Rename "spiflash" example to "picosoc"

1 files changed, 111 insertions, 0 deletions

diff --git a/picosoc/picosoc.v b/picosoc/picosoc.v
new file mode 100644
index 0000000..d1b01dd
--- /dev/null
+++ b/picosoc/picosoc.v
@@ -0,0 +1,111 @@
+/*
+ *  PicoSoC - A simple example SoC using PicoRV32
+ *
+ *  Copyright (C) 2017  Clifford Wolf <clifford@clifford.at>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+module picosoc (
+	input clk,
+	output trap,
+
+	input [31:0] gpio_i,
+	output reg [31:0] gpio_o,
+
+	output flash_csb,
+	output flash_clk,
+	output flash_io0,
+	input  flash_io1,
+	input  flash_io2,
+	input  flash_io3
+);
+	parameter integer MEM_WORDS = 256;
+	parameter [31:0] STACKADDR = (4*MEM_WORDS);       // end of memory
+	parameter [31:0] PROGADDR_RESET = 32'h 8010_0000; // 1 MB into flash
+
+	reg [5:0] reset_cnt = 0;
+	wire resetn = &reset_cnt;
+
+	always @(posedge clk) begin
+		reset_cnt <= reset_cnt + !resetn;
+	end
+
+	wire mem_valid;
+	wire mem_instr;
+	reg mem_ready;
+	wire [31:0] mem_addr;
+	wire [31:0] mem_wdata;
+	wire [3:0] mem_wstrb;
+	reg  [31:0] mem_rdata;
+
+	wire spimem_ready;
+	wire [31:0] spimem_rdata;
+
+	picorv32 #(
+		.STACKADDR(STACKADDR),
+		.PROGADDR_RESET(PROGADDR_RESET)
+	) cpu (
+		.clk         (clk        ),
+		.resetn      (resetn     ),
+		.trap        (trap       ),
+		.mem_valid   (mem_valid  ),
+		.mem_instr   (mem_instr  ),
+		.mem_ready   (mem_ready  || spimem_ready),
+		.mem_addr    (mem_addr   ),
+		.mem_wdata   (mem_wdata  ),
+		.mem_wstrb   (mem_wstrb  ),
+		.mem_rdata   (spimem_ready ? spimem_rdata : mem_rdata  )
+	);
+
+	spimemio spimemio (
+		.clk(clk),
+		.resetn(resetn),
+		.valid (mem_valid && mem_addr[31:30] == 2'b10),
+		.ready (spimem_ready),
+		.addr  (mem_addr[23:0]),
+		.rdata (spimem_rdata),
+
+		.flash_csb (flash_csb),
+		.flash_clk (flash_clk),
+		.flash_io0 (flash_io0),
+		.flash_io1 (flash_io1),
+		.flash_io2 (flash_io2),
+		.flash_io3 (flash_io3)
+	);
+
+	reg [31:0] memory [0:MEM_WORDS-1];
+
+	always @(posedge clk) begin
+		mem_ready <= 0;
+		if (mem_valid && !mem_ready) begin
+			if (mem_addr < 4*MEM_WORDS) begin
+				mem_ready <= 1;
+				mem_rdata <= memory[mem_addr >> 2];
+				if (mem_wstrb[0]) memory[mem_addr >> 2][ 7: 0] <= mem_wdata[ 7: 0];
+				if (mem_wstrb[1]) memory[mem_addr >> 2][15: 8] <= mem_wdata[15: 8];
+				if (mem_wstrb[2]) memory[mem_addr >> 2][23:16] <= mem_wdata[23:16];
+				if (mem_wstrb[3]) memory[mem_addr >> 2][31:24] <= mem_wdata[31:24];
+			end
+			if (mem_addr == 32'h c000_0000) begin
+				mem_ready <= 1;
+				mem_rdata <= gpio_i;
+				if (mem_wstrb[0]) gpio_o[ 7: 0] <= mem_wdata[ 7: 0];
+				if (mem_wstrb[1]) gpio_o[15: 8] <= mem_wdata[15: 8];
+				if (mem_wstrb[2]) gpio_o[23:16] <= mem_wdata[23:16];
+				if (mem_wstrb[3]) gpio_o[31:24] <= mem_wdata[31:24];
+			end
+		end
+	end
+endmodule