Dear Sirs,
I have procured two development kits TUSS4470 based (MIKROE-5087 - 5 clicks Ultrasounds). Following some hints from the Community and the TI datasheet of the IC I could get the first board operating rather soon. I even could observe initially the OUT3 square wave generation at 40 kHz frequency, expected for ultrasonic part UTR-1440K-TT-R annexed in the kit.
However, I have soon after realized to have achieved the OUT3 performing just by case. Indeed once I've better stabilized the code to properly support odd parity in the commands and improved the initialization of the IC, I could not see any more any output activity on the OUT3 line. I even replaced the kit with a new one to be sure that the problem was not caused by a possible pin out damaging of the OUT3 line.
I really need this OUT3 output operating, because my intent is to perform some Doppler measurements and without it I can not do anything with this TUSS4470. I tried all the possible configurations of the ZC_CONFIG Register, but OUT3 persisted to remain permanently low. Filters setting and signals are good enough, I believe, being VOUT of the order of more than 2V and Flt out exceed 1 Volt. But as you know they are enveloped signals conditioned by low pass filtering and they can not be used for my scope.
I may understand, the success in having the OUT3 line working may depend on the actual echo. You mentioned that the related comparator performs the switching according to input compared to the level of VCM or in alternative of the INN line, but VCM is not mentioned at all in the datasheet, I may argue that is half of the DC powering, conversely INN may be managed outside the IC.
Could you please provide me a simple list of commands ideal from your point of you to get this OUT3 really generated, when the TUSS4470 is operated with a part like the UTR-1440K-TT-R?
Thank in advance, for any support that about, I wish not to change IC unless I am forced because I can not fix of the above issue.
Sincerely, Andrea
