`define INST_CAR 4'b1111
`define INST_CDR 4'b1101
-`define STORE_BUTTON buttons[8]
-`define CLEAR_BUTTON buttons[9]
-`define PC_INC_BUTTON buttons[10]
-`define PC_DEC_BUTTON buttons[11]
-`define PC_CLR_BUTTON buttons[12]
-`define ACCUM_CLR_BUTTON buttons[13]
-`define RUN_BUTTON buttons[14]
-`define EXECUTE_BUTTON buttons[15]
-
`define GCOP_NOP 4'd0
`define GCOP_CDR 4'd1
`define GCOP_CAR 4'd2
// This is a simple four bit accumulator machine. It is a Havard architecture with separate
// program and user memory address spaces.
-module PROCESSOR (input clk, output [23:0] led, output [3:0] indicators, input [15:0] buttons, output uart_tx, input uart_rx);
+module PROCESSOR (input clk, output [4:0] led, output uart_tx, input uart_rx);
// storage unit
reg [7:0] Ein;
wire [7:0] Eout;
reg running = 1;
- always @ (posedge `RUN_BUTTON) begin
- running <= !running;
- end
-
- // Generate running clock
-
- wire running_counter;
-
- PRESCALER #(.BITS(1)) scal0 (.clk(clk), .out(running_counter));
-
- wire running_clk = running & running_counter;
-
- // Handle execution
-
- wire execute_trigger;
+ // Generate eval and gc clocks
- SINGLE_TRIGGER trig0 (.clk(clk), .trigger_in(`EXECUTE_BUTTON), .trigger_out(execute_trigger));
-
- wire running_trigger;
-
- SINGLE_TRIGGER trig1 (.clk(clk), .trigger_in(running_clk), .trigger_out(running_trigger));
-
- wire gc_clock = (!running & execute_trigger) | running_clk;
+ reg gc_clock = 0;
wire eval_clock = !gc_clock & step_eval;
+ always @ (posedge clk)
+ gc_clock <= !gc_clock;
+
GC gc (.clk(gc_clock), .mclk(clk), .Ein(Ein), .Eout(Eout), .gcop(gcop), .ostate(ostate), .step_eval(step_eval));
// Handle halt
wire [3:0] next = pc + 4'b0001;
wire [3:0] prev = pc + 4'b1111;
- wire pc_prev_trigger;
- wire pc_next_trigger;
- wire pc_zero_trigger;
-
- SINGLE_TRIGGER trig3 (.clk(clk), .trigger_in(`PC_INC_BUTTON), .trigger_out(pc_next_trigger));
- SINGLE_TRIGGER trig4 (.clk(clk), .trigger_in(`PC_DEC_BUTTON), .trigger_out(pc_prev_trigger));
- SINGLE_TRIGGER trig5 (.clk(clk), .trigger_in(`PC_CLR_BUTTON), .trigger_out(pc_zero_trigger));
-
wire [3:0] newPc =
(inst == `INST_JP) ? argu :
(inst == `INST_JPZ) & (accum == 4'b0000) ? argu :
(inst == `INST_READ) & !fifo_re ? pc :
(inst == `INST_RDQ) & !reading_E ? pc :
(inst != `INST_HALT) ? next :
-/* !running & pc_zero_trigger ? 4'b00000 :
- !running & pc_next_trigger ? next :
- !running & pc_prev_trigger ? prev : */
pc;
always @ (posedge eval_clock) begin
hex_to_ascii h2a (.hex(accum), .ascii(uart_tx_byte));
- // 300-ish baud uart
- uart #(.CLOCK_DIVIDE(81)) uart (.clk(clk), .rx(uart_rx), .tx(uart_tx), .transmit(uart_tx_signal), .tx_byte(uart_tx_byte), .received(uart_rx_signal), .rx_byte(uart_rx_byte), .is_receiving(uart_is_receiving), .is_transmitting(uart_is_transmitting), .recv_error (uart_rx_error));
+ // 300 baud uart
+ uart #(.CLOCK_DIVIDE(5)) uart (.clk(clk), .rx(uart_rx), .tx(uart_tx), .transmit(uart_tx_signal), .tx_byte(uart_tx_byte), .received(uart_rx_signal), .rx_byte(uart_rx_byte), .is_receiving(uart_is_receiving), .is_transmitting(uart_is_transmitting), .recv_error (uart_rx_error));
// GC logic
always @ (posedge eval_clock) begin
assign led[4] = uart_rx_error;
assign led[5] = fifo_empty;
assign led[6] = fifo_full;
- assign led[7] = fifo_re;*/
+ assign led[7] = fifo_re;
assign led[7:4] = Ein[3:0];
assign led[3:0] = Eout[3:0];
// assign led[15:8] = programOut;
// assign led[15:8] = uart_rx_byte;
- assign led[15] = step_eval;
- assign led[14] = eval_clock;
assign led[13:8] = ostate;
assign led[19:16] = pc;
assign led[23:20] = accum;
- assign indicators = {1'b0, (!running & `EXECUTE_BUTTON) | running_clk, halt, running & !halt};
+ assign indicators = {1'b0, (!running & `EXECUTE_BUTTON) | running_clk, halt, running & !halt};*/
+ assign led[0] = eval_clock;
+ assign led[1] = uart_is_transmitting;
+ assign led[2] = uart_is_receiving;
+ assign led[3] = recv_error;
endmodule