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Apple1_MiST/rtl/mist-modules/user_io.v
nino-porcino 03281591f6 fork Gehstock's project
2021-12-29 16:18:10 +01:00

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//
// user_io.v
//
// user_io for the MiST board
// http://code.google.com/p/mist-board/
//
// Copyright (c) 2014 Till Harbaum <till@harbaum.org>
//
// This source file is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This source file is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// parameter STRLEN and the actual length of conf_str have to match
module user_io (
input [(8*STRLEN)-1:0] conf_str,
output [9:0] conf_addr, // RAM address for config string, if STRLEN=0
input [7:0] conf_chr,
input clk_sys, // clock for system-related messages (kbd, joy, etc...)
input clk_sd, // clock for SD-card related messages
input SPI_CLK,
input SPI_SS_IO,
output reg SPI_MISO,
input SPI_MOSI,
output reg [31:0] joystick_0,
output reg [31:0] joystick_1,
output reg [31:0] joystick_2,
output reg [31:0] joystick_3,
output reg [31:0] joystick_4,
output reg [31:0] joystick_analog_0,
output reg [31:0] joystick_analog_1,
output [1:0] buttons,
output [1:0] switches,
output scandoubler_disable,
output ypbpr,
output no_csync,
output reg [63:0] status,
output reg [6:0] core_mod, // core variant, sent before the config string is requested
// RTC data from IO controller
// sec, min, hour, date, month, year, day (BCD)
output reg [63:0] rtc,
// connection to sd card emulation
input [31:0] sd_lba,
input [SD_IMAGES-1:0] sd_rd,
input [SD_IMAGES-1:0] sd_wr,
output reg sd_ack,
output reg sd_ack_conf,
input sd_conf,
input sd_sdhc,
output reg [7:0] sd_dout, // valid on rising edge of sd_dout_strobe
output reg sd_dout_strobe,
input [7:0] sd_din,
output reg sd_din_strobe,
output reg [8:0] sd_buff_addr,
output reg [SD_IMAGES-1:0] img_mounted, // rising edge if a new image is mounted
output reg [63:0] img_size, // size of image in bytes
// ps2 keyboard/mouse emulation
output ps2_kbd_clk,
output reg ps2_kbd_data,
input ps2_kbd_clk_i,
input ps2_kbd_data_i,
output ps2_mouse_clk,
output reg ps2_mouse_data,
input ps2_mouse_clk_i,
input ps2_mouse_data_i,
// keyboard data
output reg key_pressed, // 1-make (pressed), 0-break (released)
output reg key_extended, // extended code
output reg [7:0] key_code, // key scan code
output reg key_strobe, // key data valid
// mouse data
output reg [8:0] mouse_x,
output reg [8:0] mouse_y,
output reg [3:0] mouse_z,
output reg [7:0] mouse_flags, // YOvfl, XOvfl, dy8, dx8, 1, mbtn, rbtn, lbtn
output reg mouse_strobe, // mouse data is valid on mouse_strobe
output reg mouse_idx, // which mouse?
// serial com port
input [7:0] serial_data,
input serial_strobe
);
parameter STRLEN=0; // config string length
parameter PS2DIV=100; // master clock divider for psk2_kbd/mouse clk
parameter ROM_DIRECT_UPLOAD=0; // direct upload used for file uploads from the ARM
parameter SD_IMAGES=2; // number of block-access images (max. 4 supported in current firmware)
parameter PS2BIDIR=0; // bi-directional PS2 interface
parameter FEATURES=0; // requested features from the firmware
localparam W = $clog2(SD_IMAGES);
reg [6:0] sbuf;
reg [7:0] cmd;
reg [2:0] bit_cnt; // counts bits 0-7 0-7 ...
reg [9:0] byte_cnt; // counts bytes
reg [7:0] but_sw;
reg [2:0] stick_idx;
assign buttons = but_sw[1:0];
assign switches = but_sw[3:2];
assign scandoubler_disable = but_sw[4];
assign ypbpr = but_sw[5];
assign no_csync = but_sw[6];
assign conf_addr = byte_cnt;
// this variant of user_io is for 8 bit cores (type == a4) only
// bit 4 indicates ROM direct upload capability
wire [7:0] core_type = ROM_DIRECT_UPLOAD ? 8'hb4 : 8'ha4;
reg [W:0] drive_sel;
always begin
integer i;
drive_sel = 0;
for(i = 0; i < SD_IMAGES; i = i + 1) if(sd_rd[i] | sd_wr[i]) drive_sel = i[W:0];
end
// command byte read by the io controller
wire [7:0] sd_cmd = { 4'h6, sd_conf, sd_sdhc, sd_wr[drive_sel], sd_rd[drive_sel] };
wire spi_sck = SPI_CLK;
// ---------------- PS2 ---------------------
// 16 byte fifos to store ps2 bytes
localparam PS2_FIFO_BITS = 4;
reg ps2_clk;
always @(posedge clk_sys) begin
integer cnt;
cnt <= cnt + 1'd1;
if(cnt == PS2DIV) begin
ps2_clk <= ~ps2_clk;
cnt <= 0;
end
end
// keyboard
reg [7:0] ps2_kbd_fifo [(2**PS2_FIFO_BITS)-1:0];
reg [PS2_FIFO_BITS-1:0] ps2_kbd_wptr;
reg [PS2_FIFO_BITS-1:0] ps2_kbd_rptr;
// ps2 transmitter state machine
reg [3:0] ps2_kbd_tx_state;
reg [7:0] ps2_kbd_tx_byte;
reg ps2_kbd_parity;
// ps2 receiver state machine
reg [3:0] ps2_kbd_rx_state = 0;
reg [1:0] ps2_kbd_rx_start = 0;
reg [7:0] ps2_kbd_rx_byte = 0;
reg ps2_kbd_rx_strobe = 0;
assign ps2_kbd_clk = ps2_clk || (ps2_kbd_tx_state == 0 && ps2_kbd_rx_state == 0);
// ps2 transmitter/receiver
// Takes a byte from the FIFO and sends it in a ps2 compliant serial format.
// Sends a command to the IO controller if bidirectional mode is enabled.
always@(posedge clk_sys) begin : ps2_kbd
reg ps2_clkD;
reg ps2_clk_iD, ps2_dat_iD;
reg ps2_kbd_r_inc;
// send data
ps2_clkD <= ps2_clk;
if (~ps2_clkD & ps2_clk) begin
ps2_kbd_r_inc <= 1'b0;
if(ps2_kbd_r_inc)
ps2_kbd_rptr <= ps2_kbd_rptr + 1'd1;
// transmitter is idle?
if(ps2_kbd_tx_state == 0) begin
ps2_kbd_data <= 1;
// data in fifo present?
if(ps2_kbd_wptr != ps2_kbd_rptr && (ps2_kbd_clk_i | !PS2BIDIR)) begin
// load tx register from fifo
ps2_kbd_tx_byte <= ps2_kbd_fifo[ps2_kbd_rptr];
ps2_kbd_r_inc <= 1'b1;
// reset parity
ps2_kbd_parity <= 1'b1;
// start transmitter
ps2_kbd_tx_state <= 4'd1;
// put start bit on data line
ps2_kbd_data <= 1'b0; // start bit is 0
end
end else begin
// transmission of 8 data bits
if((ps2_kbd_tx_state >= 1)&&(ps2_kbd_tx_state < 9)) begin
ps2_kbd_data <= ps2_kbd_tx_byte[0]; // data bits
ps2_kbd_tx_byte[6:0] <= ps2_kbd_tx_byte[7:1]; // shift down
if(ps2_kbd_tx_byte[0])
ps2_kbd_parity <= !ps2_kbd_parity;
end
// transmission of parity
if(ps2_kbd_tx_state == 9)
ps2_kbd_data <= ps2_kbd_parity;
// transmission of stop bit
if(ps2_kbd_tx_state == 10)
ps2_kbd_data <= 1'b1; // stop bit is 1
// advance state machine
if(ps2_kbd_tx_state < 11)
ps2_kbd_tx_state <= ps2_kbd_tx_state + 4'd1;
else
ps2_kbd_tx_state <= 4'd0;
end
end
if (PS2BIDIR) begin
ps2_clk_iD <= ps2_kbd_clk_i;
ps2_dat_iD <= ps2_kbd_data_i;
// receive command
case (ps2_kbd_rx_start)
2'd0:
// first: host pulls down the clock line
if (ps2_clk_iD & ~ps2_kbd_clk_i) ps2_kbd_rx_start <= 1;
2'd1:
// second: host pulls down the data line, while releasing the clock
if (ps2_dat_iD && !ps2_kbd_data_i) ps2_kbd_rx_start <= 2'd2;
// if it releases the clock without pulling down the data line: goto 0
else if (ps2_kbd_clk_i) ps2_kbd_rx_start <= 0;
2'd2:
if (ps2_clkD && ~ps2_clk) begin
ps2_kbd_rx_state <= 4'd1;
ps2_kbd_rx_start <= 0;
end
default: ;
endcase
// host data is valid after the rising edge of the clock
if(ps2_kbd_rx_state != 0 && ~ps2_clkD && ps2_clk) begin
ps2_kbd_rx_state <= ps2_kbd_rx_state + 1'd1;
if (ps2_kbd_rx_state == 9) ;// parity
else if (ps2_kbd_rx_state == 10) begin
ps2_kbd_data <= 0; // ack the received byte
end else if (ps2_kbd_rx_state == 11) begin
ps2_kbd_rx_state <= 0;
ps2_kbd_rx_strobe <= ~ps2_kbd_rx_strobe;
end else begin
ps2_kbd_rx_byte <= {ps2_kbd_data_i, ps2_kbd_rx_byte[7:1]};
end
end
end
end
// mouse
reg [7:0] ps2_mouse_fifo [(2**PS2_FIFO_BITS)-1:0];
reg [PS2_FIFO_BITS-1:0] ps2_mouse_wptr;
reg [PS2_FIFO_BITS-1:0] ps2_mouse_rptr;
// ps2 transmitter state machine
reg [3:0] ps2_mouse_tx_state;
reg [7:0] ps2_mouse_tx_byte;
reg ps2_mouse_parity;
// ps2 receiver state machine
reg [3:0] ps2_mouse_rx_state = 0;
reg [1:0] ps2_mouse_rx_start = 0;
reg [7:0] ps2_mouse_rx_byte = 0;
reg ps2_mouse_rx_strobe = 0;
assign ps2_mouse_clk = ps2_clk || (ps2_mouse_tx_state == 0 && ps2_mouse_rx_state == 0);
// ps2 transmitter/receiver
// Takes a byte from the FIFO and sends it in a ps2 compliant serial format.
// Sends a command to the IO controller if bidirectional mode is enabled.
always@(posedge clk_sys) begin : ps2_mouse
reg ps2_clkD;
reg ps2_clk_iD, ps2_dat_iD;
reg ps2_mouse_r_inc;
ps2_clkD <= ps2_clk;
if (~ps2_clkD & ps2_clk) begin
ps2_mouse_r_inc <= 1'b0;
if(ps2_mouse_r_inc)
ps2_mouse_rptr <= ps2_mouse_rptr + 1'd1;
// transmitter is idle?
if(ps2_mouse_tx_state == 0) begin
ps2_mouse_data <= 1;
// data in fifo present?
if(ps2_mouse_wptr != ps2_mouse_rptr && (ps2_mouse_clk_i | !PS2BIDIR)) begin
// load tx register from fifo
ps2_mouse_tx_byte <= ps2_mouse_fifo[ps2_mouse_rptr];
ps2_mouse_r_inc <= 1'b1;
// reset parity
ps2_mouse_parity <= 1'b1;
// start transmitter
ps2_mouse_tx_state <= 4'd1;
// put start bit on data line
ps2_mouse_data <= 1'b0; // start bit is 0
end
end else begin
// transmission of 8 data bits
if((ps2_mouse_tx_state >= 1)&&(ps2_mouse_tx_state < 9)) begin
ps2_mouse_data <= ps2_mouse_tx_byte[0]; // data bits
ps2_mouse_tx_byte[6:0] <= ps2_mouse_tx_byte[7:1]; // shift down
if(ps2_mouse_tx_byte[0])
ps2_mouse_parity <= !ps2_mouse_parity;
end
// transmission of parity
if(ps2_mouse_tx_state == 9)
ps2_mouse_data <= ps2_mouse_parity;
// transmission of stop bit
if(ps2_mouse_tx_state == 10)
ps2_mouse_data <= 1'b1; // stop bit is 1
// advance state machine
if(ps2_mouse_tx_state < 11)
ps2_mouse_tx_state <= ps2_mouse_tx_state + 4'd1;
else
ps2_mouse_tx_state <= 4'd0;
end
end
if (PS2BIDIR) begin
ps2_clk_iD <= ps2_mouse_clk_i;
ps2_dat_iD <= ps2_mouse_data_i;
// receive command
case (ps2_mouse_rx_start)
2'd0:
// first: host pulls down the clock line
if (ps2_clk_iD & ~ps2_mouse_clk_i) ps2_mouse_rx_start <= 1;
2'd1:
// second: host pulls down the data line, while releasing the clock
if (ps2_dat_iD && !ps2_mouse_data_i) ps2_mouse_rx_start <= 2'd2;
// if it releases the clock without pulling down the data line: goto 0
else if (ps2_mouse_clk_i) ps2_mouse_rx_start <= 0;
2'd2:
if (ps2_clkD && ~ps2_clk) begin
ps2_mouse_rx_state <= 4'd1;
ps2_mouse_rx_start <= 0;
end
default: ;
endcase
// host data is valid after the rising edge of the clock
if(ps2_mouse_rx_state != 0 && ~ps2_clkD && ps2_clk) begin
ps2_mouse_rx_state <= ps2_mouse_rx_state + 1'd1;
if (ps2_mouse_rx_state == 9) ;// parity
else if (ps2_mouse_rx_state == 10) begin
ps2_mouse_data <= 0; // ack the received byte
end else if (ps2_mouse_rx_state == 11) begin
ps2_mouse_rx_state <= 0;
ps2_mouse_rx_strobe <= ~ps2_mouse_rx_strobe;
end else begin
ps2_mouse_rx_byte <= {ps2_mouse_data_i, ps2_mouse_rx_byte[7:1]};
end
end
end
end
// fifo to receive serial data from core to be forwarded to io controller
// 16 byte fifo to store serial bytes
localparam SERIAL_OUT_FIFO_BITS = 6;
reg [7:0] serial_out_fifo [(2**SERIAL_OUT_FIFO_BITS)-1:0];
reg [SERIAL_OUT_FIFO_BITS-1:0] serial_out_wptr;
reg [SERIAL_OUT_FIFO_BITS-1:0] serial_out_rptr;
wire serial_out_data_available = serial_out_wptr != serial_out_rptr;
wire [7:0] serial_out_byte = serial_out_fifo[serial_out_rptr] /* synthesis keep */;
wire [7:0] serial_out_status = { 7'b1000000, serial_out_data_available};
// status[0] is reset signal from io controller and is thus used to flush
// the fifo
always @(posedge serial_strobe or posedge status[0]) begin : serial_out
if(status[0] == 1) begin
serial_out_wptr <= 0;
end else begin
serial_out_fifo[serial_out_wptr] <= serial_data;
serial_out_wptr <= serial_out_wptr + 1'd1;
end
end
always@(negedge spi_sck or posedge status[0]) begin : serial_in
if(status[0] == 1) begin
serial_out_rptr <= 0;
end else begin
if((byte_cnt != 0) && (cmd == 8'h1b)) begin
// read last bit -> advance read pointer
if((bit_cnt == 7) && !byte_cnt[0] && serial_out_data_available)
serial_out_rptr <= serial_out_rptr + 1'd1;
end
end
end
// SPI bit and byte counters
always@(posedge spi_sck or posedge SPI_SS_IO) begin : spi_counter
if(SPI_SS_IO == 1) begin
bit_cnt <= 0;
byte_cnt <= 0;
end else begin
if((bit_cnt == 7)&&(~&byte_cnt))
byte_cnt <= byte_cnt + 8'd1;
bit_cnt <= bit_cnt + 1'd1;
end
end
// SPI transmitter FPGA -> IO
reg [7:0] spi_byte_out;
always@(negedge spi_sck or posedge SPI_SS_IO) begin : spi_byteout
if(SPI_SS_IO == 1) begin
SPI_MISO <= 1'bZ;
end else begin
SPI_MISO <= spi_byte_out[~bit_cnt];
end
end
always@(posedge spi_sck or posedge SPI_SS_IO) begin : spi_transmitter
reg [31:0] sd_lba_r;
reg [W:0] drive_sel_r;
reg ps2_kbd_rx_strobeD;
reg ps2_mouse_rx_strobeD;
if(SPI_SS_IO == 1) begin
spi_byte_out <= core_type;
end else begin
// read the command byte to choose the response
if(bit_cnt == 7) begin
if(!byte_cnt) cmd <= {sbuf, SPI_MOSI};
spi_byte_out <= 0;
case({(!byte_cnt) ? {sbuf, SPI_MOSI} : cmd})
// PS2 keyboard command
8'h0e: if (byte_cnt == 0) begin
ps2_kbd_rx_strobeD <= ps2_kbd_rx_strobe;
//echo the command code if there's a byte to send, indicating the core supports the command
spi_byte_out <= (ps2_kbd_rx_strobe ^ ps2_kbd_rx_strobeD) ? 8'h0e : 8'h00;
end else spi_byte_out <= ps2_kbd_rx_byte;
// PS2 mouse command
8'h0f: if (byte_cnt == 0) begin
ps2_mouse_rx_strobeD <= ps2_mouse_rx_strobe;
//echo the command code if there's a byte to send, indicating the core supports the command
spi_byte_out <= (ps2_mouse_rx_strobe ^ ps2_mouse_rx_strobeD) ? 8'h0f : 8'h00;
end else spi_byte_out <= ps2_mouse_rx_byte;
// reading config string
8'h14: if (STRLEN == 0) spi_byte_out <= conf_chr; else
if(byte_cnt < STRLEN) spi_byte_out <= conf_str[(STRLEN - byte_cnt - 1)<<3 +:8];
// reading sd card status
8'h16: if(byte_cnt == 0) begin
spi_byte_out <= sd_cmd;
sd_lba_r <= sd_lba;
drive_sel_r <= drive_sel;
end
else if(byte_cnt == 1) spi_byte_out <= drive_sel_r;
else if(byte_cnt < 6) spi_byte_out <= sd_lba_r[(5-byte_cnt)<<3 +:8];
// reading sd card write data
8'h18: spi_byte_out <= sd_din;
8'h1b:
// send alternating flag byte and data
if(byte_cnt[0]) spi_byte_out <= serial_out_status;
else spi_byte_out <= serial_out_byte;
// core features
8'h80:
if (byte_cnt == 0) spi_byte_out <= 8'h80;
else spi_byte_out <= FEATURES[(4-byte_cnt)<<3 +:8];
endcase
end
end
end
// SPI receiver IO -> FPGA
reg spi_receiver_strobe_r = 0;
reg spi_transfer_end_r = 1;
reg [7:0] spi_byte_in;
// Read at spi_sck clock domain, assemble bytes for transferring to clk_sys
always@(posedge spi_sck or posedge SPI_SS_IO) begin : spi_receiver
if(SPI_SS_IO == 1) begin
spi_transfer_end_r <= 1;
end else begin
spi_transfer_end_r <= 0;
if(bit_cnt != 7)
sbuf[6:0] <= { sbuf[5:0], SPI_MOSI };
// finished reading a byte, prepare to transfer to clk_sys
if(bit_cnt == 7) begin
spi_byte_in <= { sbuf, SPI_MOSI};
spi_receiver_strobe_r <= ~spi_receiver_strobe_r;
end
end
end
// Process bytes from SPI at the clk_sys domain
always @(posedge clk_sys) begin : cmd_block
reg spi_receiver_strobe;
reg spi_transfer_end;
reg spi_receiver_strobeD;
reg spi_transfer_endD;
reg [7:0] acmd;
reg [7:0] abyte_cnt; // counts bytes
reg [7:0] mouse_flags_r;
reg [7:0] mouse_x_r;
reg [7:0] mouse_y_r;
reg key_pressed_r;
reg key_extended_r;
//synchronize between SPI and sys clock domains
spi_receiver_strobeD <= spi_receiver_strobe_r;
spi_receiver_strobe <= spi_receiver_strobeD;
spi_transfer_endD <= spi_transfer_end_r;
spi_transfer_end <= spi_transfer_endD;
key_strobe <= 0;
mouse_strobe <= 0;
if (spi_transfer_end) begin
abyte_cnt <= 8'd0;
end else if (spi_receiver_strobeD ^ spi_receiver_strobe) begin
if(~&abyte_cnt)
abyte_cnt <= abyte_cnt + 8'd1;
if(abyte_cnt == 0) begin
acmd <= spi_byte_in;
end else begin
case(acmd)
// buttons and switches
8'h01: but_sw <= spi_byte_in;
8'h60: if (abyte_cnt < 5) joystick_0[(abyte_cnt-1)<<3 +:8] <= spi_byte_in;
8'h61: if (abyte_cnt < 5) joystick_1[(abyte_cnt-1)<<3 +:8] <= spi_byte_in;
8'h62: if (abyte_cnt < 5) joystick_2[(abyte_cnt-1)<<3 +:8] <= spi_byte_in;
8'h63: if (abyte_cnt < 5) joystick_3[(abyte_cnt-1)<<3 +:8] <= spi_byte_in;
8'h64: if (abyte_cnt < 5) joystick_4[(abyte_cnt-1)<<3 +:8] <= spi_byte_in;
8'h70,8'h71: begin
// store incoming ps2 mouse bytes
if (abyte_cnt < 4) begin
ps2_mouse_fifo[ps2_mouse_wptr] <= spi_byte_in;
ps2_mouse_wptr <= ps2_mouse_wptr + 1'd1;
end
if (abyte_cnt == 1) mouse_flags_r <= spi_byte_in;
else if (abyte_cnt == 2) mouse_x_r <= spi_byte_in;
else if (abyte_cnt == 3) mouse_y_r <= spi_byte_in;
else if (abyte_cnt == 4) begin
// flags: YOvfl, XOvfl, dy8, dx8, 1, mbtn, rbtn, lbtn
mouse_flags <= mouse_flags_r;
mouse_x <= { mouse_flags_r[4], mouse_x_r };
mouse_y <= { mouse_flags_r[5], mouse_y_r };
mouse_z <= spi_byte_in[3:0];
mouse_idx <= acmd[0];
mouse_strobe <= 1;
end
end
8'h05: begin
// store incoming ps2 keyboard bytes
ps2_kbd_fifo[ps2_kbd_wptr] <= spi_byte_in;
ps2_kbd_wptr <= ps2_kbd_wptr + 1'd1;
if (abyte_cnt == 1) begin
key_extended_r <= 0;
key_pressed_r <= 1;
end
if (spi_byte_in == 8'he0) key_extended_r <= 1'b1;
else if (spi_byte_in == 8'hf0) key_pressed_r <= 1'b0;
else begin
key_extended <= key_extended_r && abyte_cnt != 1;
key_pressed <= key_pressed_r || abyte_cnt == 1;
key_code <= spi_byte_in;
key_strobe <= 1'b1;
end
end
// joystick analog
8'h1a: begin
// first byte is joystick index
if(abyte_cnt == 1)
stick_idx <= spi_byte_in[2:0];
else if(abyte_cnt == 2) begin
// second byte is x axis
if(stick_idx == 0)
joystick_analog_0[15:8] <= spi_byte_in;
else if(stick_idx == 1)
joystick_analog_1[15:8] <= spi_byte_in;
end else if(abyte_cnt == 3) begin
// third byte is y axis
if(stick_idx == 0)
joystick_analog_0[7:0] <= spi_byte_in;
else if(stick_idx == 1)
joystick_analog_1[7:0] <= spi_byte_in;
end else if(abyte_cnt == 4) begin
// fourth byte is 2nd x axis
if(stick_idx == 0)
joystick_analog_0[31:24] <= spi_byte_in;
else if(stick_idx == 1)
joystick_analog_1[31:24] <= spi_byte_in;
end else if(abyte_cnt == 5) begin
// fifth byte is 2nd y axis
if(stick_idx == 0)
joystick_analog_0[23:16] <= spi_byte_in;
else if(stick_idx == 1)
joystick_analog_1[23:16] <= spi_byte_in;
end
end
8'h15: status <= spi_byte_in;
// status, 64bit version
8'h1e: if(abyte_cnt<9) status[(abyte_cnt-1)<<3 +:8] <= spi_byte_in;
// core variant
8'h21: core_mod <= spi_byte_in[6:0];
// RTC
8'h22: if(abyte_cnt<9) rtc[(abyte_cnt-1)<<3 +:8] <= spi_byte_in;
endcase
end
end
end
// Process SD-card related bytes from SPI at the clk_sd domain
always @(posedge clk_sd) begin : sd_block
reg spi_receiver_strobe;
reg spi_transfer_end;
reg spi_receiver_strobeD;
reg spi_transfer_endD;
reg [SD_IMAGES-1:0] sd_wrD;
reg [7:0] acmd;
reg [7:0] abyte_cnt; // counts bytes
//synchronize between SPI and sd clock domains
spi_receiver_strobeD <= spi_receiver_strobe_r;
spi_receiver_strobe <= spi_receiver_strobeD;
spi_transfer_endD <= spi_transfer_end_r;
spi_transfer_end <= spi_transfer_endD;
if(sd_dout_strobe) begin
sd_dout_strobe<= 0;
if(~&sd_buff_addr) sd_buff_addr <= sd_buff_addr + 1'b1;
end
sd_din_strobe<= 0;
sd_wrD <= sd_wr;
// fetch the first byte immediately after the write command seen
if (|(~sd_wrD & sd_wr)) begin
sd_buff_addr <= 0;
sd_din_strobe <= 1;
end
img_mounted <= 0;
if (spi_transfer_end) begin
abyte_cnt <= 8'd0;
sd_ack <= 1'b0;
sd_ack_conf <= 1'b0;
sd_buff_addr <= 0;
end else if (spi_receiver_strobeD ^ spi_receiver_strobe) begin
if(~&abyte_cnt)
abyte_cnt <= abyte_cnt + 8'd1;
if(abyte_cnt == 0) begin
acmd <= spi_byte_in;
if(spi_byte_in == 8'h18) begin
sd_din_strobe <= 1'b1;
if(~&sd_buff_addr) sd_buff_addr <= sd_buff_addr + 1'b1;
end
if(spi_byte_in == 8'h19)
sd_ack_conf <= 1'b1;
if((spi_byte_in == 8'h17) || (spi_byte_in == 8'h18))
sd_ack <= 1'b1;
end else begin
case(acmd)
// send sector IO -> FPGA
8'h17,
// send SD config IO -> FPGA
8'h19: begin
// flag that download begins
sd_dout_strobe <= 1'b1;
sd_dout <= spi_byte_in;
end
// send sector FPGA -> IO
8'h18: begin
if(~&sd_buff_addr) begin
sd_din_strobe <= 1'b1;
sd_buff_addr <= sd_buff_addr + 1'b1;
end
end
8'h1c: img_mounted[spi_byte_in[W:0]] <= 1;
// send image info
8'h1d: if(abyte_cnt<9) img_size[(abyte_cnt-1)<<3 +:8] <= spi_byte_in;
endcase
end
end
end
endmodule
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