reg [31:0]  nxdev_rdata;
	reg [31:0]  iodev_rdata;
	wire [3:0]  xdev_valid  = iodev_mem_valid << cpu_mem_addr[29:28];
	wire [15:0]  iodev_valid = xdev_valid[3] << cpu_mem_addr[10:7];

	wire [31:0] iodev_rdata_sys;
	wire [ 0:0] iodev_valid_sys = iodev_valid[0:0];
	tri1 [ 0:0] iodev_wait_n_sys;

	wire [31:0] iodev_rdata_sysclock;
	wire [ 0:0] iodev_irq_sysclock;
	wire [ 0:0] iodev_valid_sysclock = iodev_valid[1:1];
	tri1 [ 0:0] iodev_wait_n_sysclock;

	wire [31:0] iodev_rdata_console;
	wire [ 0:0] iodev_irq_console;
	wire [ 0:0] iodev_valid_console = iodev_valid[2:2];
	tri1 [ 0:0] iodev_wait_n_console;

	wire [31:0] iodev_rdata_sdcard;
	wire [ 0:0] iodev_irq_sdcard;
	wire [ 0:0] iodev_valid_sdcard = iodev_valid[3:3];
	tri1 [ 0:0] iodev_wait_n_sdcard;

	wire [31:0] iodev_rdata_i2c;
	wire [ 0:0] iodev_irq_i2c;
	wire [ 0:0] iodev_valid_i2c = iodev_valid[4:4];
	tri1 [ 0:0] iodev_wait_n_i2c;

	wire [31:0] iodev_rdata_esp;
	wire [ 0:0] iodev_irq_esp;
	wire [ 0:0] iodev_valid_esp = iodev_valid[5:5];
	tri1 [ 0:0] iodev_wait_n_esp;

	wire [31:0] iodev_rdata_abc;
	wire [ 0:0] iodev_irq_abc;
	wire [ 0:0] iodev_valid_abc = iodev_valid[6:6];
	tri1 [ 0:0] iodev_wait_n_abc;

	wire [31:0] iodev_rdata_abcmemmap;
	wire [ 0:0] iodev_valid_abcmemmap = xdev_valid[0:0];
	tri1 [ 0:0] iodev_wait_n_abcmemmap;

	// I/O input MUX
	always_comb
		case (cpu_mem_addr[29:28])
			2'd0:	 iodev_rdata = iodev_rdata_abcmemmap;
			2'd3:
			case (cpu_mem_addr[10:7])
				4'd0:	 iodev_rdata = iodev_rdata_sys;
				4'd1:	 iodev_rdata = iodev_rdata_sysclock;
				4'd2:	 iodev_rdata = iodev_rdata_console;
				4'd3:	 iodev_rdata = iodev_rdata_sdcard;
				4'd4:	 iodev_rdata = iodev_rdata_i2c;
				4'd5:	 iodev_rdata = iodev_rdata_esp;
				4'd6:	 iodev_rdata = iodev_rdata_abc;
				default: iodev_rdata = 32'hffffffff;
			endcase
			default: iodev_rdata = 32'hffffffff;
		endcase

	tri0 [31:0] sys_irq;
	assign sys_irq[ 3] = iodev_irq_sysclock[0];
	assign sys_irq[ 4] = iodev_irq_console[0];
	assign sys_irq[ 5] = iodev_irq_sdcard[0];
	assign sys_irq[ 6] = iodev_irq_i2c[0];
	assign sys_irq[ 7] = iodev_irq_esp[0];
	assign sys_irq[ 8] = iodev_irq_abc[0];

	localparam [31:0] irq_edge_mask =  32'h00000148;
	localparam [31:0] irq_masked    = ~32'h000001ff;

	wire iodev_wait_n = (&iodev_wait_n_sys) & 
		(&iodev_wait_n_sysclock) & 
		(&iodev_wait_n_console) & 
		(&iodev_wait_n_sdcard) & 
		(&iodev_wait_n_i2c) & 
		(&iodev_wait_n_esp) & 
		(&iodev_wait_n_abc) & 
		(&iodev_wait_n_abcmemmap);