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[/] [usbhostslave/] [trunk/] [RTL/] [serialInterfaceEngine/] [processRxBit.v] - Rev 2
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//-------------------------------------------------------------------------------------------------- // // Title : No Title // Design : usbhostslave // Author : Steve // Company : Base2Designs // //------------------------------------------------------------------------------------------------- // // File : c:\projects\USBHostSlave\Aldec\usbhostslave\usbhostslave\compile\processRxBit.v // Generated : 09/12/04 22:54:47 // From : c:\projects\USBHostSlave\RTL\serialInterfaceEngine\processRxBit.asf // By : FSM2VHDL ver. 4.0.3.8 // //------------------------------------------------------------------------------------------------- // // Description : // //------------------------------------------------------------------------------------------------- `timescale 1ns / 1ps `include "usbSerialInterfaceEngine_h.v" module processRxBit (JBit, KBit, RxBitsIn, RxCtrlOut, RxDataOut, clk, processRxBitRdy, processRxBitsWEn, processRxByteRdy, processRxByteWEn, resumeDetected, rst); input [1:0] JBit; input [1:0] KBit; input [1:0] RxBitsIn; input clk; input processRxBitsWEn; input processRxByteRdy; input rst; output [7:0] RxCtrlOut; output [7:0] RxDataOut; output processRxBitRdy; output processRxByteWEn; output resumeDetected; wire [1:0] JBit; wire [1:0] KBit; wire [1:0] RxBitsIn; reg [7:0] RxCtrlOut, next_RxCtrlOut; reg [7:0] RxDataOut, next_RxDataOut; wire clk; reg processRxBitRdy, next_processRxBitRdy; wire processRxBitsWEn; wire processRxByteRdy; reg processRxByteWEn, next_processRxByteWEn; reg resumeDetected, next_resumeDetected; wire rst; // diagram signals declarations reg [3:0]RXBitCount, next_RXBitCount; reg [1:0]RXBitStMachCurrState, next_RXBitStMachCurrState; reg [7:0]RXByte, next_RXByte; reg [3:0]RXSameBitCount, next_RXSameBitCount; reg [1:0]RxBits, next_RxBits; reg bitStuffError, next_bitStuffError; reg [1:0]oldRXBits, next_oldRXBits; reg [3:0]resumeWaitCnt, next_resumeWaitCnt; // BINARY ENCODED state machine: prRxBit // State codes definitions: `define START 4'b0000 `define IDLE_FIRST_BIT 4'b0001 `define WAIT_BITS 4'b0010 `define IDLE_CHK_KBIT 4'b0011 `define DATA_RX_LAST_BIT 4'b0100 `define DATA_RX_CHK_SE0 4'b0101 `define DATA_RX_DATA_DESTUFF 4'b0110 `define DATA_RX_BYTE_SEND2 4'b0111 `define DATA_RX_BYTE_WAIT_RDY 4'b1000 `define RES_RX_CHK 4'b1001 `define DATA_RX_ERROR_CHK_RES 4'b1010 `define RES_END_CHK1 4'b1011 `define IDLE_WAIT_PRB_RDY 4'b1100 `define DATA_RX_WAIT_PRB_RDY 4'b1101 `define DATA_RX_ERROR_WAIT_RDY 4'b1110 reg [3:0] CurrState_prRxBit; reg [3:0] NextState_prRxBit; //-------------------------------------------------------------------- // Machine: prRxBit //-------------------------------------------------------------------- //---------------------------------- // NextState logic (combinatorial) //---------------------------------- always @ (RxBitsIn or RxBits or oldRXBits or RXSameBitCount or RXBitCount or RXByte or JBit or KBit or resumeWaitCnt or processRxBitsWEn or RXBitStMachCurrState or processRxByteRdy or bitStuffError or processRxByteWEn or RxCtrlOut or RxDataOut or resumeDetected or processRxBitRdy or CurrState_prRxBit) begin : prRxBit_NextState NextState_prRxBit <= CurrState_prRxBit; // Set default values for outputs and signals next_processRxByteWEn <= processRxByteWEn; next_RxCtrlOut <= RxCtrlOut; next_RxDataOut <= RxDataOut; next_resumeDetected <= resumeDetected; next_RXBitStMachCurrState <= RXBitStMachCurrState; next_RxBits <= RxBits; next_RXSameBitCount <= RXSameBitCount; next_RXBitCount <= RXBitCount; next_oldRXBits <= oldRXBits; next_RXByte <= RXByte; next_bitStuffError <= bitStuffError; next_resumeWaitCnt <= resumeWaitCnt; next_processRxBitRdy <= processRxBitRdy; case (CurrState_prRxBit) // synopsys parallel_case full_case `START: begin next_processRxByteWEn <= 1'b0; next_RxCtrlOut <= 8'h00; next_RxDataOut <= 8'h00; next_resumeDetected <= 1'b0; next_RXBitStMachCurrState <= `IDLE_BIT_ST; next_RxBits <= 2'b00; next_RXSameBitCount <= 4'h0; next_RXBitCount <= 4'h0; next_oldRXBits <= 2'b00; next_RXByte <= 8'h00; next_bitStuffError <= 1'b0; next_resumeWaitCnt <= 4'h0; next_processRxBitRdy <= 1'b1; NextState_prRxBit <= `WAIT_BITS; end `WAIT_BITS: if ((processRxBitsWEn == 1'b1) && (RXBitStMachCurrState == `DATA_RECEIVE_BIT_ST)) begin NextState_prRxBit <= `DATA_RX_CHK_SE0; next_RxBits <= RxBitsIn; next_processRxBitRdy <= 1'b0; end else if ((processRxBitsWEn == 1'b1) && (RXBitStMachCurrState == `WAIT_RESUME_ST)) begin NextState_prRxBit <= `RES_RX_CHK; next_RxBits <= RxBitsIn; next_processRxBitRdy <= 1'b0; end else if ((processRxBitsWEn == 1'b1) && (RXBitStMachCurrState == `RESUME_END_WAIT_ST)) begin NextState_prRxBit <= `RES_END_CHK1; next_RxBits <= RxBitsIn; next_processRxBitRdy <= 1'b0; end else if ((processRxBitsWEn == 1'b1) && (RXBitStMachCurrState == `IDLE_BIT_ST)) begin NextState_prRxBit <= `IDLE_CHK_KBIT; next_RxBits <= RxBitsIn; next_processRxBitRdy <= 1'b0; end `IDLE_FIRST_BIT: begin next_processRxByteWEn <= 1'b0; next_RXBitStMachCurrState <= `DATA_RECEIVE_BIT_ST; next_RXSameBitCount <= 4'h1; next_RXBitCount <= 4'h1; next_oldRXBits <= RxBits; //zero is always the first RZ data bit of a new packet next_RXByte <= 8'h00; NextState_prRxBit <= `WAIT_BITS; next_processRxBitRdy <= 1'b1; end `IDLE_CHK_KBIT: if (RxBits == KBit) NextState_prRxBit <= `IDLE_WAIT_PRB_RDY; else begin NextState_prRxBit <= `WAIT_BITS; next_processRxBitRdy <= 1'b1; end `IDLE_WAIT_PRB_RDY: if (processRxByteRdy == 1'b1) begin NextState_prRxBit <= `IDLE_FIRST_BIT; next_RxDataOut <= 8'h00; //redundant data next_RxCtrlOut <= `DATA_START; //start of packet next_processRxByteWEn <= 1'b1; end `DATA_RX_LAST_BIT: begin next_processRxByteWEn <= 1'b0; next_RXBitStMachCurrState <= `IDLE_BIT_ST; NextState_prRxBit <= `WAIT_BITS; next_processRxBitRdy <= 1'b1; end `DATA_RX_CHK_SE0: begin next_bitStuffError <= 1'b0; if (RxBits == `SE0) NextState_prRxBit <= `DATA_RX_WAIT_PRB_RDY; else begin NextState_prRxBit <= `DATA_RX_DATA_DESTUFF; if (RxBits == oldRXBits) //if the current 'RxBits' are the same as the old 'RxBits', then begin next_RXSameBitCount <= RXSameBitCount + 1'b1; //inc 'RXSameBitCount' if (RXSameBitCount == `MAX_CONSEC_SAME_BITS) //if 'RXSameBitCount' == 7 there has been a bit stuff error next_bitStuffError <= 1'b1; //flag 'bitStuffError' else //else no bit stuffing error begin next_RXBitCount <= RXBitCount + 1'b1; if (RXBitCount != 4'h7) begin next_processRxBitRdy <= 1'b1; //early indication of ready end next_RXByte <= { 1'b1, RXByte[7:1]}; //RZ bit = 1 (ie no change in 'RxBits') end end else //else current 'RxBits' are different from old 'RxBits' begin if (RXSameBitCount != `MAX_CONSEC_SAME_BITS) //if this is not the RZ 0 bit after 6 consecutive RZ 1s, then begin next_RXBitCount <= RXBitCount + 1'b1; if (RXBitCount != 4'h7) begin next_processRxBitRdy <= 1'b1; //early indication of ready end next_RXByte <= {1'b0, RXByte[7:1]}; //RZ bit = 0 (ie current'RxBits' is different than old 'RxBits') end next_RXSameBitCount <= 4'h1; //reset 'RXSameBitCount' end next_oldRXBits <= RxBits; end end `DATA_RX_WAIT_PRB_RDY: if (processRxByteRdy == 1'b1) begin NextState_prRxBit <= `DATA_RX_LAST_BIT; next_RxDataOut <= 8'h00; //redundant data next_RxCtrlOut <= `DATA_STOP; //end of packet next_processRxByteWEn <= 1'b1; end `DATA_RX_DATA_DESTUFF: if (RXBitCount == 4'h8 & bitStuffError == 1'b0) NextState_prRxBit <= `DATA_RX_BYTE_WAIT_RDY; else if (bitStuffError == 1'b1) NextState_prRxBit <= `DATA_RX_ERROR_WAIT_RDY; else begin NextState_prRxBit <= `WAIT_BITS; next_processRxBitRdy <= 1'b1; end `DATA_RX_BYTE_SEND2: begin next_processRxByteWEn <= 1'b0; NextState_prRxBit <= `WAIT_BITS; next_processRxBitRdy <= 1'b1; end `DATA_RX_BYTE_WAIT_RDY: if (processRxByteRdy == 1'b1) begin NextState_prRxBit <= `DATA_RX_BYTE_SEND2; next_RXBitCount <= 4'h0; next_RxDataOut <= RXByte; next_RxCtrlOut <= `DATA_STREAM; next_processRxByteWEn <= 1'b1; end `DATA_RX_ERROR_CHK_RES: begin next_processRxByteWEn <= 1'b0; if (RxBits == JBit) //if current bit is a JBit, then next_RXBitStMachCurrState <= `IDLE_BIT_ST; //next state is idle else //else begin next_RXBitStMachCurrState <= `WAIT_RESUME_ST; //check for resume next_resumeWaitCnt <= 0; end NextState_prRxBit <= `WAIT_BITS; next_processRxBitRdy <= 1'b1; end `DATA_RX_ERROR_WAIT_RDY: if (processRxByteRdy == 1'b1) begin NextState_prRxBit <= `DATA_RX_ERROR_CHK_RES; next_RxDataOut <= 8'h00; //redundant data next_RxCtrlOut <= `DATA_BIT_STUFF_ERROR; next_processRxByteWEn <= 1'b1; end `RES_RX_CHK: begin if (RxBits != KBit) //can only be a resume if line remains in Kbit state next_RXBitStMachCurrState <= `IDLE_BIT_ST; else begin next_resumeWaitCnt <= resumeWaitCnt + 1'b1; //if we've waited long enough, then if (resumeWaitCnt == `RESUME_WAIT_TIME_MINUS1) begin next_RXBitStMachCurrState <= `RESUME_END_WAIT_ST; next_resumeDetected <= 1'b1; //report resume detected end end NextState_prRxBit <= `WAIT_BITS; next_processRxBitRdy <= 1'b1; end `RES_END_CHK1: begin if (RxBits != KBit) //line must leave KBit state for the end of resume begin next_RXBitStMachCurrState <= `IDLE_BIT_ST; next_resumeDetected <= 1'b0; //clear resume detected flag end NextState_prRxBit <= `WAIT_BITS; next_processRxBitRdy <= 1'b1; end endcase end //---------------------------------- // Current State Logic (sequential) //---------------------------------- always @ (posedge clk) begin : prRxBit_CurrentState if (rst) CurrState_prRxBit <= `START; else CurrState_prRxBit <= NextState_prRxBit; end //---------------------------------- // Registered outputs logic //---------------------------------- always @ (posedge clk) begin : prRxBit_RegOutput if (rst) begin RXBitStMachCurrState <= `IDLE_BIT_ST; RxBits <= 2'b00; RXSameBitCount <= 4'h0; RXBitCount <= 4'h0; oldRXBits <= 2'b00; RXByte <= 8'h00; bitStuffError <= 1'b0; resumeWaitCnt <= 4'h0; processRxByteWEn <= 1'b0; RxCtrlOut <= 8'h00; RxDataOut <= 8'h00; resumeDetected <= 1'b0; processRxBitRdy <= 1'b1; end else begin RXBitStMachCurrState <= next_RXBitStMachCurrState; RxBits <= next_RxBits; RXSameBitCount <= next_RXSameBitCount; RXBitCount <= next_RXBitCount; oldRXBits <= next_oldRXBits; RXByte <= next_RXByte; bitStuffError <= next_bitStuffError; resumeWaitCnt <= next_resumeWaitCnt; processRxByteWEn <= next_processRxByteWEn; RxCtrlOut <= next_RxCtrlOut; RxDataOut <= next_RxDataOut; resumeDetected <= next_resumeDetected; processRxBitRdy <= next_processRxBitRdy; end end endmodule
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