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Revision 70

Added by markw over 11 years ago

Added ZPU. Added read/write SD support. Fixed joystick. Switched to new mist keyboard mode (ps2 emulation).

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user_io.v
module user_io(
input SPI_CLK,
input SPI_SS_IO,
output reg SPI_MISO,
input SPI_MOSI,
input [7:0] CORE_TYPE,
output [5:0] JOY0,
output [5:0] JOY1,
output [127:0] KEYBOARD,
output [1:0] BUTTONS,
output [1:0] SWITCHES
);
reg [6:0] sbuf;
reg [7:0] cmd;
reg [7:0] cnt;
reg [5:0] joystick0;
reg [5:0] joystick1;
reg [119:0] keyboard;
reg [127:0] keyboard_out;
reg [3:0] but_sw;
assign JOY0 = joystick0;
assign JOY1 = joystick1;
assign KEYBOARD = keyboard_out;
assign BUTTONS = but_sw[1:0];
assign SWITCHES = but_sw[3:2];
always@(negedge SPI_CLK) begin
if(SPI_SS_IO == 1) begin
SPI_MISO <= 1'bZ;
end else begin
if(cnt < 8) begin
SPI_MISO <= CORE_TYPE[7-cnt];
end else begin
SPI_MISO <= 1'bZ;
end
end
end
always@(posedge SPI_CLK) begin
if(SPI_SS_IO == 1) begin
cnt <= 0;
end else begin
sbuf[6:1] <= sbuf[5:0];
sbuf[0] <= SPI_MOSI;
cnt <= cnt + 1;
if(cnt == 7) begin
cmd[7:1] <= sbuf;
cmd[0] <= SPI_MOSI;
end
if(cnt == 15) begin
if(cmd == 1) begin
but_sw[3:1] <= sbuf[2:0];
but_sw[0] <= SPI_MOSI;
end
if(cmd == 2) begin
joystick0[5:1] <= sbuf[4:0];
joystick0[0] <= SPI_MOSI;
end
if(cmd == 3) begin
joystick1[5:1] <= sbuf[4:0];
joystick1[0] <= SPI_MOSI;
end
end
// MiST user_io
module user_io(
input SPI_CLK,
input SPI_SS_IO,
output reg SPI_MISO,
input SPI_MOSI,
input [7:0] CORE_TYPE,
output [5:0] JOY0,
output [5:0] JOY1,
output [1:0] BUTTONS,
output [1:0] SWITCHES,
input clk,
output ps2_clk,
output reg ps2_data
);
reg [6:0] sbuf;
reg [7:0] cmd;
reg [4:0] cnt;
reg [5:0] joystick0;
reg [5:0] joystick1;
reg [3:0] but_sw;
assign JOY0 = joystick0;
assign JOY1 = joystick1;
assign BUTTONS = but_sw[1:0];
assign SWITCHES = but_sw[3:2];
// drive MISO only when transmitting core id
always@(negedge SPI_CLK or posedge SPI_SS_IO) begin
if(SPI_SS_IO == 1) begin
SPI_MISO <= 1'bZ;
end else begin
if(cnt < 8) begin
SPI_MISO <= CORE_TYPE[7-cnt];
end else begin
SPI_MISO <= 1'bZ;
end
end
end
// 8 byte fifo to store ps2 bytes
localparam PS2_FIFO_BITS = 3;
reg [7:0] ps2_fifo [(2**PS2_FIFO_BITS)-1:0];
reg [PS2_FIFO_BITS-1:0] ps2_wptr;
reg [PS2_FIFO_BITS-1:0] ps2_rptr;
// ps2 transmitter state machine
reg [3:0] ps2_tx_state;
reg [7:0] ps2_tx_byte;
reg ps2_parity;
assign ps2_clk = clk || (ps2_tx_state == 0);
// ps2 transmitter
// Takes a byte from the FIFO and sends it in a ps2 compliant serial format.
reg ps2_r_inc;
always@(posedge clk) begin
ps2_r_inc <= 1'b0;
if(ps2_r_inc)
ps2_rptr <= ps2_rptr + 1;
// transmitter is idle?
if(ps2_tx_state == 0) begin
// data in fifo present?
if(ps2_wptr != ps2_rptr) begin
// load tx register from fifo
ps2_tx_byte <= ps2_fifo[ps2_rptr];
ps2_r_inc <= 1'b1;
// 15,23,31,39,47,55,63,71
if (cnt[2:0]==7) begin
if(cmd == 5) begin
if (!cnt[7]) begin
keyboard[111:0] <= keyboard[119:8];
keyboard[119:113] <= sbuf[6:0];
keyboard[112] <= SPI_MOSI;
end
if (cnt[7]) begin
keyboard_out[119:0] <= keyboard[119:0];
keyboard_out[127:121] <= sbuf[6:0];
keyboard_out[120] <= SPI_MOSI;
end
end
// reset parity
ps2_parity <= 1'b1;
// start transmitter
ps2_tx_state <= 4'd1;
// put start bit on data line
ps2_data <= 1'b0; // start bit is 0
end
end else begin
// transmission of 8 data bits
if((ps2_tx_state >= 1)&&(ps2_tx_state < 9)) begin
ps2_data <= ps2_tx_byte[0]; // data bits
ps2_tx_byte[6:0] <= ps2_tx_byte[7:1]; // shift down
if(ps2_tx_byte[0])
ps2_parity <= !ps2_parity;
end
// transmission of parity
if(ps2_tx_state == 9)
ps2_data <= ps2_parity;
// transmission of stop bit
if(ps2_tx_state == 10)
ps2_data <= 1'b1; // stop bit is 1
// advance state machine
if(ps2_tx_state < 11)
ps2_tx_state <= ps2_tx_state + 4'd1;
else
ps2_tx_state <= 4'd0;
end
end
// SPI receiver
//reg ps2_w_inc;
always@(posedge SPI_CLK or posedge SPI_SS_IO) begin
// ps2_w_inc <= 1'b0;
// if(ps2_w_inc)
// ps2_wptr <= ps2_wptr + 1;
if(SPI_SS_IO == 1) begin
cnt <= 1'b0;
end else begin
sbuf[6:0] <= { sbuf[5:0], SPI_MOSI };
// counter counts 0-7, 8-15, 8-15 ...
// 0-7 is command, 8-15 is payload
if(cnt != 15) cnt <= cnt + 4'd1;
else cnt <= 4'd8;
// finished reading command byte
if(cnt == 7)
cmd <= { sbuf, SPI_MOSI};
if(cnt == 15) begin
if(cmd == 1)
but_sw <= { sbuf[2:0], SPI_MOSI };
if(cmd == 2)
joystick0 <= { sbuf[4:0], SPI_MOSI };
if(cmd == 3)
joystick1 <= { sbuf[4:0], SPI_MOSI };
if(cmd == 5) begin
// store incoming keyboard bytes in
ps2_fifo[ps2_wptr] <= { sbuf, SPI_MOSI };
ps2_wptr <= ps2_wptr + 1;
end
end
end
// always@(posedge clk2) begin
// LED <= ~LED;
// end
endmodule
end
end
end
endmodule

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