CAN总线控制器IP核的代码分析
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include "timescale.v"
// synopsys translate_on
`include "can_defines.v"
module can_top
(
`ifdef CAN_WISHBONE_IF
wb_clk_i,
wb_rst_i,
wb_dat_i,
wb_dat_o,
wb_cyc_i,
wb_stb_i,
wb_we_i,
wb_adr_i,
wb_ack_o,
`else
rst_i,
ale_i,
rd_i,
wr_i,
port_0_io,
`endif
cs_can_i,
clk_i,
rx_i,
tx_o,
irq_on,
clkout_o
);
parameter Tp = 1;
`ifdef CAN_WISHBONE_IF
input wb_clk_i;
input wb_rst_i;
input [7:0] wb_dat_i;
output [7:0] wb_dat_o;
input wb_cyc_i;
input wb_stb_i;
input wb_we_i;
input [7:0] wb_adr_i;
output wb_ack_o;
reg wb_ack_o;
reg cs_sync1;
reg cs_sync2;
reg cs_sync3;
reg cs_ack1;
reg cs_ack2;
reg cs_ack3;
reg cs_sync_rst1;
reg cs_sync_rst2;
`else
input rst_i;
input ale_i;
input rd_i;
input wr_i;
inout [7:0] port_0_io;
reg [7:0] addr_latched;
reg wr_i_q;
reg rd_i_q;
`endif
input cs_can_i;
input clk_i;
input rx_i;
output tx_o;
output irq_on;
output clkout_o;
reg data_out_fifo_selected;
wire irq_o;
wire [7:0] data_out_fifo;
wire [7:0] data_out_regs;
/* Mode register */
wire reset_mode;
wire listen_only_mode;
wire acceptance_filter_mode;
wire self_test_mode;
/* Command register */
wire release_buffer;
wire tx_request;
wire abort_tx;
wire self_rx_request;
wire single_shot_transmission;
/* Arbitration Lost Capture Register */
wire read_arbitration_lost_capture_reg;
/* Error Code Capture Register */
wire read_error_code_capture_reg;
wire [7:0] error_capture_code;
/* Bus Timing 0 register */
wire [5:0] baud_r_presc;
wire [1:0] sync_jump_width;
/* Bus Timing 1 register */
wire [3:0] time_segment1;
wire [2:0] time_segment2;
wire triple_sampling;
/* Error Warning Limit register */
wire [7:0] error_warning_limit;
/* Rx Error Counter register */
wire we_rx_err_cnt;
/* Tx Error Counter register */
wire we_tx_err_cnt;
/* Clock Divider register */
wire extended_mode;
/* This section is for BASIC and EXTENDED mode */
/* Acceptance code register */
wire [7:0] acceptance_code_0;
/* Acceptance mask register */
wire [7:0] acceptance_mask_0;
/* End: This section is for BASIC and EXTENDED mode */
/* This section is for EXTENDED mode */
/* Acceptance code register */
wire [7:0] acceptance_code_1;
wire [7:0] acceptance_code_2;
wire [7:0] acceptance_code_3;
/* Acceptance mask register */
wire [7:0] acceptance_mask_1;
wire [7:0] acceptance_mask_2;
wire [7:0] acceptance_mask_3;
/* End: This section is for EXTENDED mode */
/* Tx data registers. Holding identifier (basic mode), tx frame information (extended mode) and data */
wire [7:0] tx_data_0;
wire [7:0] tx_data_1;
wire [7:0] tx_data_2;
wire [7:0] tx_data_3;
wire [7:0] tx_data_4;
wire [7:0] tx_data_5;
wire [7:0] tx_data_6;
wire [7:0] tx_data_7;
wire [7:0] tx_data_8;
wire [7:0] tx_data_9;
wire [7:0] tx_data_10;
wire [7:0] tx_data_11;
wire [7:0] tx_data_12;
/* End: Tx data registers */
wire cs;
/* Output signals from can_btl module */
wire clk_en;
wire sample_point;
wire sampled_bit;
wire sampled_bit_q;
wire tx_point;
wire hard_sync;
wire resync;
/* output from can_bsp module */
wire rx_idle;
wire transmitting;
wire last_bit_of_inter;
wire set_reset_mode;
wire node_bus_off;
wire error_status;
wire [7:0] rx_err_cnt;
wire [7:0] tx_err_cnt;
wire rx_err_cnt_dummy; // The MSB is not displayed. It is just used for easier calculation (no counter overflow).
wire tx_err_cnt_dummy; // The MSB is not displayed. It is just used for easier calculation (no counter overflow).
wire transmit_status;
wire receive_status;
wire tx_successful;
wire need_to_tx;
wire overrun;
wire info_empty;
wire set_bus_error_irq;
wire set_arbitration_lost_irq;
wire [4:0] arbitration_lost_capture;
wire node_error_passive;
wire node_error_active;
wire [6:0] rx_message_counter;
wire tx_out;
wire tx_oen;
wire rst;
wire we;
wire [7:0] addr;
wire [7:0] data_in;
reg [7:0] data_out;
/* Connecting can_registers module */
can_registers i_can_registers
(
.clk(clk_i),
.rst(rst),
.cs(cs),
.we(we),
.addr(addr),
.data_in(data_in),
.data_out(data_out_regs),
.irq(irq_o),
.sample_point(sample_point),
.transmitting(transmitting),
.set_reset_mode(set_reset_mode),
.node_bus_off(node_bus_off),
.error_status(error_status),
.rx_err_cnt(rx_err_cnt),
.tx_err_cnt(tx_err_cnt),
.transmit_status(transmit_status),
.receive_status(receive_status),
.tx_successful(tx_successful),
.need_to_tx(need_to_tx),
.overrun(overrun),
.info_empty(info_empty),
.set_bus_error_irq(set_bus_error_irq),
.set_arbitration_lost_irq(set_arbitration_lost_irq),
.arbitration_lost_capture(arbitration_lost_capture),
.node_error_passive(node_error_passive),
.node_error_active(node_error_active),
.rx_message_counter(rx_message_counter),
/* Mode register */
.reset_mode(reset_mode),
.listen_only_mode(listen_only_mode),
.acceptance_filter_mode(acceptance_filter_mode),
.self_test_mode(self_test_mode),
/* Command register */
.clear_data_overrun(),
.release_buffer(release_buffer),
.abort_tx(abort_tx),
.tx_request(tx_request),
.self_rx_request(self_rx_request),
.single_shot_transmission(single_shot_transmission),
/* Arbitration Lost Capture Register */
.read_arbitration_lost_capture_reg(read_arbitration_lost_capture_reg),
/* Error Code Capture Register */
.read_error_code_capture_reg(read_error_code_capture_reg),
.error_capture_code(error_capture_code),
/* Bus Timing 0 register */
.baud_r_presc(baud_r_presc),
.sync_jump_width(sync_jump_width),
/* Bus Timing 1 register */
.time_segment1(time_segment1),
.time_segment2(time_segment2),
.triple_sampling(triple_sampling),
/* Error Warning Limit register */
.error_warning_limit(error_warning_limit),
/* Rx Error Counter register */
.we_rx_err_cnt(we_rx_err_cnt),
/* Tx Error Counter register */
.we_tx_err_cnt(we_tx_err_cnt),
/* Clock Divider register */
.extended_mode(extended_mode),
.clkout(clkout_o),
/* This section is for BASIC and EXTENDED mode */
/* Acceptance code register */
.acceptance_code_0(acceptance_code_0),
/* Acceptance mask register */
.acceptance_mask_0(acceptance_mask_0),
/* End: This section is for BASIC and EXTENDED mode */
/* This section is for EXTENDED mode */
/* Acceptance code register */
.acceptance_code_1(acceptance_code_1),
.acceptance_code_2(acceptance_code_2),
.acceptance_code_3(acceptance_code_3),
/* Acceptance mask register */
.acceptance_mask_1(acceptance_mask_1),
.acceptance_mask_2(acceptance_mask_2),
.acceptance_mask_3(acceptance_mask_3),
/* End: This section is for EXTENDED mode */
/* Tx data registers. Holding identifier (basic mode), tx frame information (extended mode) and data */
.tx_data_0(tx_data_0),
.tx_data_1(tx_data_1),
.tx_data_2(tx_data_2),
.tx_data_3(tx_data_3),
.tx_data_4(tx_data_4),
.tx_data_5(tx_data_5),
.tx_data_6(tx_data_6),
.tx_data_7(tx_data_7),
.tx_data_8(tx_data_8),
.tx_data_9(tx_data_9),
.tx_data_10(tx_data_10),
.tx_data_11(tx_data_11),
.tx_data_12(tx_data_12)
/* End: Tx data registers */
);
assign irq_on = ~irq_o;
/* Connecting can_btl module */
can_btl i_can_btl
(
.clk(clk_i),
.rst(rst),
.rx(rx_i),
/* Mode register */
.reset_mode(reset_mode),
/* Bus Timing 0 register */
.baud_r_presc(baud_r_presc),
.sync_jump_width(sync_jump_width),
/* Bus Timing 1 register */
.time_segment1(time_segment1),
.time_segment2(time_segment2),
.triple_sampling(triple_sampling),
/* Output signals from this module */
.clk_en(clk_en),
.sample_point(sample_point),
.sampled_bit(sampled_bit),
.sampled_bit_q(sampled_bit_q),
.tx_point(tx_point),
.hard_sync(hard_sync),
.resync(resync),
/* output from can_bsp module */
.rx_idle(rx_idle),
.transmitting(transmitting),
.last_bit_of_inter(last_bit_of_inter)
);
can_bsp i_can_bsp
(
.clk(clk_i),
.rst(rst),
/* From btl module */
.sample_point(sample_point),
.sampled_bit(sampled_bit),
.sampled_bit_q(sampled_bit_q),
.tx_point(tx_point),
.hard_sync(hard_sync),
.addr(addr),
.data_in(data_in),
.data_out(data_out_fifo),
.fifo_selected(data_out_fifo_selected),
/* Mode register */
.reset_mode(reset_mode),
.listen_only_mode(listen_only_mode),
.acceptance_filter_mode(acceptance_filter_mode),
.self_test_mode(self_test_mode),
/* Command register */
.release_buffer(release_buffer),
.tx_request(tx_request),
.abort_tx(abort_tx),
.self_rx_request(self_rx_request),
.single_shot_transmission(single_shot_transmission),
/* Arbitration Lost Capture Register */
.read_arbitration_lost_capture_reg(read_arbitration_lost_capture_reg),
/* Error Code Capture Register */
.read_error_code_capture_reg(read_error_code_capture_reg),
.error_capture_code(error_capture_code),
/* Error Warning Limit register */
.error_warning_limit(error_warning_limit),
/* Rx Error Counter register */
.we_rx_err_cnt(we_rx_err_cnt),
/* Tx Error Counter register */
.we_tx_err_cnt(we_tx_err_cnt),
/* Clock Divider register */
.extended_mode(extended_mode),
/* output from can_bsp module */
.rx_idle(rx_idle),
.transmitting(transmitting),
.last_bit_of_inter(last_bit_of_inter),
.set_reset_mode(set_reset_mode),
.node_bus_off(node_bus_off),
.error_status(error_status),
.rx_err_cnt({rx_err_cnt_dummy, rx_err_cnt[7:0]}), // The MSB is not displayed. It is just used for easier calculation (no counter overflow).
.tx_err_cnt({tx_err_cnt_dummy, tx_err_cnt[7:0]}), // The MSB is not displayed. It is just used for easier calculation (no counter overflow).
.transmit_status(transmit_status),
.receive_status(receive_status),
.tx_successful(tx_successful),
.need_to_tx(need_to_tx),
.overrun(overrun),
.info_empty(info_empty),
.set_bus_error_irq(set_bus_error_irq),
.set_arbitration_lost_irq(set_arbitration_lost_irq),
.arbitration_lost_capture(arbitration_lost_capture),
.node_error_passive(node_error_passive),
.node_error_active(node_error_active),
.rx_message_counter(rx_message_counter),
/* This section is for BASIC and EXTENDED mode */
/* Acceptance code register */
.acceptance_code_0(acceptance_code_0),
/* Acceptance mask register */
.acceptance_mask_0(acceptance_mask_0),
/* End: This section is for BASIC and EXTENDED mode */
/* This section is for EXTENDED mode */
/* Acceptance code register */
.acceptance_code_1(acceptance_code_1),
.acceptance_code_2(acceptance_code_2),
.acceptance_code_3(acceptance_code_3),
/* Acceptance mask register */
.acceptance_mask_1(acceptance_mask_1),
.acceptance_mask_2(acceptance_mask_2),
.acceptance_mask_3(acceptance_mask_3),
/* End: This section is for EXTENDED mode */
/* Tx data registers. Holding identifier (basic mode), tx frame information (extended mode) and data */
.tx_data_0(tx_data_0),
.tx_data_1(tx_data_1),
.tx_data_2(tx_data_2),
.tx_data_3(tx_data_3),
.tx_data_4(tx_data_4),
.tx_data_5(tx_data_5),
.tx_data_6(tx_data_6),
.tx_data_7(tx_data_7),
.tx_data_8(tx_data_8),
.tx_data_9(tx_data_9),
.tx_data_10(tx_data_10),
.tx_data_11(tx_data_11),
.tx_data_12(tx_data_12),
/* End: Tx data registers */
/* Tx signal */
.tx(tx_out),
.tx_oen(tx_oen)
);
assign tx_o = tx_oen? 1'bz : tx_out;
// Multiplexing wb_dat_o from registers and rx fifo
always @ (extended_mode or addr or reset_mode)
begin
if (extended_mode & (~reset_mode) & ((addr >= 8'd16) && (addr <= 8'd28)) | (~extended_mode) & ((addr >= 8'd20) && (addr <= 8'd29)))
data_out_fifo_selected <= 1'b1;
else
data_out_fifo_selected <= 1'b0;
end
always @ (posedge clk_i)
begin
// if (wb_cyc_i & (~wb_we_i))
if (cs & (~we))
begin
if (data_out_fifo_selected)
data_out <=#Tp data_out_fifo;
else
data_out <=#Tp data_out_regs;
end
end
`ifdef CAN_WISHBONE_IF
// Combining wb_cyc_i and wb_stb_i signals to cs signal. Than synchronizing to clk_i clock domain.
always @ (posedge clk_i or posedge rst)
begin
if (rst)
begin
cs_sync1 <= 1'b0;
cs_sync2 <= 1'b0;
cs_sync3 <= 1'b0;
cs_sync_rst1 <= 1'b0;
cs_sync_rst2 <= 1'b0;
end
else
begin
cs_sync1 <=#Tp wb_cyc_i & wb_stb_i & (~cs_sync_rst2) & cs_can_i;
cs_sync2 <=#Tp cs_sync1 & (~cs_sync_rst2);
cs_sync3 <=#Tp cs_sync2 & (~cs_sync_rst2);
cs_sync_rst1 <=#Tp cs_ack3;
cs_sync_rst2 <=#Tp cs_sync_rst1;
end
end
assign cs = cs_sync2 & (~cs_sync3);
always @ (posedge wb_clk_i)
begin
cs_ack1 <=#Tp cs_sync3;
cs_ack2 <=#Tp cs_ack1;
cs_ack3 <=#Tp cs_ack2;
end
// Generating acknowledge signal
always @ (posedge wb_clk_i)
begin
wb_ack_o <=#Tp (cs_ack2 & (~cs_ack3));
end
assign rst = wb_rst_i;
assign we = wb_we_i;
assign addr = wb_adr_i;
assign data_in = wb_dat_i;
assign wb_dat_o = data_out;
`else
// Latching address
always @ (negedge clk_i or posedge rst)
begin
if (rst)
addr_latched <= 8'h0;
else if (ale_i)
addr_latched <=#Tp port_0_io;
end
// Generating delayed wr_i and rd_i signals
always @ (posedge clk_i or posedge rst)
begin
if (rst)
begin
wr_i_q <= 1'b0;
rd_i_q <= 1'b0;
end
else
begin
wr_i_q <=#Tp wr_i;
rd_i_q <=#Tp rd_i;
end
end
assign cs = ((wr_i & (~wr_i_q)) | (rd_i & (~rd_i_q))) & cs_can_i;
assign rst = rst_i;
assign we = wr_i;
assign addr = addr_latched;
assign data_in = port_0_io;
assign port_0_io = (cs_can_i & rd_i)? data_out : 8'hz;
`endif
endmodule
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