got the sonar sensor working again
diff --git a/bbb_cape/src/bbb/sensor_reader.cc b/bbb_cape/src/bbb/sensor_reader.cc
index 86d4d8b..c6d6521 100644
--- a/bbb_cape/src/bbb/sensor_reader.cc
+++ b/bbb_cape/src/bbb/sensor_reader.cc
@@ -73,6 +73,9 @@
         continue;
       }
       if (data->timestamp < last_cape_timestamp_) {
+        // TODO(brians): A common failure mode of the cape is to send the same 2
+        // packets (from the ring buffer) out repeatedly. Detect that and reset
+        // it.
         LOG(WARNING, "cape timestamp decreased: %" PRIu64 " to %" PRIu64 "\n",
             last_cape_timestamp_, data->timestamp);
         ResetHappened();
diff --git a/bbb_cape/src/cape/robot_comp.c b/bbb_cape/src/cape/robot_comp.c
index c33dc36..d7d8e8e 100644
--- a/bbb_cape/src/cape/robot_comp.c
+++ b/bbb_cape/src/cape/robot_comp.c
@@ -90,14 +90,14 @@
 SHOOTER(7, 5, 4, 8, 0)
 
 // TIM11.1 on PB9, aka digital input 6.
-timer_declare(TIM11, TIM1_TR_GCOM_TIM11_IRQHandler, 1, 1, ultrasonic)
+timer_declare(TIM11, TIM1_TRG_COM_TIM11_IRQHandler, 1, 1, ultrasonic)
 
 void robot_init(void) {
   gpio_setup_alt(GPIOB, 9, 3);
   RCC->APB2ENR |= RCC_APB2ENR_TIM11EN;
   TIM11->CCMR1 = TIM_CCMR1_CC1S_0 /* input pin 1 -> timer input 1 */;
   TIM11->PSC = 1200 - 1;  // 100KHz timer
-  //timer_setup(TIM11, TIM1_TRG_COM_TIM11_IRQn, 1);
+  timer_setup(TIM11, TIM1_TRG_COM_TIM11_IRQn, 1);
 }
 
 void robot_fill_packet(struct DataStruct *packet) {