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Separating clocks for tx/rx

- more modular, understandable, reusable
This commit is contained in:
Andreas Olofsson 2015-10-07 19:08:32 -04:00
parent 947a804c62
commit 4477f55cf5
2 changed files with 518 additions and 0 deletions

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elink/hdl/erx_clocks.v Normal file
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`include "elink_constants.v"
module erx_clocks (/*AUTOARG*/
// Outputs
rx_lclk, rx_lclk_div4, erx_reset,
// Inputs
sys_reset, soft_reset, sys_clk, rx_clkin
);
`ifdef SIM
parameter RCW = 4; // reset counter width
`else
parameter RCW = 8; // reset counter width
`endif
//Frequency Settings (Mhz)
parameter FREQ_SYSCLK = 100;
parameter FREQ_RXCLK = 300;
parameter FREQ_IDELAY = 200;
parameter RXCLK_PHASE = 0; //270; //-90 deg rxclk phase shift
//VCO multiplers
parameter PLL_VCO_MULT = 4; //RX
//Input clock, reset, config interface
input sys_reset; // por reset (hw)
input soft_reset; // rx enable signal (sw)
//Main input clocks
input sys_clk; // always on input clk cclk/TX MMCM
input rx_clkin; // input clk for RX only PLL
//RX Clocks
output rx_lclk; // rx high speed clock for DDR IO
output rx_lclk_div4; // rx slow clock for logic
output erx_reset; // async reset for logic
//Don't touch these! (derived parameters)
localparam real RXCLK_PERIOD = 1000.000000/FREQ_RXCLK;
localparam integer IREF_DIVIDE = PLL_VCO_MULT*FREQ_RXCLK/FREQ_IDELAY;
localparam integer RXCLK_DIVIDE = PLL_VCO_MULT; //1:1
//############
//# WIRES
//############
//Idelay controller
wire idelay_reset;
wire idelay_ready; //ignore this?
wire idelay_ref_clk;
//pll outputs
wire rx_lclk_pll;
wire rx_lclk_div4_pll;
wire idelay_ref_clk_pll;
//PLL
wire rx_lclk_fb_in;
wire rx_lclk_fb_out;
//###########################
// RESET STATE MACHINE
//###########################
reg [RCW:0] reset_counter = 'b0; //works b/c of free running counter!
reg heartbeat;
reg pll_locked_reg;
reg pll_locked_sync;
reg [2:0] reset_state;
wire pll_reset;
//wrap around counter that generates a 1 cycle heartbeat
//free running counter...
always @ (posedge sys_clk)
begin
reset_counter[RCW-1:0] <= reset_counter[RCW-1:0]+1'b1;
heartbeat <= ~(|reset_counter[RCW-1:0]);
end
//two clock synchronizer
always @ (posedge sys_clk)
begin
pll_locked_reg <= pll_locked;
pll_locked_sync <= pll_locked_reg;
end
`define RESET_ALL 3'b000
`define START_PLL 3'b001
`define ACTIVE 3'b010
//Reset sequence state machine
always @ (posedge sys_clk or posedge sys_reset)
if(sys_reset)
reset_state[2:0] <= `RESET_ALL;
else if(heartbeat)
case(reset_state[2:0])
`RESET_ALL :
if(~soft_reset)
reset_state[2:0] <= `START_PLL;
`START_PLL :
if(pll_locked_sync & idelay_ready)
reset_state[2:0] <= `ACTIVE;
`ACTIVE:
if(soft_reset)
reset_state[2:0] <= `RESET_ALL; //stay there until next reset
endcase // case (reset_state[2:0])
//reset PLL during 'reset' and during quiet time around reset edge
assign pll_reset = (reset_state[2:0]==`RESET_ALL);
assign idelay_reset = (reset_state[2:0]==`RESET_ALL);
//asynch rx reset
assign erx_reset = (reset_state[2:0]!=`ACTIVE);
`ifdef TARGET_XILINX
//###########################
// PLL RX
//###########################
PLLE2_ADV
#(
.BANDWIDTH("OPTIMIZED"),
.CLKFBOUT_MULT(PLL_VCO_MULT),
.CLKFBOUT_PHASE(0.0),
.CLKIN1_PERIOD(RXCLK_PERIOD),
.CLKOUT0_DIVIDE(128),
.CLKOUT1_DIVIDE(128),
.CLKOUT2_DIVIDE(128),
.CLKOUT3_DIVIDE(IREF_DIVIDE), // idelay ref clk
.CLKOUT4_DIVIDE(RXCLK_DIVIDE), // rx_lclk
.CLKOUT5_DIVIDE(RXCLK_DIVIDE*4), // rx_lclk_div4
.CLKOUT0_DUTY_CYCLE(0.5),
.CLKOUT1_DUTY_CYCLE(0.5),
.CLKOUT2_DUTY_CYCLE(0.5),
.CLKOUT3_DUTY_CYCLE(0.5),
.CLKOUT4_DUTY_CYCLE(0.5),
.CLKOUT5_DUTY_CYCLE(0.5),
.CLKOUT0_PHASE(0.0),
.CLKOUT1_PHASE(0.0),
.CLKOUT2_PHASE(0.0),
.CLKOUT3_PHASE(0.0),
.CLKOUT4_PHASE(RXCLK_PHASE),
.CLKOUT5_PHASE(RXCLK_PHASE/4),
.DIVCLK_DIVIDE(1.0),
.REF_JITTER1(0.01),
.STARTUP_WAIT("FALSE")
) pll_rx
(
.CLKOUT0(),
.CLKOUT1(),
.CLKOUT2(),
.CLKOUT3(idelay_ref_clk_pll),
.CLKOUT4(rx_lclk_pll),
.CLKOUT5(rx_lclk_div4_pll),
.PWRDWN(1'b0),
.RST(pll_reset),
.CLKFBIN(rx_lclk_fb_in),
.CLKFBOUT(rx_lclk_fb_out),
.CLKIN1(rx_clkin),
.CLKIN2(1'b0),
.CLKINSEL(1'b1),
.DADDR(7'b0),
.DCLK(1'b0),
.DEN(1'b0),
.DI(16'b0),
.DWE(1'b0),
.DRDY(),
.DO(),
.LOCKED(pll_locked)
);
//Clock network
BUFG rx_lclk_bufg_i (.I(rx_lclk_pll), .O(rx_lclk)); //300Mhz
BUFG rx_lclk_div4_bufg_i (.I(rx_lclk_div4_pll), .O(rx_lclk_div4)); //75 MHz (300/4)
BUFG idelay_ref_bufg_i (.I(idelay_ref_clk_pll), .O(idelay_ref_clk));//idelay ctrl clock
//Feedback buffers
BUFG lclk_fb_bufg_i0(.I(rx_lclk_fb_in), .O(rx_lclk_fb_out)); //feedback
//###########################
// Idelay controller
//###########################
(* IODELAY_GROUP = "IDELAY_GROUP" *) // Group name for IDELAYCTRL
IDELAYCTRL idelayctrl_inst
(
.RDY(idelay_ready), // check ready flag in reset sequence?
.REFCLK(idelay_ref_clk),//200MHz clk (78ps tap delay)
.RST(idelay_reset));
`endif // `ifdef TARGET_XILINX
endmodule // eclocks
// Local Variables:
// verilog-library-directories:("." "../../common/hdl")
// End:
/*
Copyright (C) 2015 Adapteva, Inc.
Contributed by Andreas Olofsson <andreas@adapteva.com>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.This program is distributed in the hope
that it will be useful,but WITHOUT ANY WARRANTY without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details. You should have received a copy
of the GNU General Public License along with this program (see the file
COPYING). If not, see <http://www.gnu.org/licenses/>.
*/

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elink/hdl/etx_clocks.v Normal file
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`include "elink_constants.v"
module etx_clocks (/*AUTOARG*/
// Outputs
tx_lclk, tx_lclk90, tx_lclk_div4, cclk_p, cclk_n, etx_reset,
etx_io_reset, chip_resetb,
// Inputs
sys_reset, soft_reset, sys_clk
);
`ifdef SIM
parameter RCW = 4; // reset counter width
`else
parameter RCW = 8; // reset counter width
`endif
//Frequency Settings (Mhz)
parameter FREQ_SYSCLK = 100;
parameter FREQ_TXCLK = 300;
parameter FREQ_CCLK = 600;
parameter TXCLK_PHASE = 90; //txclk phase shift
//Don't touch these! (derived parameters)
localparam real SYSCLK_PERIOD = 1000.000000/FREQ_SYSCLK;
localparam integer TXCLK_DIVIDE = MMCM_VCO_MULT*FREQ_SYSCLK/FREQ_TXCLK;
localparam integer CCLK_DIVIDE = MMCM_VCO_MULT*FREQ_SYSCLK/FREQ_CCLK;
//VCO multiplers
parameter MMCM_VCO_MULT = 12; //TX + CCLK
//Input clock, reset, config interface
input sys_reset; // por reset (hw)
input soft_reset; // rx enable signal (sw)
//Main input clocks
input sys_clk; // always on input clk cclk/TX MMCM
//TX Clocks
output tx_lclk; // tx clock for DDR IO
output tx_lclk90; // tx output clock shifted by 90 degrees
output tx_lclk_div4; // tx slow clock for logic
//Epiphany "free running" clock
output cclk_p, cclk_n;
//Reset
output etx_reset; // reset for tx core logic
output etx_io_reset; // io reset (synced to high speed clock)
output chip_resetb; // reset fpr Epiphany chip
//############
//# WIRES
//############
//CCLK
wire cclk_reset;
wire cclk_mmcm;
wire cclk_bufio;
wire cclk_oddr;
//TX
wire tx_lclk_mmcm;
wire tx_lclk90_mmcm;
wire tx_lckl_div4_mmcm;
//MMCM & PLL
wire cclk_fb_in;
wire cclk_fb_out;
wire lclk_fb_i;
wire pll_reset;
wire mmcm_locked;
reg mmcm_locked_reg;
reg mmcm_locked_sync;
wire lclk_locked;
//###########################
// RESET STATE MACHINE
//###########################
reg [RCW:0] reset_counter = 'b0; //works b/c of free running counter!
reg heartbeat;
reg [2:0] reset_state;
reg [1:0] reset_pipe_lclkb;
reg [1:0] reset_pipe_lclk_div4b;
//wrap around counter that generates a 1 cycle heartbeat
//free running counter...
always @ (posedge sys_clk)
begin
reset_counter[RCW-1:0] <= reset_counter[RCW-1:0]+1'b1;
heartbeat <= ~(|reset_counter[RCW-1:0]);
end
//two clock synchronizer
always @ (posedge sys_clk)
begin
mmcm_locked_reg <= mmcm_locked;
mmcm_locked_sync <= mmcm_locked_reg;
end
`define RESET_ALL 3'b000
`define START_CCLK 3'b001
`define STOP_CCLK 3'b010
`define DEASSERT_RESET 3'b011
`define HOLD_IT 3'b100 //???
`define ACTIVE 3'b101
//Reset sequence state machine
always @ (posedge sys_clk or posedge sys_reset)
if(sys_reset)
reset_state[2:0] <= `RESET_ALL;
else if(heartbeat)
case(reset_state[2:0])
`RESET_ALL :
if(~soft_reset)
reset_state[2:0] <= `START_CCLK;
`START_CCLK :
if(mmcm_locked_sync)
reset_state[2:0] <= `STOP_CCLK;
`STOP_CCLK :
reset_state[2:0] <= `DEASSERT_RESET;
`DEASSERT_RESET :
reset_state[2:0] <= `HOLD_IT;
`HOLD_IT :
if(mmcm_locked_sync)
reset_state[2:0] <= `ACTIVE;
`ACTIVE:
if(soft_reset)
reset_state[2:0] <= `RESET_ALL; //stay there until nex reset
endcase // case (reset_state[2:0])
//reset mmcm (async)
assign mmcm_reset = (reset_state[2:0]==`RESET_ALL) |
(reset_state[2:0]==`STOP_CCLK) |
(reset_state[2:0]==`DEASSERT_RESET) |
sys_reset
;
//reset chip (active low)
assign chip_resetb = (reset_state[2:0]==`DEASSERT_RESET) |
(reset_state[2:0]==`HOLD_IT) |
(reset_state[2:0]==`ACTIVE);
//reset the elink
wire tx_reset = sys_reset |
(reset_state[2:0] != `ACTIVE);
//#############################
//#RESET SYNC
//#############################
//async assert
//sync deassert
//lclk sync
always @ (posedge tx_lclk or posedge tx_reset)
if(tx_reset)
reset_pipe_lclkb[1:0] <= 2'b00;
else
reset_pipe_lclkb[1:0] <= {reset_pipe_lclkb[0], 1'b1};
assign etx_io_reset = ~reset_pipe_lclkb[1];
//lclkdiv4 sync
always @ (posedge tx_lclk_div4 or posedge tx_reset)
if(tx_reset)
reset_pipe_lclk_div4b[1:0] <= 2'b00;
else
reset_pipe_lclk_div4b[1:0] <= {reset_pipe_lclk_div4b[0],1'b1};
assign etx_reset = ~reset_pipe_lclk_div4b[1];
`ifdef TARGET_XILINX
//###########################
// MMCM FOR TXCLK + CCLK
//###########################
MMCME2_ADV
#(
.BANDWIDTH("OPTIMIZED"),
.CLKFBOUT_MULT_F(MMCM_VCO_MULT),
.CLKFBOUT_PHASE(0.0),
.CLKIN1_PERIOD(SYSCLK_PERIOD),
.CLKOUT0_DIVIDE_F(CCLK_DIVIDE), //cclk_c
.CLKOUT1_DIVIDE(TXCLK_DIVIDE), //tx_lclk
.CLKOUT2_DIVIDE(TXCLK_DIVIDE), //tx_lclk90
.CLKOUT3_DIVIDE(TXCLK_DIVIDE*4), //tx_lclk_div4
.CLKOUT4_DIVIDE(128), //N/A
.CLKOUT5_DIVIDE(128), //N/A
.CLKOUT6_DIVIDE(128), //N/A
.CLKOUT0_DUTY_CYCLE(0.5),
.CLKOUT1_DUTY_CYCLE(0.5),
.CLKOUT2_DUTY_CYCLE(0.5),
.CLKOUT3_DUTY_CYCLE(0.5),
.CLKOUT4_DUTY_CYCLE(0.5),
.CLKOUT5_DUTY_CYCLE(0.5),
.CLKOUT6_DUTY_CYCLE(0.5),
.CLKOUT0_PHASE(0.0),
.CLKOUT1_PHASE(0.0),
.CLKOUT2_PHASE(TXCLK_PHASE),
.CLKOUT3_PHASE(0.0),
.CLKOUT4_PHASE(0.0),
.CLKOUT5_PHASE(0.0),
.CLKOUT6_PHASE(0.0),
.DIVCLK_DIVIDE(1.0),
.REF_JITTER1(0.01),
.STARTUP_WAIT("FALSE")
) mmcm_cclk
(
.CLKOUT0(cclk_mmcm),
.CLKOUT0B(),
.CLKOUT1(tx_lclk_mmcm),
.CLKOUT1B(),
.CLKOUT2(tx_lclk90_mmcm),
.CLKOUT2B(),
.CLKOUT3(tx_lclk_div4_mmcm),
.CLKOUT3B(),
.CLKOUT4(),
.CLKOUT5(),
.CLKOUT6(),
.PWRDWN(1'b0),
.RST(mmcm_reset), //reset
.CLKFBIN(cclk_fb_in),
.CLKFBOUT(cclk_fb_out), //feedback clock
.CLKIN1(sys_clk), //input clock
.CLKIN2(1'b0),
.CLKINSEL(1'b1),
.DADDR(7'b0),
.DCLK(1'b0),
.DEN(1'b0),
.DI(16'b0),
.DWE(1'b0),
.DRDY(),
.DO(),
.LOCKED(mmcm_locked), //locked indicator
.PSCLK(1'b0),
.PSEN(1'b0),
.PSDONE(),
.PSINCDEC(1'b0),
.CLKFBSTOPPED(),
.CLKINSTOPPED()
);
//Feedback buffer
BUFG cclk_fb_bufg_i(.I(cclk_fb_out), .O(cclk_fb_in));
//Tx clock buffers
BUFG tx_lclk_bufg_i (.I(tx_lclk_mmcm), .O(tx_lclk));
BUFG tx_lclk_div4_bufg_i (.I(tx_lclk_div4_mmcm), .O(tx_lclk_div4));
BUFG tx_lclk90_bufg_i (.I(tx_lclk90_mmcm), .O(tx_lclk90));
//###########################
// CCLK
//###########################
//CCLK bufio
BUFIO bufio_cclk(.O(cclk_bufio), .I(cclk_mmcm));
//CCLK oddr
ODDR #(.DDR_CLK_EDGE ("SAME_EDGE"), .SRTYPE("ASYNC"))
oddr_lclk (
.Q (cclk_oddr),
.C (cclk_bufio),
.CE (1'b1),
.D1 (1'b1),
.D2 (1'b0),
.R (sys_reset),
.S (1'b0));
//CCLK differential buffer
OBUFDS cclk_obuf (.O (cclk_p),
.OB (cclk_n),
.I (cclk_oddr)
);
`else // !`ifdef TARGET_XILINX
assign cclk_p = sys_clk;
assign cclk_n = sys_clk;
assign tx_lclk = sys_clk;
assign tx_lclk_div4 = sys_clk;
assign tx_lclk90 = sys_clk;
x
`endif // `ifdef TARGET_XILINX
endmodule // eclocks
// Local Variables:
// verilog-library-directories:("." "../../common/hdl")
// End:
/*
Copyright (C) 2015 Adapteva, Inc.
Contributed by Andreas Olofsson <andreas@adapteva.com>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.This program is distributed in the hope
that it will be useful,but WITHOUT ANY WARRANTY without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details. You should have received a copy
of the GNU General Public License along with this program (see the file
COPYING). If not, see <http://www.gnu.org/licenses/>.
*/