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-rw-r--r--fpga/usrp2/control_lib/ram_wb_harvard.v86
1 files changed, 86 insertions, 0 deletions
diff --git a/fpga/usrp2/control_lib/ram_wb_harvard.v b/fpga/usrp2/control_lib/ram_wb_harvard.v
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+
+// Dual ported RAM for Harvard architecture processors
+// Does no forwarding
+// Addresses are byte-oriented, so botton 2 address bits are ignored. FIXME
+// AWIDTH of 13 gives 8K bytes. For Spartan 3, if the total RAM size is not a
+// multiple of 8K then BRAM space is wasted
+
+module ram_wb_harvard #(parameter AWIDTH=13)
+ (input wb_clk_i,
+ input wb_rst_i,
+
+ input [AWIDTH-1:0] iwb_adr_i,
+ input [31:0] iwb_dat_i,
+ output reg [31:0] iwb_dat_o,
+ input iwb_we_i,
+ output reg iwb_ack_o,
+ input iwb_stb_i,
+ input [3:0] iwb_sel_i,
+
+ input [AWIDTH-1:0] dwb_adr_i,
+ input [31:0] dwb_dat_i,
+ output reg [31:0] dwb_dat_o,
+ input dwb_we_i,
+ output reg dwb_ack_o,
+ input dwb_stb_i,
+ input [3:0] dwb_sel_i);
+
+ reg [7:0] ram0 [0:(1<<(AWIDTH-2))-1];
+ reg [7:0] ram1 [0:(1<<(AWIDTH-2))-1];
+ reg [7:0] ram2 [0:(1<<(AWIDTH-2))-1];
+ reg [7:0] ram3 [0:(1<<(AWIDTH-2))-1];
+
+ // Instruction Read Port
+ always @(posedge wb_clk_i)
+ iwb_ack_o <= iwb_stb_i & ~iwb_ack_o;
+
+ always @(posedge wb_clk_i)
+ iwb_dat_o[31:24] <= ram3[iwb_adr_i[AWIDTH-1:2]];
+ always @(posedge wb_clk_i)
+ iwb_dat_o[23:16] <= ram2[iwb_adr_i[AWIDTH-1:2]];
+ always @(posedge wb_clk_i)
+ iwb_dat_o[15:8] <= ram1[iwb_adr_i[AWIDTH-1:2]];
+ always @(posedge wb_clk_i)
+ iwb_dat_o[7:0] <= ram0[iwb_adr_i[AWIDTH-1:2]];
+
+ always @(posedge wb_clk_i)
+ if(iwb_we_i & iwb_stb_i & iwb_sel_i[3])
+ ram3[iwb_adr_i[AWIDTH-1:2]] <= iwb_dat_i[31:24];
+ always @(posedge wb_clk_i)
+ if(iwb_we_i & iwb_stb_i & iwb_sel_i[2])
+ ram2[iwb_adr_i[AWIDTH-1:2]] <= iwb_dat_i[23:16];
+ always @(posedge wb_clk_i)
+ if(iwb_we_i & iwb_stb_i & iwb_sel_i[1])
+ ram1[iwb_adr_i[AWIDTH-1:2]] <= iwb_dat_i[15:8];
+ always @(posedge wb_clk_i)
+ if(iwb_we_i & iwb_stb_i & iwb_sel_i[0])
+ ram0[iwb_adr_i[AWIDTH-1:2]] <= iwb_dat_i[7:0];
+
+ // Data Port
+ always @(posedge wb_clk_i)
+ dwb_ack_o <= dwb_stb_i & ~dwb_ack_o;
+
+ always @(posedge wb_clk_i)
+ dwb_dat_o[31:24] <= ram3[dwb_adr_i[AWIDTH-1:2]];
+ always @(posedge wb_clk_i)
+ dwb_dat_o[23:16] <= ram2[dwb_adr_i[AWIDTH-1:2]];
+ always @(posedge wb_clk_i)
+ dwb_dat_o[15:8] <= ram1[dwb_adr_i[AWIDTH-1:2]];
+ always @(posedge wb_clk_i)
+ dwb_dat_o[7:0] <= ram0[dwb_adr_i[AWIDTH-1:2]];
+
+ always @(posedge wb_clk_i)
+ if(dwb_we_i & dwb_stb_i & dwb_sel_i[3])
+ ram3[dwb_adr_i[AWIDTH-1:2]] <= dwb_dat_i[31:24];
+ always @(posedge wb_clk_i)
+ if(dwb_we_i & dwb_stb_i & dwb_sel_i[2])
+ ram2[dwb_adr_i[AWIDTH-1:2]] <= dwb_dat_i[23:16];
+ always @(posedge wb_clk_i)
+ if(dwb_we_i & dwb_stb_i & dwb_sel_i[1])
+ ram1[dwb_adr_i[AWIDTH-1:2]] <= dwb_dat_i[15:8];
+ always @(posedge wb_clk_i)
+ if(dwb_we_i & dwb_stb_i & dwb_sel_i[0])
+ ram0[dwb_adr_i[AWIDTH-1:2]] <= dwb_dat_i[7:0];
+
+endmodule // ram_wb_harvard
+