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-rw-r--r--fpga/usrp2/control_lib/ram_loader.v460
1 files changed, 248 insertions, 212 deletions
diff --git a/fpga/usrp2/control_lib/ram_loader.v b/fpga/usrp2/control_lib/ram_loader.v
index cb67de739..c53ea7aa7 100644
--- a/fpga/usrp2/control_lib/ram_loader.v
+++ b/fpga/usrp2/control_lib/ram_loader.v
@@ -1,225 +1,261 @@
+module ram_loader
+ #(parameter AWIDTH=16, RAM_SIZE=16384)
+ (
+ // Wishbone I/F and clock domain
+ input wb_clk,
+ input dsp_clk,
+ input ram_loader_rst,
+ output wire [31:0] wb_dat,
+ output wire [AWIDTH-1:0] wb_adr,
+ output wb_stb,
+ output reg [3:0] wb_sel,
+ output wb_we,
+ output reg ram_loader_done,
+ // CPLD signals and clock domain
+ input cpld_clk,
+ input cpld_din,
+ output reg cpld_start,
+ output reg cpld_mode,
+ output reg cpld_done,
+ input cpld_detached
+ );
-// Adapted from VHDL code in spi_boot by Arnim Legauer
-// Added a full wishbone master interface (32-bit)
-
-module ram_loader #(parameter AWIDTH=16, RAM_SIZE=16384)
- (input clk_i, input rst_i,
- // CPLD Interface
- input cfg_clk_i, input cfg_data_i,
- output start_o, output mode_o, output done_o,
- input detached_i,
- // Wishbone interface
- output wire [31:0] wb_dat_o,
- output reg [AWIDTH-1:0] wb_adr_o,
- output wb_stb_o,
- output wb_cyc_o,
- output reg [3:0] wb_sel_o,
- output reg wb_we_o,
- input wb_ack_i,
- output ram_loader_done_o);
+ localparam S0 = 0;
+ localparam S1 = 1;
+ localparam S2 = 2;
+ localparam S3 = 3;
+ localparam S4 = 4;
+ localparam S5 = 5;
+ localparam S6 = 6;
+ localparam RESET = 7;
- // FSM to control start signal, clocked on main clock
- localparam FSM1_WAIT_DETACH = 2'b00;
- localparam FSM1_CHECK_NO_DONE = 2'b01;
- localparam FSM1_WAIT_DONE = 2'b10;
-
- reg [1:0] start_fsm_q, start_fsm_s;
- reg start_q, enable_q, start_s, enable_s;
- reg done_q, done_s;
+ localparam WB_IDLE = 0;
+ localparam WB_WRITE = 1;
+
+
+ reg [AWIDTH+2:0] count; // 3 LSB's count bits in, the MSB's generate the Wishbone address
+ reg [6:0] shift_reg;
+ reg [7:0] data_reg;
+ reg sampled_clk;
+ reg sampled_clk_meta;
+ reg sampled_din;
+ reg inc_count;
+ reg load_data_reg;
+ reg shift;
+ reg wb_state, wb_next_state;
+ reg [2:0] state, next_state;
+
+ //
+ // CPLD clock doesn't free run and is approximately 12.5MHz.
+ // Use 50MHz Wishbone clock to sample it as a signal and avoid having
+ // an extra clock domain for no reason.
+ //
+
+ always @(posedge dsp_clk or posedge ram_loader_rst)
+ if (ram_loader_rst)
+ begin
+ sampled_clk_meta <= 1'b0;
+ sampled_clk <= 1'b0;
+ sampled_din <= 1'b0;
+ count <= 'h7FFF8; // Initialize so that address will be 0 when first byte fully received.
+ data_reg <= 0;
+ shift_reg <= 0;
+ end
+ else
+ begin
+ sampled_clk_meta <= cpld_clk;
+ sampled_clk <= sampled_clk_meta;
+ sampled_din <= cpld_din;
+ if (inc_count)
+ count <= count + 1'b1;
+ if (load_data_reg)
+ data_reg <= {shift_reg,sampled_din};
+ if (shift)
+ shift_reg <= {shift_reg[5:0],sampled_din};
+ end // else: !if(ram_loader_rst)
- always @(posedge clk_i or posedge rst_i)
- if(rst_i)
- begin
- start_fsm_q <= FSM1_WAIT_DETACH;
- start_q <= 1'b0;
- enable_q <= 1'b0;
- end
+
+ always @(posedge dsp_clk or posedge ram_loader_rst)
+ if (ram_loader_rst)
+ state <= RESET;
else
- begin
- start_fsm_q <= start_fsm_s;
- enable_q <= enable_s;
- start_q <= start_s;
- end // else: !if(rst_i)
-
+ state <= next_state;
+
+
always @*
- case(start_fsm_q)
- FSM1_WAIT_DETACH:
- if(detached_i == 1'b1)
- begin
- start_fsm_s <= FSM1_CHECK_NO_DONE;
- enable_s <= 1'b1;
- start_s <= 1'b1;
- end
- else
- begin
- start_fsm_s <= FSM1_WAIT_DETACH;
- enable_s <= enable_q;
- start_s <= start_q;
- end // else: !if(detached_i == 1'b1)
- FSM1_CHECK_NO_DONE:
- if(~done_q)
- begin
- start_fsm_s <= FSM1_WAIT_DONE;
- enable_s <= enable_q;
- start_s <= start_q;
- end
- else
- begin
- start_fsm_s <= FSM1_CHECK_NO_DONE;
- enable_s <= enable_q;
- start_s <= start_q;
- end // else: !if(~done_q)
- FSM1_WAIT_DONE:
- if(done_q)
- begin
- start_fsm_s <= FSM1_WAIT_DETACH;
- enable_s <= 1'b0;
- start_s <= 1'b0;
- end
- else
- begin
- start_fsm_s <= FSM1_WAIT_DONE;
- enable_s <= enable_q;
- start_s <= start_q;
- end // else: !if(done_q)
- default:
- begin
- start_fsm_s <= FSM1_WAIT_DETACH;
- enable_s <= enable_q;
- start_s <= start_q;
- end // else: !if(done_q)
- endcase // case(start_fsm_q)
-
- // FSM running on data clock
-
- localparam FSM2_IDLE = 3'b000;
- localparam FSM2_WE_ON = 3'b001;
- localparam FSM2_WE_OFF = 3'b010;
- localparam FSM2_INC_ADDR1 = 3'b011;
- localparam FSM2_INC_ADDR2 = 3'b100;
- localparam FSM2_FINISHED = 3'b101;
-
- reg [AWIDTH-1:0] addr_q;
- reg [7:0] shift_dat_q, ser_dat_q;
- reg [2:0] bit_q, fsm_q, fsm_s;
- reg bit_ovfl_q, ram_we_s, ram_we_q, mode_q, mode_s, inc_addr_s;
-
- always @(posedge cfg_clk_i or posedge rst_i)
- if(rst_i)
- begin
- addr_q <= 0;
- shift_dat_q <= 8'd0;
- ser_dat_q <= 8'd0;
- bit_q <= 3'd0;
- bit_ovfl_q <= 1'b0;
- fsm_q <= FSM2_IDLE;
- ram_we_q <= 1'b0;
- done_q <= 1'b0;
- mode_q <= 1'b0;
- end
+ begin
+ // Defaults
+ next_state = state;
+ cpld_start = 1'b0;
+ shift = 1'b0;
+ inc_count = 0;
+ load_data_reg = 1'b0;
+ ram_loader_done = 1'b0;
+ cpld_mode = 1'b0;
+ cpld_done = 1'b1;
+
+
+
+ case (state) //synthesis parallel_case full_case
+ // After reset wait until CPLD indicates its detached.
+ RESET: begin
+ if (cpld_detached)
+ next_state = S0;
+ else
+ next_state = RESET;
+ end
+
+ // Assert cpld_start to signal the CPLD its to start sending serial clock and data.
+ // Assume cpld_clk is low as we transition into search for first rising edge
+ S0: begin
+ cpld_start = 1'b1;
+ cpld_done = 1'b0;
+ if (~cpld_detached)
+ next_state = S2;
+ else
+ next_state = S0;
+ end
+
+ //
+ S1: begin
+ cpld_start = 1'b1;
+ cpld_done = 1'b0;
+ if (sampled_clk)
+ begin
+ // Found rising edge on cpld_clk.
+ if (count[2:0] == 3'b111)
+ // Its the last bit of a byte, send it out to the Wishbone bus.
+ begin
+ load_data_reg = 1'b1;
+ inc_count = 1'b1;
+ end
+ else
+ // Shift databit into LSB of shift register and increment count
+ begin
+ shift = 1'b1;
+ inc_count = 1'b1;
+ end // else: !if(count[2:0] == 3'b111)
+ next_state = S2;
+ end // if (sampled_clk)
+ else
+ next_state = S1;
+ end // case: S1
+
+ //
+ S2: begin
+ cpld_start = 1'b1;
+ cpld_done = 1'b0;
+ if (~sampled_clk)
+ // Found negative edge of clock
+ if (count[AWIDTH+2:3] == RAM_SIZE-1) // NOTE need to change this constant
+ // All firmware now downloaded
+ next_state = S3;
+ else
+ next_state = S1;
+ else
+ next_state = S2;
+ end // case: S2
+
+ // Now that terminal count is reached and all firmware is downloaded signal CPLD that download is done
+ // and that mode is now SPI mode.
+ S3: begin
+ if (sampled_clk)
+ begin
+ cpld_mode = 1'b1;
+ cpld_done = 1'b1;
+ next_state = S4;
+ end
+ else
+ next_state = S3;
+ end
+
+ // Search for negedge of cpld_clk whilst keeping done sequence asserted.
+ // Keep done assserted
+ S4: begin
+ cpld_mode = 1'b1;
+ cpld_done = 1'b1;
+ if (~sampled_clk)
+ next_state = S5;
+ else
+ next_state = S4;
+ end
+
+ // Search for posedge of cpld_clk whilst keeping done sequence asserted.
+ S5: begin
+ cpld_mode = 1'b1;
+ cpld_done = 1'b1;
+ if (sampled_clk)
+ next_state = S6;
+ else
+ next_state = S5;
+ end
+
+ // Stay in this state until reset/power down
+ S6: begin
+ ram_loader_done = 1'b1;
+ cpld_done = 1'b1;
+ cpld_mode = 1'b1;
+ next_state = S6;
+ end
+
+ endcase // case(state)
+ end
+
+ always @(posedge dsp_clk or posedge ram_loader_rst)
+ if (ram_loader_rst)
+ wb_state <= WB_IDLE;
else
- begin
- if(inc_addr_s)
- addr_q <= addr_q + 1;
- if(enable_q)
- begin
- bit_q <= bit_q + 1;
- bit_ovfl_q <= (bit_q == 3'd7);
- shift_dat_q[0] <= cfg_data_i;
- shift_dat_q[7:1] <= shift_dat_q[6:0];
- end
- if(bit_ovfl_q)
- ser_dat_q <= shift_dat_q;
-
- fsm_q <= fsm_s;
-
- ram_we_q <= ram_we_s;
-
- if(done_s)
- done_q <= 1'b1;
- mode_q <= mode_s;
- end // else: !if(rst_i)
+ wb_state <= wb_next_state;
+ reg do_write;
+ wire empty, full;
+
always @*
begin
- inc_addr_s <= 1'b0;
- ram_we_s <= 1'b0;
- done_s <= 1'b0;
- fsm_s <= FSM2_IDLE;
- mode_s <= 1'b0;
-
- case(fsm_q)
- FSM2_IDLE :
- if(start_q)
- if(bit_ovfl_q)
- fsm_s <= FSM2_WE_ON;
- FSM2_WE_ON:
- begin
- ram_we_s <= 1'b1;
- fsm_s <= FSM2_WE_OFF;
- end
- FSM2_WE_OFF:
- begin
- ram_we_s <= 1'b1;
- fsm_s <= FSM2_INC_ADDR1;
- end
- FSM2_INC_ADDR1:
- fsm_s <= FSM2_INC_ADDR2;
- FSM2_INC_ADDR2:
- if(addr_q == (RAM_SIZE-1))
- //if(&addr_q)
- begin
- fsm_s <= FSM2_FINISHED;
- done_s <= 1'b1;
- mode_s <= 1'b1;
- end
- else
- begin
- inc_addr_s <= 1'b1;
- fsm_s <= FSM2_IDLE;
- end // else: !if(&addr_q)
- FSM2_FINISHED:
- begin
- fsm_s <= FSM2_FINISHED;
- mode_s <= 1'b1;
- end
- endcase // case(fsm_q)
+ wb_next_state = wb_state;
+ do_write = 1'b0;
+
+ case (wb_state) //synthesis full_case parallel_case
+ //
+ WB_IDLE: begin
+ if (load_data_reg)
+ // Data reg will load ready to write wishbone @ next clock edge
+ wb_next_state = WB_WRITE;
+ else
+ wb_next_state = WB_IDLE;
+ end
+
+ // Drive address and data onto wishbone.
+ WB_WRITE: begin
+ do_write = 1'b1;
+ if (~full)
+ wb_next_state = WB_IDLE;
+ else
+ wb_next_state = WB_WRITE;
+ end
+
+ endcase // case(wb_state)
end // always @ *
- assign start_o = start_q;
- assign mode_o = mode_q;
- assign done_o = start_q ? done_q : 1'b1;
- wire [AWIDTH-1:0] ram_addr = addr_q;
- wire [7:0] ram_data = ser_dat_q;
- assign ram_loader_done_o = (fsm_q == FSM2_FINISHED);
-
- // wishbone master, only writes
- reg [7:0] dat_holder;
- assign wb_dat_o = {4{dat_holder}};
- assign wb_stb_o = wb_we_o;
- assign wb_cyc_o = wb_we_o;
+ wire [1:0] count_out;
+ wire [7:0] data_out;
+
+ fifo_xlnx_16x40_2clk crossclk
+ (.rst(ram_loader_rst),
+ .wr_clk(dsp_clk), .din({count[4:3],count[AWIDTH+2:3],data_reg}), .wr_en(do_write), .full(full),
+ .rd_clk(wb_clk), .dout({count_out,wb_adr,data_out}), .rd_en(~empty), .empty(empty));
+
+ assign wb_dat = {4{data_out}};
+
+ always @*
+ case(count_out[1:0]) //synthesis parallel_case full_case
+ 2'b00 : wb_sel = 4'b1000;
+ 2'b01 : wb_sel = 4'b0100;
+ 2'b10 : wb_sel = 4'b0010;
+ 2'b11 : wb_sel = 4'b0001;
+ endcase
+
+ assign wb_we = ~empty;
+ assign wb_stb = ~empty;
- always @(posedge clk_i or posedge rst_i)
- if(rst_i)
- begin
- dat_holder <= 8'd0;
- wb_adr_o <= 0;
- wb_sel_o <= 4'b0000;
- wb_we_o <= 1'b0;
- end
- else if(ram_we_q)
- begin
- dat_holder <= ram_data;
- wb_adr_o <= ram_addr;
- wb_we_o <= 1'b1;
- case(ram_addr[1:0]) // Big Endian
- 2'b00 : wb_sel_o <= 4'b1000;
- 2'b01 : wb_sel_o <= 4'b0100;
- 2'b10 : wb_sel_o <= 4'b0010;
- 2'b11 : wb_sel_o <= 4'b0001;
- endcase // case(ram_addr[1:0])
- end // if (ram_we_q)
- else if(wb_ack_i)
- wb_we_o <= 1'b0;
-
endmodule // ram_loader
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