1 | //-------------------------------------------------------------------------- |
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2 | // -- |
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3 | // OneWireMaster -- |
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4 | // A synthesizable 1-wire master peripheral -- |
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5 | // Copyright 1999-2005 Dallas Semiconductor Corporation -- |
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6 | // -- |
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7 | //-------------------------------------------------------------------------- |
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8 | // -- |
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9 | // Purpose: Provides timing and control of Dallas 1-wire bus -- |
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10 | // through a memory-mapped peripheral -- |
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11 | // File: one_wire_interface.v -- |
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12 | // Date: February 1, 2005 -- |
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13 | // Version: v2.100 -- |
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14 | // Authors: Rick Downs and Charles Hill, -- |
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15 | // Dallas Semiconductor Corporation -- |
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16 | // -- |
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17 | // Note: This source code is available for use without license. -- |
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18 | // Dallas Semiconductor is not responsible for the -- |
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19 | // functionality or utility of this product. -- |
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20 | // -- |
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21 | // REV: Added BIT_CTL to COMMAND reg - GAG -- |
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22 | // Added STPEN to COMMAND reg - GAG -- |
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23 | // Combined CLK_DIV register bits into one block - GAG -- |
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24 | // Added CLK_EN to CLK_DIV reg - GAG -- |
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25 | // Added CONTROL reg and moved appropriate bits into it - GAG -- |
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26 | // Added EN_FOW and changed dqz to FOW - GAG -- |
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27 | // Added STP_SPLY - GAG -- |
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28 | // Significant changes to improve synthesis - English -- |
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29 | // Ported to Verilog - Sandelin -- |
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30 | //-------------------------------------------------------------------------- |
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31 | |
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32 | module one_wire_interface ( |
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33 | ADDRESS, ADS_bar, clear_interrupts, DIN, DQ_IN, EN_bar, FSM_CLK, MR, |
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34 | OneWireIO_eq_Load, pdr, OW_LOW, OW_SHORT, rbf, |
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35 | rcvr_buffer, RD_bar, reset_owr, rsrf, temt, WR_bar, BIT_CTL, |
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36 | CLK_EN, clr_activate_intr, DDIR, div_1, div_2, div_3, DOUT, EN_FOW, EOWL, |
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37 | EOWSH, epd, erbf, ersf, etbe, etmt, FOW, ias, |
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38 | LLM, OD, owr, pd, PPM, pre_0, pre_1, rbf_reset, sr_a, STP_SPLY, STPEN, tbe, |
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39 | xmit_buffer,dq_sel); |
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40 | |
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41 | input [2:0] ADDRESS; |
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42 | input ADS_bar; |
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43 | input clear_interrupts; |
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44 | input [7:0] DIN; |
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45 | input DQ_IN; |
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46 | input EN_bar; |
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47 | input FSM_CLK; |
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48 | input MR; |
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49 | input OneWireIO_eq_Load; |
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50 | input pdr; |
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51 | input OW_LOW; // ow bus low interrupt |
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52 | input OW_SHORT; // ow bus shorted interrupt |
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53 | input rbf; // receive buffer full int |
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54 | input [7:0] rcvr_buffer; |
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55 | input RD_bar; |
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56 | input reset_owr; |
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57 | input rsrf; // receive shift reg full int |
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58 | input temt; |
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59 | input WR_bar; |
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60 | |
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61 | output BIT_CTL; // enable signle bit outputs |
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62 | output CLK_EN; // clock divider enable |
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63 | output clr_activate_intr; |
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64 | output DDIR; |
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65 | output div_1; // divider select bit 1 |
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66 | output div_2; // divider select bit 2 |
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67 | output div_3; // divider select bit 3 |
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68 | output [7:0] DOUT; |
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69 | output EN_FOW; // enable force OW functionality |
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70 | output EOWL; // enable one wire bus low interrupt |
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71 | output EOWSH; // enable one wire short interrupt |
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72 | output epd; // enable presence detect interrupt |
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73 | output erbf; // enable receive buffer full interrupt |
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74 | output ersf; // enable receive shift register full int. |
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75 | output etbe; // enable transmit buffer empty interrupt |
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76 | output etmt; // enable transmit shift outputister empty int. |
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77 | output FOW; // force OW value to opposite value |
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78 | output ias; // INTR active state |
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79 | output LLM; // long line mode enable |
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80 | output OD; // enable overdrive |
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81 | output owr; |
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82 | output pd; |
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83 | output PPM; // presence pulse masking enable |
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84 | output pre_0; // prescaler select bit 0 |
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85 | output pre_1; // prescaler select bit 1 |
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86 | output rbf_reset; // clear signal for rbf |
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87 | output sr_a; |
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88 | output STP_SPLY; // enable strong pull up supply mode |
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89 | output STPEN; // enable strong pull up output |
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90 | output tbe; |
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91 | output [7:0] xmit_buffer; |
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92 | output [2:0] dq_sel; |
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93 | reg [2:0] dq_sel; |
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94 | |
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95 | |
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96 | wire read_op; |
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97 | wire write_op; |
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98 | reg [2:0] sel_addr; // selected register address |
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99 | |
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100 | // command register |
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101 | reg sr_a; // search ROM accelerator command |
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102 | reg owr; // 1W reset command |
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103 | reg FOW; // Force OW value |
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104 | wire [7:0] CMD_REG = {4'b0, DQ_IN, FOW, sr_a, owr}; |
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105 | |
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106 | reg set_activate_intr; |
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107 | reg clr_activate_intr; |
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108 | reg xmit_buffer_full; |
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109 | |
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110 | reg [7:0] xmit_buffer; // transmit buffer |
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111 | |
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112 | // Control register |
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113 | reg OD; // enable overdrive |
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114 | reg BIT_CTL; // enable single bit transmitions |
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115 | reg STP_SPLY; // Strong Pullup supply mode enable |
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116 | reg STPEN; // enable strong pull up output |
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117 | reg EN_FOW; // enable force OW functionality |
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118 | reg PPM; // Presence Pulse masking enable |
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119 | reg LLM; // Long Line mode enable (stretch timing) |
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120 | wire [7:0] CONTRL_REG = {1'b0, OD, BIT_CTL, STP_SPLY, STPEN, EN_FOW, |
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121 | PPM, LLM}; |
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122 | |
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123 | // interrupt register |
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124 | wire OW_LOW; // OW low interrupt |
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125 | wire OW_SHORT; // OW shorted interrupt |
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126 | reg pd; // presence detect done flag |
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127 | wire pdr; // presence detect result |
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128 | reg tbe; // transmit buffer empty flag |
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129 | wire rbf; // receive buffer full flag |
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130 | wire [7:0] INT_REG = {OW_LOW, OW_SHORT, rsrf, rbf, temt, tbe, pdr, pd}; |
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131 | |
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132 | // interrupt enable register |
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133 | reg EOWL; // enable OW low interrupt |
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134 | reg EOWSH; // enable OW shorted interrupt |
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135 | reg epd; // enable presence detect interrupt |
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136 | reg ias; // INTR active state |
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137 | reg etbe; // enable transmit buffer empty interrupt |
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138 | reg etmt; // enable transmit shift register empty int. |
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139 | reg erbf; // enable receive buffer full interrupt |
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140 | reg ersf; // enable receive shift register full int. |
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141 | wire [7:0] INTEN_REG = {EOWL, EOWSH, ersf, erbf, etmt, etbe, ias, epd}; |
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142 | |
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143 | // clock divisor register |
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144 | reg pre_0; // prescaler select bit 0 |
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145 | reg pre_1; // prescaler select bit 1 |
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146 | reg div_1; // divider select bit 1 |
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147 | reg div_2; // divider select bit 2 |
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148 | reg div_3; // divider select bit 3 |
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149 | reg CLK_EN; // clock divider enable |
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150 | wire [7:0] CLKDV_REG = {CLK_EN, 2'b0, div_3, div_2, div_1, pre_1, pre_0}; |
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151 | |
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152 | |
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153 | |
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154 | //-------------------------------------------------------------------------- |
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155 | // read/write process |
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156 | //-------------------------------------------------------------------------- |
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157 | |
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158 | assign read_op = ~EN_bar && ~MR && ~RD_bar && WR_bar; |
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159 | wire read_op_n=~read_op; |
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160 | |
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161 | assign write_op = ~EN_bar && ~MR && ~WR_bar && RD_bar; |
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162 | wire write_op_n = ~write_op; |
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163 | |
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164 | always @(posedge MR or posedge WR_bar) |
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165 | if(MR) // removed reset interrupt reg when chip not enabled |
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166 | begin |
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167 | EOWL = 1'b0; |
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168 | EOWSH = 1'b0; |
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169 | ersf = 1'b0; |
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170 | erbf = 1'b0; |
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171 | etmt = 1'b0; |
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172 | etbe = 1'b0; |
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173 | ias = 1'b0; |
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174 | epd = 1'b0; |
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175 | xmit_buffer=0; |
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176 | end |
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177 | else |
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178 | if(!EN_bar && RD_bar) |
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179 | case(sel_addr) |
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180 | 3'b001: |
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181 | xmit_buffer = DIN; |
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182 | 3'b011: //removed ias to hard wire active low - GAG |
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183 | //added ias to remove hardwire - SKH |
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184 | begin |
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185 | EOWL = DIN[7]; |
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186 | EOWSH = DIN[6]; |
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187 | ersf = DIN[5]; |
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188 | erbf = DIN[4]; |
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189 | etmt = DIN[3]; |
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190 | etbe = DIN[2]; |
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191 | ias = DIN[1]; |
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192 | epd = DIN[0]; |
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193 | end |
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194 | endcase |
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195 | |
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196 | assign DDIR = read_op; |
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197 | |
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198 | // |
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199 | // Modified DOUT to always drive the current register value out |
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200 | // based on the address value |
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201 | // |
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202 | assign DOUT = |
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203 | (sel_addr == 3'b000)?{1'b0,dq_sel [2:0],DQ_IN,FOW,sr_a,owr}: |
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204 | (sel_addr == 3'b001)?rcvr_buffer: |
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205 | (sel_addr == 3'b010)?{OW_LOW,OW_SHORT,rsrf,rbf,temt,tbe,pdr,pd}: |
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206 | (sel_addr == 3'b011)?{EOWL,EOWSH,ersf,erbf,etmt,etbe,ias,epd}: |
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207 | (sel_addr == 3'b100)?{CLK_EN,2'b00,div_3,div_2,div_1,pre_1,pre_0}: |
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208 | (sel_addr == 3'b101)?{1'b0,OD,BIT_CTL,STP_SPLY,STPEN,EN_FOW,PPM,LLM}: |
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209 | 8'h00; |
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210 | |
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211 | |
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212 | // |
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213 | // Clock divisor register |
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214 | // |
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215 | // synopsys async_set_reset MR |
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216 | always @(posedge MR or posedge WR_bar) |
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217 | if(MR) |
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218 | begin |
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219 | pre_0 = 1'b0; |
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220 | pre_1 = 1'b0; |
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221 | div_1 = 1'b0; |
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222 | div_2 = 1'b0; |
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223 | div_3 = 1'b0; |
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224 | CLK_EN = 1'b0; |
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225 | end |
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226 | else |
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227 | if(!EN_bar && RD_bar) |
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228 | if(sel_addr == 3'b100) |
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229 | begin |
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230 | pre_0 = DIN[0]; |
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231 | pre_1 = DIN[1]; |
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232 | div_1 = DIN[2]; |
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233 | div_2 = DIN[3]; |
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234 | div_3 = DIN[4]; |
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235 | CLK_EN = DIN[7]; |
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236 | end |
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237 | |
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238 | |
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239 | wire CLR_OWR = MR || reset_owr; |
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240 | |
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241 | // |
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242 | // Command reg writes are handled in the next two sections |
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243 | // Bit 0 needs to be separate for the added clearing mechanism |
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244 | // |
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245 | always @(posedge CLR_OWR or posedge WR_bar) |
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246 | if(CLR_OWR) |
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247 | begin |
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248 | owr <= 1'b0; |
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249 | end |
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250 | else |
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251 | begin |
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252 | if(EN_bar == 0 && RD_bar == 1) |
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253 | if(sel_addr == 3'b000) |
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254 | owr <= DIN[0]; |
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255 | end |
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256 | // |
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257 | // Bits 1-7's write routine |
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258 | // |
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259 | always @(posedge MR or posedge WR_bar) |
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260 | if(MR) |
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261 | begin |
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262 | FOW <= 1'b0; |
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263 | sr_a <= 1'b0; |
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264 | dq_sel [2:0] <= 3'b000; |
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265 | end |
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266 | else |
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267 | begin |
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268 | if(EN_bar == 0 && RD_bar == 1) |
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269 | if(sel_addr == 3'b000) |
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270 | begin |
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271 | sr_a <= DIN[1]; |
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272 | FOW <= DIN[2]; |
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273 | dq_sel [2:0] <= DIN[6:4]; |
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274 | end |
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275 | end |
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276 | |
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277 | // |
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278 | // The Control reg writes are handled here |
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279 | // |
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280 | always @(posedge MR or posedge WR_bar) |
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281 | if(MR) |
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282 | begin |
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283 | OD <= 1'b0; |
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284 | BIT_CTL <= 1'b0; |
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285 | STP_SPLY<= 1'b0; |
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286 | STPEN <= 1'b0; |
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287 | EN_FOW <= 1'b0; |
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288 | PPM <= 1'b0; |
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289 | LLM <= 1'b0; |
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290 | end |
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291 | else |
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292 | begin |
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293 | if(EN_bar == 0 && RD_bar == 1) |
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294 | if(sel_addr == 3'b101) |
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295 | begin |
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296 | OD <= DIN[6]; |
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297 | BIT_CTL <= DIN[5]; |
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298 | STP_SPLY<= DIN[4]; |
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299 | STPEN <= DIN[3]; |
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300 | EN_FOW <= DIN[2]; |
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301 | PPM <= DIN[1]; |
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302 | LLM <= DIN[0]; |
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303 | end |
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304 | end |
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305 | |
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306 | |
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307 | //-------------------------------------------------------------------------- |
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308 | // Transparent address latch |
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309 | //-------------------------------------------------------------------------- |
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310 | |
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311 | always @(ADS_bar or ADDRESS or EN_bar) |
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312 | if(!ADS_bar && !EN_bar) |
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313 | sel_addr = ADDRESS; |
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314 | |
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315 | //-------------------------------------------------------------------------- |
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316 | // Interrupt flag register clearing (What is not handled in onewiremaster.v) |
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317 | //-------------------------------------------------------------------------- |
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318 | |
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319 | wire acint_reset = MR || (clear_interrupts); // synchronized |
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320 | // set_activate_intr - SDS |
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321 | |
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322 | always @(posedge acint_reset or posedge RD_bar) |
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323 | if(acint_reset) |
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324 | clr_activate_intr <= 1'b0; |
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325 | else |
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326 | if(EN_bar == 0 && WR_bar == 1) |
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327 | if(sel_addr == 3'b010) |
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328 | clr_activate_intr <= 1'b1; |
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329 | |
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330 | wire rbf_reset = (read_op && (sel_addr == 3'b001)); |
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331 | |
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332 | always @(posedge MR or posedge FSM_CLK) |
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333 | if (MR) |
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334 | pd <= 1'b0; |
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335 | else if (reset_owr) |
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336 | pd <= 1'b1; |
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337 | else if (clr_activate_intr) // This causes pd to wait for a clk to clear |
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338 | pd <= 1'b0; |
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339 | else |
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340 | pd <= pd; |
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341 | |
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342 | // |
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343 | // The following two blocks handle tbe |
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344 | // The lower is the psuedo asynch portion which is synched up |
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345 | // in the upper section. |
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346 | // |
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347 | always @(posedge FSM_CLK or posedge MR) |
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348 | if (MR) |
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349 | tbe <= 1'b1; |
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350 | else |
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351 | tbe <= ~xmit_buffer_full; |
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352 | |
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353 | always @(posedge MR or posedge WR_bar or posedge OneWireIO_eq_Load) |
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354 | if(MR) |
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355 | xmit_buffer_full <= 1'b0; |
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356 | else if (OneWireIO_eq_Load) |
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357 | xmit_buffer_full <= 1'b0; |
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358 | else |
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359 | if(EN_bar == 0 && RD_bar == 1) |
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360 | if(sel_addr == 3'b001) |
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361 | xmit_buffer_full <= 1'b1; |
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362 | |
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363 | endmodule // one_wire_interface |
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364 | |
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