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`timescale 1ns / 1ps
// ////////////////////////////////////////////////////////////////////////////////
// Boot CPLD design, only for u2_rev2
// ////////////////////////////////////////////////////////////////////////////////
module boot_cpld
(input CLK_25MHZ,
output CLK_25MHZ_EN,
output [2:0] LED,
output [8:0] DEBUG,
input POR,
// To SD Card
output SD_nCS,
output SD_Din,
output SD_CLK,
input SD_Dout,
input SD_DAT1, // Unused
input SD_DAT2, // Unused
input SD_prot, // Write Protect
input SD_det, // Card Detect
// To FPGA Config Interface
input CFG_INIT_B,
output CFG_Din, // Also used in Data interface
output CFG_CCLK,
input CFG_DONE,
output CFG_PROG_B,
// To FPGA data interface
output CPLD_CLK,
input START,
input MODE,
input DONE,
output detached,
input CPLD_misc // Unused for now
);
assign CLK_25MHZ_EN = 1'b1;
assign LED[0] = ~CFG_DONE;
assign LED[1] = CFG_INIT_B;
assign LED[2] = ~CFG_PROG_B;
wire en_outs;
wire [3:0] set_sel = 4'd0;
assign CPLD_CLK = CFG_CCLK;
assign DEBUG[8:0] = { CLK_25MHZ, SD_nCS, SD_CLK, SD_Din, SD_Dout,
START, MODE, DONE, CPLD_misc};
// Handle cutover to FPGA control of SD
wire fpga_takeover = ~CPLD_misc;
wire SD_CLK_int, SD_nCS_int, SD_Din_int, CFG_Din_int;
assign SD_CLK = fpga_takeover ? START : SD_CLK_int;
assign SD_nCS = fpga_takeover ? MODE : SD_nCS_int;
assign SD_Din = fpga_takeover ? DONE : SD_Din_int;
assign CFG_Din = fpga_takeover ? SD_Dout : CFG_Din_int;
spi_boot #(.width_set_sel_g(4), // How many sets (16)
.width_bit_cnt_g(6), // Block length (12 is faster, 6 is minimum)
.width_img_cnt_g(2), // How many images per set
.num_bits_per_img_g(20), // Image size, 20 = 1MB
.sd_init_g(1), // SD-specific initialization
.mmc_compat_clk_div_g(0),// No MMC support
.width_mmc_clk_div_g(0), // No MMC support
.reset_level_g(0)) // Active low reset
spi_boot(.clk_i(CLK_25MHZ),
.reset_i(POR),
// To SD Card
.spi_clk_o(SD_CLK_int),
.spi_cs_n_o(SD_nCS_int),
.spi_data_in_i(SD_Dout),
.spi_data_out_o(SD_Din_int),
.spi_en_outs_o(en_outs),
// Data Port
.start_i(START),
.mode_i(MODE), // 0->conf mode, 1->data mode
.detached_o(detached),
.dat_done_i(DONE),
.set_sel_i(set_sel),
// To FPGA
.config_n_o(CFG_PROG_B),
.cfg_init_n_i(CFG_INIT_B),
.cfg_done_i(CFG_DONE),
.cfg_clk_o(CFG_CCLK),
.cfg_dat_o(CFG_Din_int)
);
endmodule // boot_cpld
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