PGA460-Q1: Issue with 200khz ultrasonic transducer ....

In the PGA460 EVM GUI, I have incorporated a BPF coefficient calculator, which refers to the frequency and BPF bandwidth values entered on the GUI's General page. The PGA460 FAQ (www.ti.com/.../slaa733) explains the process of generating and setting the new coefficient values:

5.10 How do I successfully use a high-frequency transducer (180-480kHz) with the GUI?
To use a high-frequency transducer, follow these steps:
• On the General page in the Transmit block, check the Burst Frequency Range Shift box, select the
high-frequency value of the transducer, and select the band-pass filter bandwidth for the DSP.
• On the Utilities tab of the right panel in the BPF Coefficient Calculator block, check the Shift Range,
and select the same high frequency value of the transducer. The band-pass filter coefficient values A2,
A3, and B1 will automatically update based on the transducer frequency and band-pass filter
bandwidth.
• To update the coefficient values in the device register click the "Write Coefficients" button.
(Alternatively, on the Memory Map page, copy the calculated coefficient values into the register addresses 0x41 to
0x46, and write these values to update the DSP.)

The DSP is not automatically updated when the high-frequency mode is enabled, which is why the
coefficient registers must be updated manually. After the coefficients are manually updated, any change to
the frequency or band-pass filter bandwidth registers will overwrite the coefficients. Therefore, the
coefficients must be rewritten any time a change is applied to these two registers. The coefficients are
stored in volatile memory, thus the coefficients cannot be burned to the device, and must be written to at
initialization, along with the threshold, and the final solution.

Hello,
Thanks for the reply.My issue is if i am not using GUI then i have to send commands or write to register through UART .That PGA460 FAQ explained the steps but A2=E19F ,A3=F9A5 ,B1=032D ...Why E19F ,F9A5 ,032D only....how to calculate this values ...why this values only?....not getting accurate result using this value BPF coeffients for 200khz using pga460...please help me i really stuck with this.

Thank you.

vrushali,
You'll need to send a UART command-10 register write to update each of the coefficient registers manually. If you are not using the GUI, your master must transmit six independent commands:
• 0A 41 E1 D2 (register write a value of 0xE1 to register address 0x41 BPF_A2_MSB)
• 0A 42 9F 14 (register write a value of 0x9F to register address 0x42 BPF_A2_LSB)
• and so on for the remaining address of 0x43-0x46...

The coefficient values are dependent on the frequency and band-pass filter bandwidth, which is why {E19F ,F9A5 ,032D} is specific to a transducer frequency of 200.4kHz and a 4kHz BPF bandwidth. You can only use the PGA460-Q1 EVM GUI's Utilities --> BPF Coefficient Calculator to generate the coefficient values.

What driver mode are you using? If you are using a transformer, you must use a different transformer since the EVM provided transformer does not efficiently support the high-frequency transducers. I recommend that you use the TDK-EPCOS B78416A2386A003 for high-frequency transformers. You may need to contact TDK-EPCOS for samples.