adding support for beam selection in usrp_lib

executables/nr-ru.c

@@ -755,6 +755,10 @@ void tx_rf(RU_t *ru,int frame,int slot, uint64_t timestamp) {
       flags = 3; // end of burst
     }
 
+    // the beam index is written in bits 8-10 of the flags
+    // the following choice cycles through the beams every slot, starting with beam 3
+    flags |= ((3+slot)&7)<<8;
+   
     VCD_SIGNAL_DUMPER_DUMP_VARIABLE_BY_NAME( VCD_SIGNAL_DUMPER_VARIABLES_TRX_WRITE_FLAGS, flags ); 
     VCD_SIGNAL_DUMPER_DUMP_VARIABLE_BY_NAME( VCD_SIGNAL_DUMPER_VARIABLES_FRAME_NUMBER_TX0_RU, frame );
     VCD_SIGNAL_DUMPER_DUMP_VARIABLE_BY_NAME( VCD_SIGNAL_DUMPER_VARIABLES_TTI_NUMBER_TX0_RU, slot );

targets/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp

@@ -276,14 +276,17 @@ static int trx_usrp_start(openair0_device *device) {
 
   // setup GPIO for TDD, GPIO(4) = ATR_RX
   //set data direction register (DDR) to output
-  s->usrp->set_gpio_attr("FP0", "DDR", 0x7f, 0x7f);
-  //set control register to ATR
-  s->usrp->set_gpio_attr("FP0", "CTRL", 0x7f,0x7f);
+  s->usrp->set_gpio_attr("FP0", "DDR", 0xfff, 0xfff);
+  //set lower 7 bits to be controlled automatically by ATR (the rest 5 bits are controlled manually) 
+  s->usrp->set_gpio_attr("FP0", "CTRL", 0x7f,0xfff);
   //set pins 4 (RX_TX_Switch) and 6 (Shutdown PA) to 1 when the radio is only receiving (ATR_RX)
   s->usrp->set_gpio_attr("FP0", "ATR_RX", (1<<4)|(1<<6), 0x7f);
   // set pin 5 (Shutdown LNA) to 1 when the radio is transmitting and receiveing (ATR_XX)
   // (we use full duplex here, because our RX is on all the time - this might need to change later)
   s->usrp->set_gpio_attr("FP0", "ATR_XX", (1<<5), 0x7f);
+  // set the output pins to 0
+  s->usrp->set_gpio_attr("FP0", "OUT", 3<<7, 0xf80);
+
   // init recv and send streaming
   uhd::stream_cmd_t cmd(uhd::stream_cmd_t::STREAM_MODE_START_CONTINUOUS);
   LOG_I(HW,"Time in secs now: %llu \n", s->usrp->get_time_now().to_ticks(s->sample_rate));
@@ -404,10 +407,19 @@ static int trx_usrp_write_recplay(openair0_device *device, openair0_timestamp ti
       @param antenna_id index of the antenna if the device has multiple antennas
       @param flags flags must be set to TRUE if timestamp parameter needs to be applied
 */
-static int trx_usrp_write(openair0_device *device, openair0_timestamp timestamp, void **buff, int nsamps, int cc, int flags) {
+static int trx_usrp_write(openair0_device *device,
+			  openair0_timestamp timestamp,
+			  void **buff,
+			  int nsamps,
+			  int cc,
+			  int flags) {
   int ret=0;
   usrp_state_t *s = (usrp_state_t *)device->priv;
   int nsamps2;  // aligned to upper 32 or 16 byte boundary
+
+  int flags_lsb = flags&0xff;
+  int flags_msb = (flags>>8)&0xff;
+    
 #if defined(__x86_64) || defined(__i386__)
   #ifdef __AVX2__
       nsamps2 = (nsamps+7)>>3;
@@ -441,27 +453,28 @@ static int trx_usrp_write(openair0_device *device, openair0_timestamp timestamp,
 
     boolean_t first_packet_state=false,last_packet_state=false;
 
-    if (flags == 2) { // start of burst
+    if (flags_lsb == 2) { // start of burst
       //      s->tx_md.start_of_burst = true;
       //      s->tx_md.end_of_burst = false;
       first_packet_state = true;
       last_packet_state  = false;
-    } else if (flags == 3) { // end of burst
+    } else if (flags_lsb == 3) { // end of burst
       //s->tx_md.start_of_burst = false;
       //s->tx_md.end_of_burst = true;
       first_packet_state = false;
       last_packet_state  = true;
-    } else if (flags == 4) { // start and end
+    } else if (flags_lsb == 4) { // start and end
     //  s->tx_md.start_of_burst = true;
     //  s->tx_md.end_of_burst = true;
       first_packet_state = true;
       last_packet_state  = true;
-    } else if (flags==1) { // middle of burst
+    } else if (flags_lsb==1) { // middle of burst
     //  s->tx_md.start_of_burst = false;
     //  s->tx_md.end_of_burst = false;
       first_packet_state = false;
       last_packet_state  = false;
-    } else if (flags==10) { // fail safe mode
+    }
+    else if (flags_lsb==10) { // fail safe mode
      // s->tx_md.has_time_spec = false;
      // s->tx_md.start_of_burst = false;
      // s->tx_md.end_of_burst = true;
@@ -469,12 +482,19 @@ static int trx_usrp_write(openair0_device *device, openair0_timestamp timestamp,
      last_packet_state  = true;
     }
 
+    // push GPIO bits 7-9 from flags_msb
+    int gpio789=(flags_msb&7)<<7;
+    
     s->tx_md.has_time_spec  = true;
     s->tx_md.start_of_burst = (s->tx_count==0) ? true : first_packet_state;
     s->tx_md.end_of_burst   = last_packet_state;
     s->tx_md.time_spec      = uhd::time_spec_t::from_ticks(timestamp, s->sample_rate);
     s->tx_count++;
 
+    s->usrp->set_command_time(s->tx_md.time_spec);
+    s->usrp->set_gpio_attr("FP0", "OUT", gpio789, 0xfff);
+    s->usrp->clear_command_time();
+    
     if (cc>1) {
       std::vector<void *> buff_ptrs;