continue on status infrastructure (f97c6e28) · Commits · Elphel / x393

.gitignore

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	@@ -5,4 +5,5 @@ simulation/*
	ise_*		ise_*
	attic/*		attic/*
	IVERILOG_INCLUDE.v		IVERILOG_INCLUDE.v
	eddr3.prj		x393.prj
	No newline at end of file		DEBUG_VDT

status_generate.v

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			/*******************************************************************************
			* Module: status_generate
			* Date:2015-01-14
			* Author: andrey
			* Description: generate byte-serial status data
			*
			* Copyright (c) 2015 <set up in Preferences-Verilog/VHDL Editor-Templates> .
			* status_generate.v 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.
			*
			* status_generate.v 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. If not, see <http://www.gnu.org/licenses/> .
			*******************************************************************************/
			`timescale 1ns/1ps
			// mode bits: 0 disable status generation, 1 single status request, 2 - auto status, keep specified seq number, 3 - auto, inc sequence number
			module status_generate #(
			parameter STATUS_REG_ADDR=7, // status register address to direct data to
			parameter PAYLOAD_BITS=26 //6 // >=2! (2..26)
			)(
			input rst,
			input clk,
			input we, // command strobe
			input [7:0] wd, // command data - 6 bits of sequence and 2 mode bits
			input [PAYLOAD_BITS-1:0] status, // parallel status data to be sent out
			output [7:0] ad, // byte-wide address/data
			output rq, // request to send downstream (last byte with rq==0)
			input start // acknowledge of address (first byte) from downsteram
			);
			/*
			Some tools may not like {0{}}, and currently VEditor makes it UNDEFINED->32 bits
			assigning to constant?a:b now works if constant has defined value, i.e. if constant=1 b is ignored
			*/
			localparam NUM_BYTES=(PAYLOAD_BITS+21)>>3;
			localparam ALIGNED_STATUS_WIDTH=((NUM_BYTES-2)<<3)+2; // 2 ->2,
			// ugly solution to avoid warnings in unused branch
			localparam ALIGNED_STATUS_BIT_2=(ALIGNED_STATUS_WIDTH>2)?2:0;
			reg [1:0] mode;
			reg [5:0] seq;
			reg [PAYLOAD_BITS-1:0] status_r; // "frozen" status to be sent;
			reg status_changed_r; // not reset if status changes back to original
			reg cmd_pend;
			reg [((NUM_BYTES-1)<<3)-1:0] data;
			wire snd_rest;
			wire need_to_send;
			wire [ALIGNED_STATUS_WIDTH-1:0] aligned_status;

			reg [NUM_BYTES-2:0] rq_r;

			assign aligned_status=(ALIGNED_STATUS_WIDTH==PAYLOAD_BITS)?status:{{(ALIGNED_STATUS_WIDTH-PAYLOAD_BITS){1'b0}},status};
			assign ad=data[7:0];
			assign need_to_send=cmd_pend \|\| (mode[1] && status_changed_r); // latency
			assign rq=rq_r[0]; // NUM_BYTES-2];
			assign snd_rest=rq_r[0] && !rq_r[NUM_BYTES-2];
			always @ (posedge rst or posedge clk) begin

			if (rst) status_changed_r <= 0;
			else status_changed_r <= (status_changed_r && !start) \|\| (status_r != status);

			if (rst) mode <= 0;
			else if (we) mode <= wd[7:6];

			if (rst) seq <= 0;
			else if (we) seq <= wd[5:0];
			else if ((mode==3) && start) seq <= seq+1;

			if (rst) cmd_pend <= 0;
			else if (we) cmd_pend <= 1;
			else if (start) cmd_pend <= 0;

			if (rst) status_r<=0;
			else if (start) status_r<=status;

			if (rst) data <= STATUS_REG_ADDR;
			else if (start) data <= (NUM_BYTES>2)?
			{aligned_status[ALIGNED_STATUS_WIDTH-1:ALIGNED_STATUS_BIT_2],seq,status[1:0]}:
			{seq,status[1:0]};
			else if ((NUM_BYTES>2) && snd_rest) data <= data >> 8; // never happens with 2-byte packet
			else data <= STATUS_REG_ADDR;

			if (rst) rq_r <= 0;
			else if (need_to_send && !rq_r[0]) rq_r <= {NUM_BYTES-1{1'b1}};
			else if (start \|\| ((NUM_BYTES>2) && !rq_r[NUM_BYTES-2])) rq_r <= rq_r >> 1;
			end
			endmodule

status_read.v

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			/*******************************************************************************
			* Module: status_read
			* Date:2015-01-14
			* Author: andrey
			* Description: Receives status read data (low bandwidth) from multiple
			* subsystems byte-serial, stores in axi-addressable memory
			* 8-bita ddress is received from the source module,
			* as well as another (optional) byte of sequence number (set in write command)
			* Sequence number (received first afther the address) is stored as a high byte,
			* lower bytes are the actual payload, starting from lower byte (not all 3 are
			* required. Single-bit responsen can be combined in the same byte with the
			* sequence number to use just 2-byte packets?
			* TODO: add interrupt capabilities
			*
			* Copyright (c) 2015 <set up in Preferences-Verilog/VHDL Editor-Templates> .
			* status_read.v 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.
			*
			* status_read.v 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. If not, see <http://www.gnu.org/licenses/> .
			*******************************************************************************/
			`timescale 1ns/1ps

			module status_read#(
			parameter STATUS_ADDR = 'h1400, // AXI write address of status read registers
			parameter STATUS_ADDR_MASK = 'h1400, // AXI write address of status registers
			parameter AXI_RD_ADDR_BITS = 13,
			parameter integer DATA_DEPTH= 8 // 256 cells, maybe just 16..64 are enough?
			)(
			input rst,
			input clk,
			input [AXI_RD_ADDR_BITS-1:0] axi_pre_addr, // status read address, 1 cycle ahead of read data
			input pre_stb, // read data request, with axi_pre_addr
			output reg [31:0] axi_status_rdata, // read data, 1 cycle latency from the address/stb
			output reg data_valid, // read data valid, 1 cycle latency from pre_stb, decoded address
			input [7:0] ad, // byte-serial status data from the sources
			input rq, // request from sources to transfer status data
			output start // acknowledge receiving of first byte (address), currently always ready
			);
			localparam integer DATA_2DEPTH=(1<<DATA_DEPTH)-1;
			reg [31:0] ram [0:DATA_2DEPTH];
			reg [DATA_DEPTH-1:0] waddr;
			wire [DATA_DEPTH-1:0] raddr;
			reg we;
			wire re;
			reg [31: 0] wdata;
			reg rq_r;
			reg [3:0] dstb;

			assign re= pre_stb && (((axi_pre_addr ^ STATUS_ADDR) & STATUS_ADDR_MASK) == 0);
			assign raddr=axi_pre_addr[DATA_DEPTH-1:0];
			assign start=rq && !rq_r;

			always @ (posedge rst or posedge clk) begin
			if (rst) data_valid <= 0;
			else data_valid <= re;

			if (rst) rq_r <= 0;
			else rq_r <= rq;

			if (rst) dstb <= 0;
			else if (!rq) dstb <= 0;
			else dstb <= {dstb[2:0],~rq_r};
			// byte 0 - address
			if (rst) waddr <= 0;
			else if (start) waddr <= ad[DATA_DEPTH-1:0];

			// byte 1 - 2 payload bits and sequence number
			// 6 bits of the sequence number will go to bits 26.. 31
			// 2 bits (24,25) are payload status
			if (rst) wdata[31:24] <= 0;
			else if (start) wdata[31:24] <= 0;
			else if (dstb[0]) wdata[31:24] <= ad;

			// byte 2 - payload bits 0..7
			if (rst) wdata[ 7: 0] <= 0;
			else if (start) wdata[ 7: 0] <= 0;
			else if (dstb[1]) wdata[ 7: 0] <= ad;

			// byte 3 - payload bits 8..15
			if (rst) wdata[15: 8] <= 0;
			else if (start) wdata[15: 8] <= 0;
			else if (dstb[2]) wdata[15: 8] <= ad;

			// byte 4 - payload bits 16..23
			if (rst) wdata[23:16] <= 0;
			else if (start) wdata[23:16] <= 0;
			else if (dstb[3]) wdata[23:16] <= ad;

			if (rst) we <= 0;
			else we <= !rq && rq_r;
			end

			always @ (posedge clk) begin
			if (we) ram[waddr] <= wdata; // shifted data here
			if (re) axi_status_rdata<= ram[raddr];
			end



			endmodule

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