [15: 0] reg_ctl = {16{1'b0}};
- reg [31: 0] sys_eim_din_reg = {32{1'b0}};
-
-
- //
- // Parameters
- //
- localparam ADDER_BASE_ADDR = 12'h321; // upper 12 bits of address
- localparam ADDER_OFFSET_REG_X = 2'd0; // X
- localparam ADDER_OFFSET_REG_Y = 2'd1; // Y
- localparam ADDER_OFFSET_REG_Z = 2'd2; // Z
- localparam ADDER_OFFSET_REG_SC = 2'd3; // {STATUS, CONTROL}
-
-
- /* This flag detects whether adder core is being addressed. */
- wire eim_access_adder = (sys_eim_addr[13:2] == ADDER_BASE_ADDR) ? 1'b1 : 1'b0;
-
- /* These flags detect whether write or read access is requested. */
- wire eim_access_write = sys_eim_wr & eim_access_adder;
- wire eim_access_read = sys_eim_rd & eim_access_adder;
-
-
- //
- // Write Request Handler
- //
- always @(posedge sys_clk)
- //
- if (sys_rst) begin
- reg_x <= {32{1'b0}};
- reg_y <= {32{1'b0}};
- reg_ctl <= {16{1'b0}};
- end else if (eim_access_write) begin
- //
- case (sys_eim_addr[1:0])
- ADDER_OFFSET_REG_X: reg_x <= sys_eim_dout;
- ADDER_OFFSET_REG_Y: reg_y <= sys_eim_dout;
- ADDER_OFFSET_REG_SC: reg_ctl <= sys_eim_dout[15: 0];
- endcase
- //
- end
-
-
- //
- // Read Request Handler
- //
- wire [31: 0] reg_z;
- wire [15: 0] reg_sts;
-
- always @(posedge sys_clk)
- //
- if (sys_rst) sys_eim_din_reg <= {32{1'b0}};
- //
- else if (eim_access_read) begin
- //
- case (sys_eim_addr[1:0])
- ADDER_OFFSET_REG_X: sys_eim_din_reg <= reg_x;
- ADDER_OFFSET_REG_Y: sys_eim_din_reg <= reg_y;
- ADDER_OFFSET_REG_Z: sys_eim_din_reg <= reg_z;
- ADDER_OFFSET_REG_SC: sys_eim_din_reg <= {reg_sts, reg_ctl};
- endcase
- //
- end
-
- assign sys_eim_din = sys_eim_din_reg;
-
-
- //
- // Demo Adder Core
- //
- demo_adder adder_core
- (
- .clk (sys_clk),
- .rst (sys_rst),
-
- .x (reg_x),
- .y (reg_y),
- .z (reg_z),
-
- .ctl (reg_ctl),
- .sts (reg_sts)
- );
-
-
-
-endmodule
+ input wire [31: 0] sys_eim_dout;
+ output wire [31: 0] sys_eim_din;
+
+
+ //
+ // Internal Registers
+ //
+ reg [31: 0] reg_x = {32{1'b0}};
+ reg [31: 0] reg_y = {32{1'b0}};
+ reg [15: 0] reg_ctl = {16{1'b0}};
+ reg [31: 0] sys_eim_din_reg = {32{1'b0}};
+
+
+ //
+ // Parameters
+ //
+ localparam ADDER_BASE_ADDR = 12'h321; // upper 12 bits of address
+ localparam ADDER_OFFSET_REG_X = 2'd0; // X
+ localparam ADDER_OFFSET_REG_Y = 2'd1; // Y
+ localparam ADDER_OFFSET_REG_Z = 2'd2; // Z
+ localparam ADDER_OFFSET_REG_SC = 2'd3; // {STATUS, CONTROL}
+
+
+ /* This flag detects whether adder core is being addressed. */
+ wire eim_access_adder = (sys_eim_addr[13:2] == ADDER_BASE_ADDR) ? 1'b1 : 1'b0;
+
+ /* These flags detect whether write or read access is requested. */
+ wire eim_access_write = sys_eim_wr & eim_access_adder;
+ wire eim_access_read = sys_eim_rd & eim_access_adder;
+
+
+ //
+ // Write Request Handler
+ //
+ always @(posedge sys_clk)
+ //
+ if (sys_rst) begin
+ reg_x <= {32{1'b0}};
+ reg_y <= {32{1'b0}};
+ reg_ctl <= {16{1'b0}};
+ end else if (eim_access_write) begin
+ //
+ case (sys_eim_addr[1:0])
+ ADDER_OFFSET_REG_X: reg_x <= sys_eim_dout;
+ ADDER_OFFSET_REG_Y: reg_y <= sys_eim_dout;
+ ADDER_OFFSET_REG_SC: reg_ctl <= sys_eim_dout[15: 0];
+ endcase
+ //
+ end
+
+
+ //
+ // Read Request Handler
+ //
+ wire [31: 0] reg_z;
+ wire [15: 0] reg_sts;
+
+ always @(posedge sys_clk)
+ //
+ if (sys_rst) sys_eim_din_reg <= {32{1'b0}};
+ //
+ else if (eim_access_read) begin
+ //
+ case (sys_eim_addr[1:0])
+ ADDER_OFFSET_REG_X: sys_eim_din_reg <= reg_x;
+ ADDER_OFFSET_REG_Y: sys_eim_din_reg <= reg_y;
+ ADDER_OFFSET_REG_Z: sys_eim_din_reg <= reg_z;
+ ADDER_OFFSET_REG_SC: sys_eim_din_reg <= {reg_sts, reg_ctl};
+ endcase
+ //
+ end
+
+ assign sys_eim_din = sys_eim_din_reg;
+
+
+ //
+ // Demo Adder Core
+ //
+ demo_adder adder_core
+ (
+ .clk (sys_clk),
+ .rst (sys_rst),
+
+ .x (reg_x),
+ .y (reg_y),
+ .z (reg_z),
+
+ .ctl (reg_ctl),
+ .sts (reg_sts)
+ );
+
+
+
+endmodule
diff --git a/rtl/src/verilog/eim_arbiter.v b/rtl/src/verilog/eim_arbiter.v
index 247ff69..1e39629 100644
--- a/rtl/src/verilog/eim_arbiter.v
+++ b/rtl/src/verilog/eim_arbiter.v
@@ -1,247 +1,247 @@
-`timescale 1ns / 1ps
-
-module eim_arbiter
- (
+`timescale 1ns / 1ps
+
+module eim_arbiter
+ (
eim_bclk, eim_cs0_n, eim_da,
eim_lba_n, eim_wr_n,
- eim_oe_n, eim_wait_n,
-
- sys_clk,
- sys_addr,
- sys_wren, sys_data_out,
- sys_rden, sys_data_in
- );
-
-
- //
- // Ports
- //
- input wire eim_bclk; // | eim bus
- input wire eim_cs0_n; // |
+ eim_oe_n, eim_wait_n,
+
+ sys_clk,
+ sys_addr,
+ sys_wren, sys_data_out,
+ sys_rden, sys_data_in
+ );
+
+
+ //
+ // Ports
+ //
+ input wire eim_bclk; // | eim bus
+ input wire eim_cs0_n; // |
inout wire [15: 0] eim_da; // |
- input wire eim_lba_n; // |
+ input wire eim_lba_n; // |
input wire eim_wr_n; // |
- input wire eim_oe_n; // |
- output wire eim_wait_n; // |
-
- input wire sys_clk; // system clock
-
- output wire [13: 0] sys_addr; // | user bus
- output wire sys_wren; // |
- output wire [31: 0] sys_data_out; // |
- output wire sys_rden; // |
- input wire [31: 0] sys_data_in; // |
-
-
- //
- // Data/Address PHY
- //
-
- /* PHY is needed to control bi-directional address/data bus. */
-
- wire [15: 0] da_ro; // value read from pins
- reg [15: 0] da_di; // value drives onto pins
-
- eim_da_phy da_phy
- (
- .buf_io (eim_da), // <-- connect directly top-level port
- .buf_di (da_di),
- .buf_ro (da_ro),
- .buf_t (eim_oe_n) // <-- driven by EIM directly
- );
-
-
- //
- // FSM
- //
- localparam EIM_FSM_STATE_INIT = 5'b0_0_000; // arbiter is idle
-
- localparam EIM_FSM_STATE_WRITE_START = 5'b1_1_000; // got address to write at
- localparam EIM_FSM_STATE_WRITE_LSB = 5'b1_1_001; // got lower 16 bits of data to write
- localparam EIM_FSM_STATE_WRITE_MSB = 5'b1_1_010; // got upper 16 bits of data to write
- localparam EIM_FSM_STATE_WRITE_WAIT = 5'b1_1_100; // request to user-side logic sent
- localparam EIM_FSM_STATE_WRITE_DONE = 5'b1_1_111; // user-side logic acknowledged transaction
-
- localparam EIM_FSM_STATE_READ_START = 5'b1_0_000; // got address to read from
- localparam EIM_FSM_STATE_READ_WAIT = 5'b1_0_100; // request to user-side logic sent
- localparam EIM_FSM_STATE_READ_READY = 5'b1_0_011; // got acknowledge from user logic
- localparam EIM_FSM_STATE_READ_LSB = 5'b1_0_001; // returned lower 16 bits to master
- localparam EIM_FSM_STATE_READ_MSB = 5'b1_0_010; // returned upper 16 bits to master
- localparam EIM_FSM_STATE_READ_DONE = 5'b1_0_111; // transaction complete
-
- reg [ 4: 0] eim_fsm_state = EIM_FSM_STATE_INIT; // fsm state
- reg [13: 0] eim_addr_latch = {14{1'bX}}; // transaction address
- reg [15: 0] eim_write_lsb_latch = {16{1'bX}}; // lower 16 bits of data to write
-
- /* These flags are used to wake up from INIT state. */
- wire eim_write_start_flag = (eim_lba_n == 1'b0) && (eim_wr_n == 1'b0) && (da_ro[1:0] == 2'b00);
- wire eim_read_start_flag = (eim_lba_n == 1'b0) && (eim_wr_n == 1'b1) && (da_ro[1:0] == 2'b00);
-
- /* These are transaction response flag and data from user-side logic. */
- wire eim_user_ack;
- wire [31: 0] eim_user_data;
-
- /* FSM is reset whenever Chip Select is de-asserted. */
-
- //
- // FSM Transition Logic
- //
- always @(posedge eim_bclk or posedge eim_cs0_n) begin
- //
- if (eim_cs0_n == 1'b1) eim_fsm_state <= EIM_FSM_STATE_INIT;
- //
- else begin
- //
- case (eim_fsm_state)
- //
- // INIT -> WRITE, INIT -> READ
- //
- EIM_FSM_STATE_INIT: begin
- if (eim_write_start_flag) eim_fsm_state <= EIM_FSM_STATE_WRITE_START;
- if (eim_read_start_flag) eim_fsm_state <= EIM_FSM_STATE_READ_START;
- end
- //
- // WRITE
- //
- EIM_FSM_STATE_WRITE_START: eim_fsm_state <= EIM_FSM_STATE_WRITE_LSB;
- //
- EIM_FSM_STATE_WRITE_LSB: eim_fsm_state <= EIM_FSM_STATE_WRITE_MSB;
- //
- EIM_FSM_STATE_WRITE_MSB: eim_fsm_state <= EIM_FSM_STATE_WRITE_WAIT;
- //
- EIM_FSM_STATE_WRITE_WAIT:
- if (eim_user_ack) eim_fsm_state <= EIM_FSM_STATE_WRITE_DONE;
- //
- EIM_FSM_STATE_WRITE_DONE: eim_fsm_state <= EIM_FSM_STATE_INIT;
- //
- // READ
- //
- EIM_FSM_STATE_READ_START: eim_fsm_state <= EIM_FSM_STATE_READ_WAIT;
- //
- EIM_FSM_STATE_READ_WAIT:
- if (eim_user_ack) eim_fsm_state <= EIM_FSM_STATE_READ_READY;
- //
- EIM_FSM_STATE_READ_READY: eim_fsm_state <= EIM_FSM_STATE_READ_LSB;
- //
- EIM_FSM_STATE_READ_LSB: eim_fsm_state <= EIM_FSM_STATE_READ_MSB;
- //
- EIM_FSM_STATE_READ_MSB: eim_fsm_state <= EIM_FSM_STATE_READ_DONE;
- //
- EIM_FSM_STATE_READ_DONE: eim_fsm_state <= EIM_FSM_STATE_INIT;
- //
- //
- //
- default: eim_fsm_state <= EIM_FSM_STATE_INIT;
- //
- endcase
- //
- end
- //
- end
-
-
- //
- // Address Latch
- //
- always @(posedge eim_bclk)
- //
- if ((eim_fsm_state == EIM_FSM_STATE_INIT) && (eim_write_start_flag || eim_read_start_flag))
- eim_addr_latch <= da_ro[15:2];
-
-
- //
- // Additional Write Logic
- //
- always @(posedge eim_bclk)
- //
- if (eim_fsm_state == EIM_FSM_STATE_WRITE_START)
- eim_write_lsb_latch <= da_ro;
-
-
- //
- // Additional Read Logic
- //
-
- /* Note that this stuff operates on falling clock edge, because the cpu
- * samples our bi-directional data bus on rising clock edge.
- */
-
- always @(negedge eim_bclk or posedge eim_cs0_n)
- //
- if (eim_cs0_n == 1'b1) da_di <= {16{1'bX}}; // don't care what to drive
- else begin
- //
- if (eim_fsm_state == EIM_FSM_STATE_READ_LSB) da_di <= eim_user_data[15: 0]; // drive lower 16 bits at first...
- if (eim_fsm_state == EIM_FSM_STATE_READ_MSB) da_di <= eim_user_data[31:16]; // ...then drive upper 16 bits
- //
- end
-
-
- //
- // Wait Logic
- //
-
- /* Note that this stuff operates on falling clock edge, because the cpu
- * samples our WAIT_N flag on rising clock edge.
- */
-
- reg eim_wait_reg = 1'b0;
-
- always @(negedge eim_bclk or posedge eim_cs0_n)
- //
- if (eim_cs0_n == 1'b1) eim_wait_reg <= 1'b0; // clear wait
- else begin
- //
- if (eim_fsm_state == EIM_FSM_STATE_WRITE_START) eim_wait_reg <= 1'b1; // start waiting for write to complete
- if (eim_fsm_state == EIM_FSM_STATE_READ_START) eim_wait_reg <= 1'b1; // start waiting for read to complete
- //
- if (eim_fsm_state == EIM_FSM_STATE_WRITE_DONE) eim_wait_reg <= 1'b0; // write transaction done
- if (eim_fsm_state == EIM_FSM_STATE_READ_READY) eim_wait_reg <= 1'b0; // read transaction done
- //
- if (eim_fsm_state == EIM_FSM_STATE_INIT) eim_wait_reg <= 1'b0; // fsm is idle, no need to wait any more
- //
- end
-
- assign eim_wait_n = ~eim_wait_reg;
-
-
- /* These flags are used to generate 1-cycle pulses to trigger CDC transaction.
- * Note that FSM goes from WRITE_LSB to WRITE_MSB and from READ_START to READ_WAIT
- * unconditionally, so these flags will always be active for 1 cycle only, which
- * is exactly what we need.
- */
-
- wire arbiter_write_req_pulse = (eim_fsm_state == EIM_FSM_STATE_WRITE_LSB) ? 1'b1 : 1'b0;
- wire arbiter_read_req_pulse = (eim_fsm_state == EIM_FSM_STATE_READ_START) ? 1'b1 : 1'b0;
-
- //
- // CDC Block
- //
-
- /* This block is used to transfer request data from BCLK clock domain to SYS_CLK clock domain and
- * then transfer acknowledge from SYS_CLK to BCLK clock domain in return. Af first 1+1+14+32 = 48 bits
- * are transfered, these are: write flag, read flag, address, write data. During read transaction
- * some bogus write data is passed, which is not used later anyway. During read requests 32 bits of data
- * are returned, during write requests 32 bits of bogus data are returned, that are never used later.
- */
-
- eim_arbiter_cdc eim_cdc
- (
- .eim_clk (eim_bclk),
-
- .eim_req (arbiter_write_req_pulse | arbiter_read_req_pulse),
- .eim_ack (eim_user_ack),
-
- .eim_din ({arbiter_write_req_pulse, arbiter_read_req_pulse, eim_addr_latch, da_ro, eim_write_lsb_latch}),
- .eim_dout (eim_user_data),
-
- .sys_clk (sys_clk),
- .sys_addr (sys_addr),
- .sys_wren (sys_wren),
- .sys_data_out (sys_data_out),
- .sys_rden (sys_rden),
- .sys_data_in (sys_data_in)
- );
-
-
-endmodule
+ input wire eim_oe_n; // |
+ output wire eim_wait_n; // |
+
+ input wire sys_clk; // system clock
+
+ output wire [13: 0] sys_addr; // | user bus
+ output wire sys_wren; // |
+ output wire [31: 0] sys_data_out; // |
+ output wire sys_rden; // |
+ input wire [31: 0] sys_data_in; // |
+
+
+ //
+ // Data/Address PHY
+ //
+
+ /* PHY is needed to control bi-directional address/data bus. */
+
+ wire [15: 0] da_ro; // value read from pins
+ reg [15: 0] da_di; // value drives onto pins
+
+ eim_da_phy da_phy
+ (
+ .buf_io (eim_da), // <-- connect directly top-level port
+ .buf_di (da_di),
+ .buf_ro (da_ro),
+ .buf_t (eim_oe_n) // <-- driven by EIM directly
+ );
+
+
+ //
+ // FSM
+ //
+ localparam EIM_FSM_STATE_INIT = 5'b0_0_000; // arbiter is idle
+
+ localparam EIM_FSM_STATE_WRITE_START = 5'b1_1_000; // got address to write at
+ localparam EIM_FSM_STATE_WRITE_LSB = 5'b1_1_001; // got lower 16 bits of data to write
+ localparam EIM_FSM_STATE_WRITE_MSB = 5'b1_1_010; // got upper 16 bits of data to write
+ localparam EIM_FSM_STATE_WRITE_WAIT = 5'b1_1_100; // request to user-side logic sent
+ localparam EIM_FSM_STATE_WRITE_DONE = 5'b1_1_111; // user-side logic acknowledged transaction
+
+ localparam EIM_FSM_STATE_READ_START = 5'b1_0_000; // got address to read from
+ localparam EIM_FSM_STATE_READ_WAIT = 5'b1_0_100; // request to user-side logic sent
+ localparam EIM_FSM_STATE_READ_READY = 5'b1_0_011; // got acknowledge from user logic
+ localparam EIM_FSM_STATE_READ_LSB = 5'b1_0_001; // returned lower 16 bits to master
+ localparam EIM_FSM_STATE_READ_MSB = 5'b1_0_010; // returned upper 16 bits to master
+ localparam EIM_FSM_STATE_READ_DONE = 5'b1_0_111; // transaction complete
+
+ reg [ 4: 0] eim_fsm_state = EIM_FSM_STATE_INIT; // fsm state
+ reg [13: 0] eim_addr_latch = {14{1'bX}}; // transaction address
+ reg [15: 0] eim_write_lsb_latch = {16{1'bX}}; // lower 16 bits of data to write
+
+ /* These flags are used to wake up from INIT state. */
+ wire eim_write_start_flag = (eim_lba_n == 1'b0) && (eim_wr_n == 1'b0) && (da_ro[1:0] == 2'b00);
+ wire eim_read_start_flag = (eim_lba_n == 1'b0) && (eim_wr_n == 1'b1) && (da_ro[1:0] == 2'b00);
+
+ /* These are transaction response flag and data from user-side logic. */
+ wire eim_user_ack;
+ wire [31: 0] eim_user_data;
+
+ /* FSM is reset whenever Chip Select is de-asserted. */
+
+ //
+ // FSM Transition Logic
+ //
+ always @(posedge eim_bclk or posedge eim_cs0_n) begin
+ //
+ if (eim_cs0_n == 1'b1) eim_fsm_state <= EIM_FSM_STATE_INIT;
+ //
+ else begin
+ //
+ case (eim_fsm_state)
+ //
+ // INIT -> WRITE, INIT -> READ
+ //
+ EIM_FSM_STATE_INIT: begin
+ if (eim_write_start_flag) eim_fsm_state <= EIM_FSM_STATE_WRITE_START;
+ if (eim_read_start_flag) eim_fsm_state <= EIM_FSM_STATE_READ_START;
+ end
+ //
+ // WRITE
+ //
+ EIM_FSM_STATE_WRITE_START: eim_fsm_state <= EIM_FSM_STATE_WRITE_LSB;
+ //
+ EIM_FSM_STATE_WRITE_LSB: eim_fsm_state <= EIM_FSM_STATE_WRITE_MSB;
+ //
+ EIM_FSM_STATE_WRITE_MSB: eim_fsm_state <= EIM_FSM_STATE_WRITE_WAIT;
+ //
+ EIM_FSM_STATE_WRITE_WAIT:
+ if (eim_user_ack) eim_fsm_state <= EIM_FSM_STATE_WRITE_DONE;
+ //
+ EIM_FSM_STATE_WRITE_DONE: eim_fsm_state <= EIM_FSM_STATE_INIT;
+ //
+ // READ
+ //
+ EIM_FSM_STATE_READ_START: eim_fsm_state <= EIM_FSM_STATE_READ_WAIT;
+ //
+ EIM_FSM_STATE_READ_WAIT:
+ if (eim_user_ack) eim_fsm_state <= EIM_FSM_STATE_READ_READY;
+ //
+ EIM_FSM_STATE_READ_READY: eim_fsm_state <= EIM_FSM_STATE_READ_LSB;
+ //
+ EIM_FSM_STATE_READ_LSB: eim_fsm_state <= EIM_FSM_STATE_READ_MSB;
+ //
+ EIM_FSM_STATE_READ_MSB: eim_fsm_state <= EIM_FSM_STATE_READ_DONE;
+ //
+ EIM_FSM_STATE_READ_DONE: eim_fsm_state <= EIM_FSM_STATE_INIT;
+ //
+ //
+ //
+ default: eim_fsm_state <= EIM_FSM_STATE_INIT;
+ //
+ endcase
+ //
+ end
+ //
+ end
+
+
+ //
+ // Address Latch
+ //
+ always @(posedge eim_bclk)
+ //
+ if ((eim_fsm_state == EIM_FSM_STATE_INIT) && (eim_write_start_flag || eim_read_start_flag))
+ eim_addr_latch <= da_ro[15:2];
+
+
+ //
+ // Additional Write Logic
+ //
+ always @(posedge eim_bclk)
+ //
+ if (eim_fsm_state == EIM_FSM_STATE_WRITE_START)
+ eim_write_lsb_latch <= da_ro;
+
+
+ //
+ // Additional Read Logic
+ //
+
+ /* Note that this stuff operates on falling clock edge, because the cpu
+ * samples our bi-directional data bus on rising clock edge.
+ */
+
+ always @(negedge eim_bclk or posedge eim_cs0_n)
+ //
+ if (eim_cs0_n == 1'b1) da_di <= {16{1'bX}}; // don't care what to drive
+ else begin
+ //
+ if (eim_fsm_state == EIM_FSM_STATE_READ_LSB) da_di <= eim_user_data[15: 0]; // drive lower 16 bits at first...
+ if (eim_fsm_state == EIM_FSM_STATE_READ_MSB) da_di <= eim_user_data[31:16]; // ...then drive upper 16 bits
+ //
+ end
+
+
+ //
+ // Wait Logic
+ //
+
+ /* Note that this stuff operates on falling clock edge, because the cpu
+ * samples our WAIT_N flag on rising clock edge.
+ */
+
+ reg eim_wait_reg = 1'b0;
+
+ always @(negedge eim_bclk or posedge eim_cs0_n)
+ //
+ if (eim_cs0_n == 1'b1) eim_wait_reg <= 1'b0; // clear wait
+ else begin
+ //
+ if (eim_fsm_state == EIM_FSM_STATE_WRITE_START) eim_wait_reg <= 1'b1; // start waiting for write to complete
+ if (eim_fsm_state == EIM_FSM_STATE_READ_START) eim_wait_reg <= 1'b1; // start waiting for read to complete
+ //
+ if (eim_fsm_state == EIM_FSM_STATE_WRITE_DONE) eim_wait_reg <= 1'b0; // write transaction done
+ if (eim_fsm_state == EIM_FSM_STATE_READ_READY) eim_wait_reg <= 1'b0; // read transaction done
+ //
+ if (eim_fsm_state == EIM_FSM_STATE_INIT) eim_wait_reg <= 1'b0; // fsm is idle, no need to wait any more
+ //
+ end
+
+ assign eim_wait_n = ~eim_wait_reg;
+
+
+ /* These flags are used to generate 1-cycle pulses to trigger CDC transaction.
+ * Note that FSM goes from WRITE_LSB to WRITE_MSB and from READ_START to READ_WAIT
+ * unconditionally, so these flags will always be active for 1 cycle only, which
+ * is exactly what we need.
+ */
+
+ wire arbiter_write_req_pulse = (eim_fsm_state == EIM_FSM_STATE_WRITE_LSB) ? 1'b1 : 1'b0;
+ wire arbiter_read_req_pulse = (eim_fsm_state == EIM_FSM_STATE_READ_START) ? 1'b1 : 1'b0;
+
+ //
+ // CDC Block
+ //
+
+ /* This block is used to transfer request data from BCLK clock domain to SYS_CLK clock domain and
+ * then transfer acknowledge from SYS_CLK to BCLK clock domain in return. Af first 1+1+14+32 = 48 bits
+ * are transfered, these are: write flag, read flag, address, write data. During read transaction
+ * some bogus write data is passed, which is not used later anyway. During read requests 32 bits of data
+ * are returned, during write requests 32 bits of bogus data are returned, that are never used later.
+ */
+
+ eim_arbiter_cdc eim_cdc
+ (
+ .eim_clk (eim_bclk),
+
+ .eim_req (arbiter_write_req_pulse | arbiter_read_req_pulse),
+ .eim_ack (eim_user_ack),
+
+ .eim_din ({arbiter_write_req_pulse, arbiter_read_req_pulse, eim_addr_latch, da_ro, eim_write_lsb_latch}),
+ .eim_dout (eim_user_data),
+
+ .sys_clk (sys_clk),
+ .sys_addr (sys_addr),
+ .sys_wren (sys_wren),
+ .sys_data_out (sys_data_out),
+ .sys_rden (sys_rden),
+ .sys_data_in (sys_data_in)
+ );
+
+
+endmodule
diff --git a/rtl/src/verilog/eim_da_phy.v b/rtl/src/verilog/eim_da_phy.v
index 9fe0c3b..9b76d3b 100644
--- a/rtl/src/verilog/eim_da_phy.v
+++ b/rtl/src/verilog/eim_da_phy.v
@@ -1,47 +1,47 @@
-`timescale 1ns / 1ps
-
-module eim_da_phy
- (
- buf_io,
- buf_di, buf_ro,
- buf_t
- );
-
- //
- // Parameters
- //
- parameter BUS_WIDTH = 16;
-
- //
- // Ports
- //
- inout wire [BUS_WIDTH-1:0] buf_io; // connect directly to top-level pins
- input wire [BUS_WIDTH-1:0] buf_di; // drive input (value driven onto pins)
- output wire [BUS_WIDTH-1:0] buf_ro; // receiver output (value read from pins)
- input wire buf_t; // tristate control (driver is disabled during tristate)
-
- //
- // IOBUFs
- //
+`timescale 1ns / 1ps
+
+module eim_da_phy
+ (
+ buf_io,
+ buf_di, buf_ro,
+ buf_t
+ );
+
+ //
+ // Parameters
+ //
+ parameter BUS_WIDTH = 16;
+
+ //
+ // Ports
+ //
+ inout wire [BUS_WIDTH-1:0] buf_io; // connect directly to top-level pins
+ input wire [BUS_WIDTH-1:0] buf_di; // drive input (value driven onto pins)
+ output wire [BUS_WIDTH-1:0] buf_ro; // receiver output (value read from pins)
+ input wire buf_t; // tristate control (driver is disabled during tristate)
+
+ //
+ // IOBUFs
+ //
genvar i;
- generate for (i=0; i<BUS_WIDTH; i=i+1)
+ generate for (i=0; i<BUS_WIDTH; i=i+1)
begin: eim_da
- //
- IOBUF #
- (
+ //
+ IOBUF #
+ (
.IOSTANDARD ("LVCMOS33"),
.DRIVE (12),
.SLEW ("FAST")
- )
- IOBUF_inst
- (
+ )
+ IOBUF_inst
+ (
.IO (buf_io[i]),
.O (buf_ro[i]),
.I (buf_di[i]),
.T (buf_t)
- );
+ );
//
end
- endgenerate
-
-endmodule
+ endgenerate
+
+endmodule
diff --git a/rtl/src/verilog/novena_baseline_top.v b/rtl/src/verilog/novena_baseline_top.v
index a62f311..57ef434 100644
--- a/rtl/src/verilog/novena_baseline_top.v
+++ b/rtl/src/verilog/novena_baseline_top.v
@@ -1,7 +1,7 @@
-`timescale 1ns / 1ps
-
-module novena_baseline_top
- (
+`timescale 1ns / 1ps
+
+module novena_baseline_top
+ (
gclk_p_pin, gclk_n_pin,
eim_bclk, eim_cs0_n, eim_da,
@@ -10,13 +10,13 @@ module novena_baseline_top
reset_mcu_b_pin,
apoptosis_pin,
- led_pin
- );
-
+ led_pin
+ );
+
//
// Top-Levl Ports
//
- input wire gclk_p_pin; // general-purpose 50 MHz LVDS clock
+ input wire gclk_p_pin; // general-purpose 50 MHz LVDS clock
input wire gclk_n_pin; //
input wire eim_bclk; // burst clock from cpu
@@ -27,106 +27,106 @@ module novena_baseline_top
input wire eim_oe_n; // output enable signal (active low)
output wire eim_wait_n; // wait signal (active low)
- input wire reset_mcu_b_pin; // this must be configured as input w/pullup
+ input wire reset_mcu_b_pin; // this must be configured as input w/pullup
// not to kill the cpu after configuration
output wire apoptosis_pin; // not used, tied to 0
- output wire led_pin; // visual activity indicator
-
-
- //
- // Clock Manager
- //
-
- /* Clock manager is used to buffer BCLK and also generate SYS_CLK from GCLK. */
-
- wire sys_clk;
- wire sys_rst;
-
- wire eim_bclk_buf;
-
- novena_clkmgr clkmgr
- (
- .gclk_p (gclk_p_pin),
- .gclk_n (gclk_n_pin),
-
- .reset_mcu_b (reset_mcu_b_pin),
-
- .sys_clk (sys_clk),
- .sys_rst (sys_rst),
-
- .bclk_in (eim_bclk),
- .bclk_out (eim_bclk_buf)
- );
-
-
- //
- // EIM Arbiter
- //
-
- /* EIM arbiter handles EIM access and transfers it into `sys_clk' clock domain. */
-
+ output wire led_pin; // visual activity indicator
+
+
+ //
+ // Clock Manager
+ //
+
+ /* Clock manager is used to buffer BCLK and also generate SYS_CLK from GCLK. */
+
+ wire sys_clk;
+ wire sys_rst;
+
+ wire eim_bclk_buf;
+
+ novena_clkmgr clkmgr
+ (
+ .gclk_p (gclk_p_pin),
+ .gclk_n (gclk_n_pin),
+
+ .reset_mcu_b (reset_mcu_b_pin),
+
+ .sys_clk (sys_clk),
+ .sys_rst (sys_rst),
+
+ .bclk_in (eim_bclk),
+ .bclk_out (eim_bclk_buf)
+ );
+
+
+ //
+ // EIM Arbiter
+ //
+
+ /* EIM arbiter handles EIM access and transfers it into `sys_clk' clock domain. */
+
wire [13: 0] sys_eim_addr;
- wire sys_eim_wr;
+ wire sys_eim_wr;
wire sys_eim_rd;
wire [31: 0] sys_eim_dout;
- wire [31: 0] sys_eim_din;
-
- eim_arbiter eim
- (
- .eim_bclk (eim_bclk_buf),
- .eim_cs0_n (eim_cs0_n),
+ wire [31: 0] sys_eim_din;
+
+ eim_arbiter eim
+ (
+ .eim_bclk (eim_bclk_buf),
+ .eim_cs0_n (eim_cs0_n),
.eim_da (eim_da),
- .eim_lba_n (eim_lba_n),
+ .eim_lba_n (eim_lba_n),
.eim_wr_n (eim_wr_n),
- .eim_oe_n (eim_oe_n),
- .eim_wait_n (eim_wait_n),
-
- .sys_clk (sys_clk),
-
- .sys_addr (sys_eim_addr),
- .sys_wren (sys_eim_wr),
- .sys_data_out (sys_eim_dout),
- .sys_rden (sys_eim_rd),
- .sys_data_in (sys_eim_din)
- );
-
-
- //
- // Core Selector (MUX)
- //
-
- /* This multiplexor is used to map demo adder registers somewhere into EIM address space. */
-
- core_selector mux
- (
- .sys_clk (sys_clk),
- .sys_rst (sys_rst),
-
- .sys_eim_addr (sys_eim_addr),
- .sys_eim_wr (sys_eim_wr),
- .sys_eim_rd (sys_eim_rd),
-
- .sys_eim_dout (sys_eim_dout),
- .sys_eim_din (sys_eim_din)
- );
-
-
- //
- // LED Driver
- //
- eim_indicator led
- (
- .sys_clk (sys_clk),
- .sys_rst (sys_rst),
- .eim_active (sys_eim_wr | sys_eim_rd),
- .led_out (led_pin)
- );
-
-
- //
- // Unused
- //
- assign apoptosis_pin = 1'b0;
-
-
-endmodule
+ .eim_oe_n (eim_oe_n),
+ .eim_wait_n (eim_wait_n),
+
+ .sys_clk (sys_clk),
+
+ .sys_addr (sys_eim_addr),
+ .sys_wren (sys_eim_wr),
+ .sys_data_out (sys_eim_dout),
+ .sys_rden (sys_eim_rd),
+ .sys_data_in (sys_eim_din)
+ );
+
+
+ //
+ // Core Selector (MUX)
+ //
+
+ /* This multiplexor is used to map demo adder registers somewhere into EIM address space. */
+
+ core_selector mux
+ (
+ .sys_clk (sys_clk),
+ .sys_rst (sys_rst),
+
+ .sys_eim_addr (sys_eim_addr),
+ .sys_eim_wr (sys_eim_wr),
+ .sys_eim_rd (sys_eim_rd),
+
+ .sys_eim_dout (sys_eim_dout),
+ .sys_eim_din (sys_eim_din)
+ );
+
+
+ //
+ // LED Driver
+ //
+ eim_indicator led
+ (
+ .sys_clk (sys_clk),
+ .sys_rst (sys_rst),
+ .eim_active (sys_eim_wr | sys_eim_rd),
+ .led_out (led_pin)
+ );
+
+
+ //
+ // Unused
+ //
+ assign apoptosis_pin = 1'b0;
+
+
+endmodule
diff --git a/rtl/src/verilog/novena_clkmgr.v b/rtl/src/verilog/novena_clkmgr.v
index 2f8c02f..5713383 100644
--- a/rtl/src/verilog/novena_clkmgr.v
+++ b/rtl/src/verilog/novena_clkmgr.v
@@ -1,100 +1,100 @@
-`timescale 1ns / 1ps
-
-module novena_clkmgr
- (
+`timescale 1ns / 1ps
+
+module novena_clkmgr
+ (
gclk_p, gclk_n,
reset_mcu_b,
- sys_clk, sys_rst,
- bclk_in, bclk_out
- );
-
- //
- // Ports
- //
- input wire gclk_p; // signal from clock pins
- input wire gclk_n; //
-
- input wire reset_mcu_b; // cpu reset (async)
-
- output wire sys_clk; // buffered system clock output
- output wire sys_rst; // system reset output (sync)
-
- input wire bclk_in; // signal from clock pin
- output wire bclk_out; // buffered clock output
-
-
- //
- // IBUFGDS
- //
- (* BUFFER_TYPE="NONE" *)
- wire gclk;
-
+ sys_clk, sys_rst,
+ bclk_in, bclk_out
+ );
+
+ //
+ // Ports
+ //
+ input wire gclk_p; // signal from clock pins
+ input wire gclk_n; //
+
+ input wire reset_mcu_b; // cpu reset (async)
+
+ output wire sys_clk; // buffered system clock output
+ output wire sys_rst; // system reset output (sync)
+
+ input wire bclk_in; // signal from clock pin
+ output wire bclk_out; // buffered clock output
+
+
+ //
+ // IBUFGDS
+ //
+ (* BUFFER_TYPE="NONE" *)
+ wire gclk;
+
IBUFGDS IBUFGDS_gclk
(
.I (gclk_p),
.IB (gclk_n),
.O (gclk)
- );
-
-
- //
- // DCM
- //
- wire dcm_reset; // dcm reset
- wire dcm_locked; // output clock valid
- wire gclk_missing; // no input clock
-
- clkmgr_dcm dcm
- (
- .CLK_IN1 (gclk),
- .RESET (dcm_reset),
- .INPUT_CLK_STOPPED (gclk_missing),
-
- .CLK_OUT1 (sys_clk),
- .CLK_VALID (dcm_locked)
- );
-
-
+ );
+
+
+ //
+ // DCM
+ //
+ wire dcm_reset; // dcm reset
+ wire dcm_locked; // output clock valid
+ wire gclk_missing; // no input clock
+
+ clkmgr_dcm dcm
+ (
+ .CLK_IN1 (gclk),
+ .RESET (dcm_reset),
+ .INPUT_CLK_STOPPED (gclk_missing),
+
+ .CLK_OUT1 (sys_clk),
+ .CLK_VALID (dcm_locked)
+ );
+
+
//
// DCM Reset Logic
- //
-
- /* DCM should be reset on power-up, when input clock is stopped or when the CPU gets reset. */
-
- reg [15: 0] dcm_rst_shreg = {16{1'b1}}; // 16-bit shift register
-
+ //
+
+ /* DCM should be reset on power-up, when input clock is stopped or when the CPU gets reset. */
+
+ reg [15: 0] dcm_rst_shreg = {16{1'b1}}; // 16-bit shift register
+
always @(posedge gclk or negedge reset_mcu_b or posedge gclk_missing)
//
if ((reset_mcu_b == 1'b0) || (gclk_missing == 1'b1)) dcm_rst_shreg <= {16{1'b1}};
else dcm_rst_shreg <= {dcm_rst_shreg[14:0], 1'b0};
-
- assign dcm_reset = dcm_rst_shreg[15];
-
-
+
+ assign dcm_reset = dcm_rst_shreg[15];
+
+
//
// System Reset Logic
- //
-
- /* System reset is asserted for 16 cycles whenever DCM aquires lock. */
-
+ //
+
+ /* System reset is asserted for 16 cycles whenever DCM aquires lock. */
+
reg [15: 0] sys_rst_shreg = {16{1'b1}}; // 16-bit shift register
-
+
always @(posedge sys_clk or negedge reset_mcu_b or posedge gclk_missing or negedge dcm_locked)
//
if ((reset_mcu_b == 1'b0) || (gclk_missing == 1'b1) || (dcm_locked == 1'b0)) sys_rst_shreg <= {16{1'b1}};
- else if (dcm_locked == 1'b1) sys_rst_shreg <= {sys_rst_shreg[14:0], 1'b0};
-
- assign sys_rst = sys_rst_shreg[15];
-
-
- //
- // BCLK BUFG
- //
- BUFG BUFG_BCLK
- (
- .I (bclk_in),
- .O (bclk_out)
- );
-
-
-endmodule
+ else if (dcm_locked == 1'b1) sys_rst_shreg <= {sys_rst_shreg[14:0], 1'b0};
+
+ assign sys_rst = sys_rst_shreg[15];
+
+
+ //
+ // BCLK BUFG
+ //
+ BUFG BUFG_BCLK
+ (
+ .I (bclk_in),
+ .O (bclk_out)
+ );
+
+
+endmodule