Changes between Version 7 and Version 8 of 802.11/app_notes/FDD-NoMAC

Timestamp:

Feb 15, 2017, 9:55:50 AM (7 years ago)

Author:

murphpo

Comment:

--

802.11/app_notes/FDD-NoMAC

@@ -22 +22 @@
   * Tune the RF A and B interfaces to different channels
   * Disable logic paths that block simultaneous Tx/Rx PHY events
+  * Configure the Rx RF interface to stay active during Tx
  1. Update the NoMAC application to handle simultaneous Tx/Rx
 
@@ -51 +52 @@
 The lower MAC framework manages control of the MAC and PHY cores and the circuits in the RF interfaces. In the reference code the framework enables protection signals between the Tx PHY, Rx PHY and MAC cores that automatically reset the Rx PHY whenever the Tx PHY is active. These signals guarantee the node never receives its own transmissions, either through leakage from the Tx to Rx analog circuits on one interface or between RF interfaces when both are enabled. The lower framework also tunes both RF interfaces to the same center frequency whenever the MAC application requests a different channel.
 
-''' Tx/Rx Interlock ''': the PHY-level mutual-exclusion between Tx and Rx is enabled in two configuration registers, one in the Rx PHY, the other in the MAC core. To disable the interlock:
+'''Tx/Rx PHY Interlock'''[[BR]]
+The PHY-level mutual-exclusion between Tx and Rx is enabled in two configuration registers, one in the Rx PHY, the other in the MAC core. To disable the interlock:
 
 In {{{wlan_phy_util.c}}} modify the {{{wlan_phy_init()}}} function:
@@ -69 +71 @@
 }}}
 
-''' Different Channels on RF A/B ''': the reference code tunes all RF interfaces to the same center frequency any time the MAC application requests a new channel. The RF interfaces are tuned in the {{{wlan_mac_low_set_radio_channel(u32 channel)}}} function in {{{wlan_mac_low.c}}}. The {{{channel}}} argument is an 802.11 channel index. This function also enables/disables the Rx PHY DSSS receiver when tuned to a 5 GHz channel, as DSSS transmissions only occur in 2.4 GHz channels.
+'''Keep Rx RF Interface Enabled'''[[BR]]
+The reference code disables the Rx circuits on every RF interface when any interface is currently transmitting. For FDD the Rx interface must be configued to say in Rx mode independent of the Tx state of another interface. This is achieved by modifying the framework's {{{wlan_rx_config_ant_mode()}}} function in {{{wlan_phy_util.c}}}. Changes are required to 5 lines (add 3 lines, comment-out 2 lines), identified by the inline comments below:
+
+{{{#!c
+
+...
+    // Disable PHY control of all RF interfaces - selected interfaces to re-enabled below
+    radio_controller_setCtrlSource(RC_BASEADDR, RC_ALL_RF, RC_REG0_RXEN_CTRLSRC, RC_CTRLSRC_REG);
+
+    // Disable all RF interfaces that are already software-controlled
+    radio_controller_TxRxDisable(RC_BASEADDR, RC_ALL_RF); // FDD-NoMAC
+
+    switch (ant_mode) {
+        case RX_ANTMODE_SISO_ANTA:
+            REG_SET_BITS(WLAN_RX_REG_CFG, WLAN_RX_REG_CFG_PKT_DET_EN_ANT_A);
+            wlan_phy_select_rx_antenna(RX_ANTMODE_SISO_ANTA);
+            //radio_controller_setCtrlSource(RC_BASEADDR, RC_RFA, RC_REG0_RXEN_CTRLSRC, RC_CTRLSRC_HW); // ref code
+            radio_controller_RxEnable(RC_BASEADDR, RC_RFA); // FDD-NoMAC
+            wlan_agc_config(RX_ANTMODE_SISO_ANTA);
+        break;
+
+        case RX_ANTMODE_SISO_ANTB:
+            REG_SET_BITS(WLAN_RX_REG_CFG, WLAN_RX_REG_CFG_PKT_DET_EN_ANT_B);
+            wlan_phy_select_rx_antenna(RX_ANTMODE_SISO_ANTB);
+            //radio_controller_setCtrlSource(RC_BASEADDR, RC_RFB, RC_REG0_RXEN_CTRLSRC, RC_CTRLSRC_HW); // ref code
+            radio_controller_RxEnable(RC_BASEADDR, RC_RFB); // FDD-NoMAC
+            wlan_agc_config(RX_ANTMODE_SISO_ANTB);
+        break;
+   ...
+}}}
+
+
+'''Different Channels on RF A/B'''[[BR]]
+The reference code tunes all RF interfaces to the same center frequency any time the MAC application requests a new channel. The RF interfaces are tuned in the {{{wlan_mac_low_set_radio_channel(u32 channel)}}} function in {{{wlan_mac_low.c}}}. The {{{channel}}} argument is an 802.11 channel index. This function also enables/disables the Rx PHY DSSS receiver when tuned to a 5 GHz channel, as DSSS transmissions only occur in 2.4 GHz channels.
 
 A fully-general FDD implementation would modify this function to support a channel argument per RF interface. However this app note adopts the simpler scheme of: