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-rw-r--r--rtl/bus_master.sv63
1 files changed, 63 insertions, 0 deletions
diff --git a/rtl/bus_master.sv b/rtl/bus_master.sv
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+++ b/rtl/bus_master.sv
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+module bus_master
+(
+ input logic clk,
+ rst,
+
+ input logic[29:0] addr,
+ input logic start,
+ write,
+ output logic ready,
+ output logic[31:0] data_rd,
+ input logic[31:0] data_wr,
+
+ output logic[31:0] avl_address,
+ output logic avl_read,
+ avl_write,
+ input logic[31:0] avl_readdata,
+ output logic[31:0] avl_writedata,
+ input logic avl_waitrequest,
+ output logic[3:0] avl_byteenable
+);
+
+ enum {
+ IDLE,
+ WAIT
+ } state;
+
+ assign data_rd = avl_readdata;
+ assign avl_byteenable = 4'b1111; //TODO
+
+ always_comb
+ unique case(state)
+ IDLE: ready = 0;
+ WAIT: ready = !avl_waitrequest;
+ endcase
+
+ always_ff @(posedge clk) begin
+ unique case(state)
+ IDLE: begin
+ avl_read <= 0;
+ avl_write <= 0;
+ end
+
+ WAIT:
+ if(!start)
+ state <= IDLE;
+ endcase
+
+ if(!avl_waitrequest && start) begin
+ avl_address <= {addr, 2'b00};
+ avl_read <= ~write;
+ avl_write <= write;
+ avl_writedata <= data_wr;
+ state <= WAIT;
+ end
+ end
+
+ initial begin
+ state = IDLE;
+ avl_read = 0;
+ avl_write = 0;
+ end
+
+endmodule