SLASEC8B February 2017 – January 2019 PGA460-Q1
The PGA460-Q1 device offers a data-dump function where the data at the output of the digital data path can be extracted in a raw digital format. This function is usually required for the ultrasonic system to be properly tuned and to make correct time-varying gain and threshold adjustments. Additional uses can include system evaluation and testing.
The echo data-dump function can be enabled for any of the four BURST/LISTEN or LISTEN ONLY commands and is enabled by the DATADUMP_EN bit in the EE_CNTRL register. When enabled, and upon receiving a BURST/LISTEN or a LISTEN ONLY command, the PGA460-Q1 device holds the IO pin low for the entire record interval thus signaling the master MCU that data-dump cycle is in progress. When the data-dump cycle is complete the data can be extracted by the data dump read command. For more information on the PGA460-Q1 device commands, see Table 2.
The data-dump memory is composed of a 128-byte data memory array. Echo data is down sampled to allow capturing of the complete recording interval. The down sampling amount depends on the record time-length parameter for the preset of interest set by the P1_REC and P2_REC bits in the REC_LENGTH EEPROM register. During the process of down-sampling, a peak hold function is performed and therefore only the highest level values after down-sampling are stored in the data-dump memory. When the DATADUMP_EN bit is 1, object detection and measurement is disabled.
The following is a brief example to present the data dump implementation:
Therefore the first data-dump value is the highest value of the 0–63 sample range while the last data-dump value is the highest value 8127–8191 sample range.