1 | function [backoff_start, phy_tx_start, tx_done, tx_result_out, fsm_state_out] = ... |
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2 | mac_tx_ctrl_a_fsm(... |
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3 | pre_wait_postRxTimer1, ... |
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4 | pre_wait_postTxTimer1, ... |
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5 | post_wait_postTxTimer2, ... |
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6 | reset, ... |
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7 | new_tx, ... |
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8 | postRxTimer1_done, ... |
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9 | postTxTimer1_done, ... |
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10 | postTxTimer2_done, ... |
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11 | backoff_done, ... |
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12 | idle_for_difs, ... |
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13 | phy_tx_done, ... |
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14 | phy_rx_start) |
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15 | |
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16 | persistent fsm_state, fsm_state=xl_state(0, {xlUnsigned, 3, 0}); |
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17 | persistent tx_result, tx_result=xl_state(0, {xlUnsigned, 2, 0}); |
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18 | |
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19 | fsm_state_out = fsm_state; |
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20 | tx_result_out = tx_result; |
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21 | |
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22 | %Inputs: |
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23 | % reset: synchronous reset, forces internal state variables back to default (IDLE state) |
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24 | % new_tx: Software request for new Tx cycle |
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25 | % pre_wait_postRxTimer1: Param requiring this Tx occur after postRxTimer 1 expires |
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26 | % pre_wait_postTxTimer1: Param requiring this Tx occur after postTxTimer 1 expires |
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27 | % post_wait_postTxTimer2: Param requiring this Tx state wait after transmitting for postTxTimer 2 expiration |
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28 | % backoff_done: Indication from MAC hw that backoff period is done |
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29 | % idle_for_difs: Indication from MAC hw that medium has been idle > DIFS/EIFS |
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30 | % phy_tx_done: Indication from PHY that last sample is transmitted |
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31 | % phy_rx_start: Indication from PHY that new Rx has started |
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32 | |
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33 | %Outputs: |
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34 | % backoff_start: Indication to MAC hw to run idle->backoff process |
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35 | % phy_tx_start: Indication to PHY to start Tx |
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36 | % tx_done: Indication to MAC hw that this Tx cycle is complete |
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37 | % tx_result_out: Status of tx_done (timeout or rx_started) |
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38 | % fsm_state_out: Value of internal state register (for debugging) |
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39 | |
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40 | ST_IDLE = 0; |
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41 | ST_PRE_TX_WAIT = 1; |
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42 | ST_START_BO = 2; |
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43 | ST_DEFER = 3; |
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44 | ST_DO_TX = 4; |
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45 | ST_POST_TX = 5; |
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46 | ST_POST_TX_WAIT = 6; |
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47 | ST_DONE = 7; |
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48 | |
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49 | TX_RESULT_NONE = 0; |
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50 | TX_RESULT_POSTTX_TIMER_EXPIRED = 1; |
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51 | TX_RESULT_RX_STARTED = 2; |
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52 | |
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53 | if(reset) |
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54 | backoff_start = 0; |
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55 | phy_tx_start = 0; |
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56 | tx_done = 0; |
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57 | fsm_state = ST_IDLE; |
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58 | tx_result = TX_RESULT_NONE; |
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59 | |
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60 | else |
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61 | switch double(fsm_state) |
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62 | |
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63 | case ST_IDLE |
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64 | backoff_start = 0; |
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65 | phy_tx_start = 0; |
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66 | tx_done = 0; |
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67 | |
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68 | tx_result = TX_RESULT_NONE; |
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69 | |
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70 | if(new_tx) |
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71 | if(pre_wait_postRxTimer1 || pre_wait_postTxTimer1) |
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72 | %Tx scheduled for future, some fixed time after previous Tx/Rx |
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73 | fsm_state = ST_PRE_TX_WAIT; |
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74 | elseif(~backoff_done) |
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75 | %If backoff is already running, use it as our deferral |
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76 | fsm_state = ST_DEFER; |
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77 | elseif(idle_for_difs) |
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78 | %If no pre-Tx BO is required, any old backoff has expired and medium has been idle, |
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79 | % transmit immediately |
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80 | fsm_state = ST_DO_TX; |
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81 | else |
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82 | %If medium hasn't been idle, backoff |
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83 | fsm_state = ST_START_BO; |
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84 | end |
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85 | else |
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86 | fsm_state = ST_IDLE; |
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87 | end |
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88 | |
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89 | case ST_PRE_TX_WAIT |
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90 | backoff_start = 0; |
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91 | phy_tx_start = 0; |
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92 | tx_done = 0; |
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93 | |
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94 | tx_result = TX_RESULT_NONE; |
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95 | |
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96 | %Stay in PRE_TX_WAIT until the selected timer expires |
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97 | % MAC must take care if using both timers/conditions - only |
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98 | % the first will trigger a Tx, the other will expire without effect |
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99 | if( (pre_wait_postRxTimer1 && postRxTimer1_done) || (pre_wait_postTxTimer1 && postTxTimer1_done) ) |
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100 | fsm_state = ST_DO_TX; |
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101 | else |
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102 | fsm_state = ST_PRE_TX_WAIT; |
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103 | end |
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104 | |
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105 | case ST_START_BO |
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106 | %Start the backoff counter, then transition to DEFER |
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107 | backoff_start = 1; |
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108 | phy_tx_start = 0; |
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109 | tx_done = 0; |
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110 | |
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111 | tx_result = TX_RESULT_NONE; |
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112 | fsm_state = ST_DEFER; |
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113 | |
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114 | case ST_DEFER |
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115 | backoff_start = 0; |
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116 | phy_tx_start = 0; |
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117 | tx_done = 0; |
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118 | |
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119 | tx_result = TX_RESULT_NONE; |
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120 | |
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121 | %Stay here until backoff completes |
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122 | if(backoff_done) |
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123 | fsm_state = ST_DO_TX; |
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124 | else |
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125 | fsm_state = ST_DEFER; |
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126 | end |
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127 | |
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128 | case ST_DO_TX |
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129 | backoff_start = 0; |
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130 | phy_tx_start = 1; |
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131 | tx_done = 0; |
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132 | |
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133 | tx_result = TX_RESULT_NONE; |
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134 | |
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135 | % Stay here until PHY Tx finishes |
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136 | if(phy_tx_done) |
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137 | fsm_state = ST_POST_TX; |
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138 | else |
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139 | fsm_state = ST_DO_TX; |
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140 | end |
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141 | |
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142 | case ST_POST_TX |
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143 | backoff_start = 0; |
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144 | phy_tx_start = 0; |
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145 | tx_done = 0; |
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146 | |
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147 | tx_result = TX_RESULT_NONE; |
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148 | |
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149 | %If post-Tx timer is selected, transition to wait state |
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150 | if(post_wait_postTxTimer2) |
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151 | fsm_state = ST_POST_TX_WAIT; |
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152 | else |
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153 | fsm_state = ST_DONE; |
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154 | end |
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155 | |
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156 | case ST_POST_TX_WAIT |
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157 | backoff_start = 0; |
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158 | phy_tx_start = 0; |
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159 | tx_done = 0; |
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160 | |
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161 | % Stay in POST_TX_WAIT until PHY Rx starts or the post-Tx |
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162 | % timer expires. RX_START gets priority to handle unlikely |
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163 | % case of RX_START and timer_done asserting in the same cycle |
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164 | if(phy_rx_start) |
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165 | fsm_state = ST_DONE; |
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166 | tx_result = TX_RESULT_RX_STARTED; |
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167 | elseif(postTxTimer2_done) |
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168 | fsm_state = ST_DONE; |
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169 | tx_result = TX_RESULT_POSTTX_TIMER_EXPIRED; |
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170 | else |
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171 | fsm_state = ST_POST_TX_WAIT; |
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172 | tx_result = TX_RESULT_NONE; |
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173 | end |
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174 | |
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175 | case ST_DONE |
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176 | backoff_start = 0; |
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177 | phy_tx_start = 0; |
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178 | tx_done = 1; |
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179 | |
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180 | %Previous state set tx_result - leave it alone so downstream |
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181 | % logic can latch it when tx_done goes high |
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182 | |
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183 | fsm_state = ST_IDLE; |
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184 | |
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185 | otherwise |
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186 | %This case should be impossible; mostly here to appease MATLAB |
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187 | backoff_start = 0; |
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188 | phy_tx_start = 0; |
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189 | tx_done = 0; |
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190 | tx_result = TX_RESULT_NONE; |
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191 | fsm_state = ST_IDLE; |
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192 | |
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193 | end %end switch |
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194 | end %end else |
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195 | |
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196 | end %end function |
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197 | |
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