| module uart_tx_tb (); | |
| reg clock; | |
| reg [7:0] read_data; | |
| reg read_clock_enable; | |
| reg reset; /* active low */ | |
| wire ready; /* ready to read new data */ | |
| wire tx; | |
| wire uart_clock; | |
| uart_tx #(.CLOCK_FREQ(2_400), .BAUD_RATE(1_200)) | |
| UART ( | |
| .reset(reset), | |
| .clock(clock), | |
| .read_data(read_data), | |
| .read_clock_enable(read_clock_enable), | |
| .tx(tx), | |
| .ready(ready), | |
| .uart_clock(uart_clock)); | |
| always | |
| #2 clock = ~clock; | |
| initial begin | |
| #5000 $finish; | |
| end | |
| initial begin | |
| $dumpfile ("uart_tx_tb.vcd"); | |
| $dumpvars (0, uart_tx_tb); | |
| clock = 0; | |
| reset = 0; | |
| read_data = 8'hb7; | |
| read_clock_enable = 1; | |
| #10 | |
| if (ready == 'b1) begin | |
| $display("ready in reset is high. Expected: low"); | |
| $stop; | |
| end | |
| #2 | |
| read_clock_enable = 0; | |
| #20 reset = 1; | |
| #2; | |
| #2; | |
| #2; | |
| reset = 1; | |
| #500; | |
| if (ready == 'b0) begin | |
| $display("ready after reset is low. Expected: high"); | |
| $stop; | |
| end | |
| #2; | |
| read_clock_enable = 1; | |
| @(negedge ready); | |
| read_clock_enable = 0; | |
| #2000; | |
| $finish; | |
| end | |
| endmodule | |