/*
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/*
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Asynchronous SDM NoC
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Asynchronous SDM NoC
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(C)2011 Wei Song
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(C)2011 Wei Song
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Advanced Processor Technologies Group
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Advanced Processor Technologies Group
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Computer Science, the Univ. of Manchester, UK
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Computer Science, the Univ. of Manchester, UK
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Authors:
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Authors:
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Wei Song wsong83@gmail.com
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Wei Song wsong83@gmail.com
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License: LGPL 3.0 or later
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License: LGPL 3.0 or later
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Sub-channel controller
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Sub-channel controller
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References
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References
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* Lookahead pipelines
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* Lookahead pipelines
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Montek Singh and Steven M. Nowick, The design of high-performance dynamic asynchronous pipelines: lookahead style, IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 2007(15), 1256-1269. doi:10.1109/TVLSI.2007.902205
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Montek Singh and Steven M. Nowick, The design of high-performance dynamic asynchronous pipelines: lookahead style, IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 2007(15), 1256-1269. doi:10.1109/TVLSI.2007.902205
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* Channel slicing
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* Channel slicing
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Wei Song and Doug Edwards, A low latency wormhole router for asynchronous on-chip networks, Asia and South Pacific Design Automation Conference, 2010, 437-443.
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Wei Song and Doug Edwards, A low latency wormhole router for asynchronous on-chip networks, Asia and South Pacific Design Automation Conference, 2010, 437-443.
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For the detail structure, please refer to Section 7.1.1 of the thesis:
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For the detail structure, please refer to Section 7.1.1 of the thesis:
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Wei Song, Spatial parallelism in the routers of asynchronous on-chip networks, PhD thesis, the University of Manchester, 2011.
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Wei Song, Spatial parallelism in the routers of asynchronous on-chip networks, PhD thesis, the University of Manchester, 2011.
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History:
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History:
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05/05/2009 Initial version. <wsong83@gmail.com>
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05/05/2009 Initial version. <wsong83@gmail.com>
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22/10/2010 Make it more timing robust. <wsong83@gmail.com>
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22/10/2010 Make it more timing robust. <wsong83@gmail.com>
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24/05/2011 Clean up for opensource. <wsong83@gmail.com>
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24/05/2011 Clean up for opensource. <wsong83@gmail.com>
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*/
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*/
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// the router structure definitions
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// the router structure definitions
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`include "define.v"
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`include "define.v"
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module subc_ctl (/*AUTOARG*/
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module subc_ctl (/*AUTOARG*/
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// Outputs
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// Outputs
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nack, rt_rst,
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nack, rt_rst,
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// Inputs
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// Inputs
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ai2cb, ack, eof, rt_ra, rt_err, rst_n
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ai2cb, ack, eof, rt_ra, rt_err, rst_n
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);
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);
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input ai2cb; // the ack from output ports
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input ai2cb; // the ack from output ports
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input ack; // the ack from the last stage of the input buffer
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input ack; // the ack from the last stage of the input buffer
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input eof; // the eof bit from the last stage of the input buffer
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input eof; // the eof bit from the last stage of the input buffer
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input rt_ra; // ack from the switch allocator
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input rt_ra; // ack from the switch allocator
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input rt_err; // invalid router decision
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input rt_err; // invalid router decision
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input rst_n; // the global active low reset signal
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input rst_n; // the global active low reset signal
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output nack; // the ack to the last stage of the input buffer
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output nack; // the ack to the last stage of the input buffer
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output rt_rst; // the router reset signal
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output rt_rst; // the router reset signal
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wire csc; // internal wires to handle the CSC of the STG
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wire csc; // internal wires to handle the CSC of the STG
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wire acko; // the ack signal after the C2N gate
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wire acko; // the ack signal after the C2N gate
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wire fend; // the end of frame indicator
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wire fend; // the end of frame indicator
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wire acken; // active low ack enable
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wire acken; // active low ack enable
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`ifdef ENABLE_LOOKAHEAD
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`ifdef ENABLE_LOOKAHEAD
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c2n CD (.q(acko), .a0(ai2cb), .a1(ack)); // the C2N gate to avoid early withdrawal
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c2n CD (.q(acko), .a0(ai2cb), .a1(ack)); // the C2N gate to avoid early withdrawal
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`else
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`else
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assign acko = ai2cb;
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assign acko = ai2cb;
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`endif
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`endif
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c2p CEN (.a1(eof), .a0(acko), .q(fend));
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c2p CEN (.a1(eof), .a0(acko), .q(fend));
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c2 C (.a0(rt_ra), .a1(fend), .q(csc));
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c2 C (.a0(rt_ra), .a1(fend), .q(csc));
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nand U1 ( acken, rt_ra, ~csc);
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nand U1 ( acken, rt_ra, ~csc);
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nor U2 ( rt_rst, fend, ~csc);
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nor U2 ( rt_rst, fend, ~csc);
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nor AG ( nack, acko&(~eof), acken|(rt_err&ack), ~rst_n);
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nor AG ( nack, acko&(~eof), acken|(rt_err&ack), ~rst_n);
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endmodule // subc_ctl
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endmodule // subc_ctl
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