mirror of https://github.com/lnis-uofu/SOFA.git
71 lines
2.6 KiB
Verilog
71 lines
2.6 KiB
Verilog
`timescale 1ns/1ps
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//-----------------------------------------------------
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// Function : An embedded I/O with
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// - An I/O isolation signal to set
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// the I/O in input mode. This is to avoid
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// any unexpected output signals to damage
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// circuits outside the FPGA due to configurable
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// memories are not properly initialized
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// This feature may not be needed if the configurable
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// memory cell has a built-in set/reset functionality
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// - Internal protection circuitry to ensure
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// clean signals at all the SOC I/O ports
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// This is to avoid
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// - output any random signal
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// when the I/O is in input mode, also avoid
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// - driven by any random signal
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// when the I/O is output mode
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//
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// Note: This cell is built with Standard Cells from HD library
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// It is already technology mapped and can be directly used
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// for physical design
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//-----------------------------------------------------
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module IO (
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input SOC_IN, // Input to drive the inpad signal
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output SOC_OUT, // Output the outpad signal
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output FPGA_IN, // Input data to FPGA
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input FPGA_OUT, // Output data from FPGA
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input FPGA_IO_DIR,
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input CFG_DONE,
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input IO_ISOL_N
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);
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wire cfg_done_b;
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wire io_isol;
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wire f2a_o_gate;
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wire f2a_o_int;
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sky130_fd_sc_hd__inv_1 INV_CFG_DONE (
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.A(CFG_DONE),
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.Y(cfg_done_b)
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);
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sky130_fd_sc_hd__inv_1 INV_ISOL_N (
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.A(IO_ISOL_N),
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.Y(io_isol)
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);
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// output path
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sky130_fd_sc_hd__nor2_1 NOR2 (
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.A(FPGA_IO_DIR),
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.B(cfg_done_b),
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.Y(f2a_o_gate)
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);
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sky130_fd_sc_hd__nand2_1 NAND2 (
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.A(FPGA_OUT),
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.B(f2a_o_gate),
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.Y(f2a_o_int)
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);
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sky130_fd_sc_hd__einvn_4 EINVN_OUT (
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.A(f2a_o_int),
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.TE_B(io_isol),
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.Z(SOC_OUT)
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);
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// input path
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sky130_fd_sc_hd__and3_1 AND3 (
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.A(SOC_IN),
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.B(FPGA_IO_DIR),
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.C(IO_ISOL_N),
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.X(FPGA_IN)
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);
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endmodule
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