PGA460-Q1: 20 meters distance measuring

Hi Gabriel,

The problem with your solution is that step 3's listen only command clears step 1's burst-and-listen 0-10m results from the ultrasonic measurement result registers. You need to swap the order of steps 3 and 4. However, you will still have a blind zone around 9~11m since you are reading back data and sending the listen only command during the same burst sequence. If you use USART/SPI interface with an 8MHz clock, you can minimize this blind zone to tens or hundreds of microseconds.

You may need to separate your 0-20m measurement into two independent measurements: 0-10m and 10-20m. Here is the most robust command sequence solution for 0-20m measurements, though it is more time consuming: 

1. Send Preset 1 Burst and Listen with maximum record length
2. Wait 60 milliseconds
3. Send Ultrasonic Measurement Result command to get 0-10m result.
4. Wait 60 milliseconds to allow residual ultrasonic echo activity to fully attenuate.
5. Send Preset 1 Burst and Listen with maximum record length
6. Wait 60 milliseconds
7. Send Preset 1 Listen Only with maximum record length
8. Wait 60 milliseconds
9. Send Ultrasonic Measurement Result command to get 10-20m result.