// pinmux.sv — two pads shared between GPIO, UART, SPI and test functions
module pinmux (
  input  logic [1:0] mode,          // 0 GPIO, 1 UART, 2 SPI, 3 test
  input  logic       gpio_out0, gpio_out1,
  input  logic       uart_tx,
  input  logic       spi_sclk, spi_mosi,
  input  logic       test_obs0, test_obs1,
  output logic       pad0, pad1
);
  always_comb begin
    case (mode)
      2'd0:    begin pad0 = gpio_out0; pad1 = gpio_out1; end
      2'd1:    begin pad0 = uart_tx;   pad1 = 1'b1;      end  // pad1 idles high in UART mode
      2'd2:    begin pad0 = spi_sclk;  pad1 = spi_mosi;  end
      default: begin pad0 = test_obs0; pad1 = test_obs1; end
    endcase
  end
endmodule