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TPIC8101: integrator output
I'm still working on a project utilising TPIC8101 but have come across something that I cannot interpret without trial-and-error.
"D9 to D8 of digital integrator output followed by six zeros"
1) How is D9:D8 laid out? Left-to-right? right-to-left? right-justified? left-justified?
And another question or two:
2) what is the bandwidth of the bandpass filter?
3) if microcontroller clock frequency is 16 MHz, set OSCin frequency to 16 MHz?
And to answer #1 myself:
"Byte 2" is formatted as: [ D9 D8 0 0 0 0 0 0 ]
And of course, "Byte 1" is formatted as: [ D7 D6 D5 D4 D3 D2 D1 D0 ]
I did end up finding and resolving the problem. I'm logging the data via serial to the PC via an custom graphing application I wrote. C++ uses serial 8-bit communications by default... where as C# uses 7-bit... which would explain the strange clipping I was seeing as I was graphing the knock signal/noise as an 8-bit value.
Sorry we dropped the ball on this one. Here is my feedback, this device is new to me and I had to dig up the information.
You are correct.
Byte 2: [ D9 D8 0 0 0 0 0 0 ]
Byte 1: [ D7 D6 D5 D4 D3 D2 D1 D0 ]
The Q-Factor for this filter is 2.30. Therefore from the center frequency that you set, and the Q-factor I just gave you, you can calculate the bandwidth of the filter.
I used the following website for the above information: http://www.sengpielaudio.com/calculator-cutoffFrequencies.htm
You are not calculating anything for this. You are just sending a clock signal into the device between 4MHz and 24MHz and then setting the prescalar with the value you are sending in. Page 13 of the datasheet. You basically are telling the device what the input frequency you are sending in and it will set the internal divider accordingly.
Hope this helps,
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